Tag: TCA: Tricyclic Antidepressants

What is Butriptyline?

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Introduction

Butriptyline, sold under the brand name Evadyne among others, is a tricyclic antidepressant (TCA) that has been used in the United Kingdom and several other European countries for the treatment of depression but appears to no longer be marketed. Along with trimipramine, iprindole, and amoxapine, it has been described as an “atypical” or “second-generation” TCA due to its relatively late introduction and atypical pharmacology. It was very little-used compared to other TCAs, with the number of prescriptions dispensed only in the thousands.

Brief History

Butriptyline was developed by Wyeth, an American pharmaceutical company, and introduced in the United Kingdom in either 1974 or 1975.

Medical Uses

Butriptyline was used in the treatment of depression. It was usually used at dosages of 150-300 mg/day.

Side Effects

Butriptyline is closely related to amitriptyline, and produces similar effects as other TCAs, but its side effects like sedation are said to be reduced in severity and it has a lower risk of interactions with other medications.

Butriptyline has potent antihistamine effects, resulting in sedation and somnolence. It also has potent anticholinergic effects, resulting in side effects like dry mouth, constipation, urinary retention, blurred vision, and cognitive/memory impairment. The drug has relatively weak effects as an alpha-1 blocker and has no effects as a norepinephrine reuptake inhibitor, so is associated with little to no antiadrenergic and adrenergic side effects.

Overdose

Refer to Tricyclic Antidepressant Overdose.

Pharmacology

Pharmacodynamics

In vitro, butriptyline is a strong antihistamine and anticholinergic, moderate 5-HT2 and α1-adrenergic receptor antagonist, and very weak or negligible monoamine reuptake inhibitor. These actions appear to confer a profile similar to that of iprindole and trimipramine with serotonin-blocking effects as the apparent predominant mediator of mood-lifting efficacy.

However, in small clinical trials, using similar doses, butriptyline was found to be similarly effective to amitriptyline and imipramine as an antidepressant, despite the fact that both of these TCAs are far stronger as both 5-HT2 antagonists and serotonin–norepinephrine reuptake inhibitors. As a result, it may be that butriptyline has a different mechanism of action, or perhaps functions as a prodrug in the body to a metabolite with different pharmacodynamics.

Pharmacokinetics

Therapeutic concentrations of butriptyline are in the range of 60-280 ng/mL (204-954 nmol/L). Its plasma protein binding is greater than 90%.

Chemistry

Butriptyline is a tricyclic compound, specifically a dibenzocycloheptadiene, and possesses three rings fused together with a side chain attached in its chemical structure. Other dibenzocycloheptadiene TCAs include amitriptyline, nortriptyline, and protriptyline. Butriptyline is an analogue of amitriptyline with an isobutyl side chain instead of a propylidene side chain. It is a tertiary amine TCA, with its side chain-demethylated metabolite norbutriptyline being a secondary amine. Other tertiary amine TCAs include amitriptyline, imipramine, clomipramine, dosulepin (dothiepin), doxepin, and trimipramine. The chemical name of butriptyline is 3-(10,11-dihydro-5H-dibenzo[a,d]cycloheptene-5-yl)-N,N,2-trimethylpropan-1-amine and its free base form has a chemical formula of C21H27N with a molecular weight of 293.446 g/mol. The drug has been used commercially both as the free base and as the hydrochloride salt. The CAS Registry Number of the free base is 15686-37-0 and of the hydrochloride is 5585-73-9.

Society and Culture

Generic Names

Butriptyline is the English and French generic name of the drug and its International Non-Propriety Name (INN), British Approved Name (BAN), and Denomination Commune Francaise (DCF), while butriptyline hydrochloride is its BANM and (United States Adopted Name (USAN). Its generic name in Latin is butriptylinum, in German is butriptylin, and in Spanish is butriptylina.

Brand Names

Butriptyline has been marketed under the brand names Evadene, Evadyne, Evasidol, and Centrolese.

Availability

Butriptyline has been marketed in Europe, including in the United Kingdom, Belgium, Luxembourg, Austria, and Italy.

This page is based on the copyrighted Wikipedia article < https://en.wikipedia.org/wiki/Butriptyline >; it is used under the Creative Commons Attribution-ShareAlike 3.0 Unported License (CC-BY-SA). You may redistribute it, verbatim or modified, providing that you comply with the terms of the CC-BY-SA.

What is Amoxapine?

Published on by Andrew Marshall1 Comment

Introduction

Amoxapine, sold under the brand name Asendin among others, is a tricyclic antidepressant (TCAs). It is the N-demethylated metabolite of loxapine. Amoxapine first received marketing approval in the United States in 1992 (approximately 30 to 40 years after most of the other TCAs were introduced in the United States).

Medical Uses

Moxapine is used in the treatment of major depressive disorder (MDD). Compared to other antidepressants it is believed to have a faster onset of action, with therapeutic effects seen within four to seven days. In excess of 80% of patients that do respond to amoxapine are reported to respond within two weeks of the beginning of treatment. It also has properties similar to those of the atypical antipsychotics, and may behave as one and may be used in the treatment of schizophrenia off-label. Despite its apparent lack of extrapyramidal side effects in patients with schizophrenia it has been found to exacerbate motor symptoms in patients with Parkinson’s disease and psychosis.

Contraindications

As with all US Food and Drug Administration (FDA)-approved antidepressants it carries a black-box warning about the potential of an increase in suicidal thoughts or behaviour in children, adolescents and young adults under the age of 25. Its use is also advised against in individuals with known hypersensitivities to either amoxapine or other ingredients in its oral formulations. Its use is also recommended against in the following disease states:

  • Severe cardiovascular disorders (potential of cardiotoxic adverse effects such as QT interval prolongation).
  • Uncorrected narrow angle glaucoma.
  • Acute recovery post-myocardial infarction.

Its use is also advised against in individuals concurrently on monoamine oxidase inhibitors or if they have been on one in the past 14 days and in individuals on drugs that are known to prolong the QT interval (e.g. ondansetron, citalopram, pimozide, sertindole, ziprasidone, haloperidol, chlorpromazine, thioridazine, etc.).

Lactation

Its use in breastfeeding mothers not recommended as it is excreted in breast milk and the concentration found in breast milk is approximately a quarter that of the maternal serum level.

Side Effects

Very Common (>10% Incidence) Adverse Effects Include:

  • Constipation.
  • Dry mouth.
  • Sedation.

Common (1–10% Incidence) Adverse Effects Include:

  • Anxiety.
  • Ataxia.
  • Blurred vision.
  • Confusion.
  • Dizziness.
  • Headache.
  • Fatigue.
  • Nausea.
  • Nervousness/restlessness.
  • Excessive appetite.
  • Rash.
  • Increased perspiration (sweating).
  • Tremor.
  • Palpitations.
  • Nightmares.
  • Excitement.
  • Weakness.
  • ECG changes.
  • Oedema.
    • An abnormal accumulation of fluids in the tissues of the body leading to swelling.
  • Prolactin levels increased.
    • Prolactin is a hormone that regulates the generation of breast milk.
    • Prolactin elevation is not as significant as with risperidone or haloperidol.

Uncommon/Rare (<1% Incidence) Adverse Effects Include:

  • Diarrhoea.
  • Flatulence.
  • Hypertension (high blood pressure).
  • Hypotension (low blood pressure).
  • Syncope (fainting).
  • Tachycardia (high heart rate).
  • Menstrual irregularity.
  • Disturbance of accommodation.
  • Mydriasis (pupil dilation).
  • Orthostatic hypotension (a drop in blood pressure that occurs upon standing up).
  • Seizure.
  • Urinary retention (being unable to pass urine).
  • Urticaria (hives).
  • Vomiting.
  • Nasal congestion.
  • Photosensitisation
  • Hypomania (a dangerously elated/irritable mood).
  • Tingling.
  • Paresthaesias of the extremities.
  • Tinnitus.
  • Disorientation.
  • Numbness.
  • Incoordination.
  • Disturbed concentration.
  • Epigastric distress.
  • Peculiar taste in the mouth.
  • Increased or decreased libido.
  • Impotence (difficulty achieving an erection).
  • Painful ejaculation.
  • Lacrimation (crying without an emotional cause).
  • Weight gain.
  • Altered liver function.
  • Breast enlargement.
  • Drug fever.
  • Pruritus (itchiness).
  • Vasculitis a disorder where blood vessels are destroyed by inflammation.
    • Can be life-threatening if it affects the right blood vessels.
  • Galactorrhoea:
    • Lactation that is not associated with pregnancy or breast feeding.
  • Delayed micturition:
    • That is, delays in urination from when a conscious effort to urinate is made.
  • Hyperthermia:
    • Elevation of body temperature; its seriousness depends on the extent of the hyperthermia.
  • Syndrome of inappropriate secretion of antidiuretic hormone (SIADH) this is basically when the body’s level of the hormone, antidiuretic hormone, which regulates the conservation of water and the restriction of blood vessels, is elevated.
    • This is potentially fatal as it can cause electrolyte abnormalities including hyponatraemia (low blood sodium), hypokalaemia (low blood potassium) and hypocalcaemia (low blood calcium) which can be life-threatening.
  • Agranulocytosis a drop in white blood cell counts.
    • The white blood cells are the cells of the immune system that fight off foreign invaders.
    • Hence agranulocytosis leaves an individual open to life-threatening infections.
  • Leukopaenia the same as agranulocytosis but less severe.
  • Neuroleptic malignant syndrome (a potentially fatal reaction to antidopaminergic agents, most often antipsychotics.
    • It is characterised by hyperthermia, diarrhoea, tachycardia, mental status changes [e.g. confusion], rigidity, extrapyramidal side effects)
  • Tardive dyskinesia a most often irreversible neurologic reaction to antidopaminergic treatment, characterised by involuntary movements of facial muscles, tongue, lips, and other muscles.
    • It develops most often only after prolonged (months, years or even decades) exposure to antidopaminergics.
  • Extrapyramidal side effects.
    • Motor symptoms such as tremor, parkinsonism, involuntary movements, reduced ability to move one’s voluntary muscles, etc.

Unknown Incidence or Relationship to Drug Treatment Adverse Effects Include:

  • Paralytic ileus (paralysed bowel).
  • Atrial arrhythmias including atrial fibrillation.
  • Myocardial infarction (heart attack).
  • Stroke.
  • Heart block.
  • Hallucinations.
  • Purpura.
  • Petechiae.
  • Parotid swelling.
  • Changes in blood glucose levels.
  • Pancreatitis swelling of the pancreas.
  • Hepatitis swelling of the liver.
  • Urinary frequency.
  • Testicular swelling.
  • Anorexia (weight loss).
  • Alopecia (hair loss).
  • Thrombocytopenia:
    • A significant drop in platelet count that leaves one open to life-threatening bleeds.
  • Eosinophilia an elevated level of the eosinophils of the body.
    • Eosinophils are the type of immune cell that’s job is to fight off parasitic invaders.
  • Jaundice:
    • yellowing of the skin, eyes and mucous membranes due to an impaired ability of the body to clear the by product of haem breakdown, bilirubin, most often the result of liver damage as it is the liver’s responsibility to clear bilirubin.

It tends to produce less anticholinergic effects, sedation and weight gain than some of the earlier TCAs (e.g. amitriptyline, clomipramine, doxepin, imipramine, trimipramine). It may also be less cardiotoxic than its predecessors.

Overdose

Refer to Tricyclic Antidepressant Overdose.

It is considered particularly toxic in overdose, with a high rate of renal failure (which usually takes 2-5 days), rhabdomyolysis, coma, seizures and even status epilepticus. Some believe it to be less cardiotoxic than other TCAs in overdose, although reports of cardiotoxic overdoses have been made.

Pharmacology

Pharmacodynamics

Amoxapine possesses a wide array of pharmacological effects. It is a moderate and strong reuptake inhibitor of serotonin and norepinephrine, respectively, and binds to the 5-HT2A, 5-HT2B, 5-HT2C, 5-HT3, 5-HT6, 5-HT7, D2, α1-adrenergic, D3, D4, and H1 receptors with varying but significant affinity, where it acts as an antagonist (or inverse agonist depending on the receptor in question) at all sites. It has weak but negligible affinity for the dopamine transporter and the 5-HT1A, 5-HT1B, D1, α2-adrenergic, H4, mACh, and GABAA receptors, and no affinity for the β-adrenergic receptors or the allosteric benzodiazepine site on the GABAA receptor. Amoxapine is also a weak GlyT2 blocker, as well as a weak (Ki = 2.5 μM, EC50 = 0.98 μM) δ-opioid receptor partial agonist.

7-Hydroxyamoxapine, a major active metabolite of amoxapine, is a more potent dopamine receptor antagonist and contributes to its neuroleptic efficacy, whereas 8-hydroxyamoxapine is a norepinephrine reuptake inhibitor but a stronger serotonin reuptake inhibitor and helps to balance amoxapine’s ratio of serotonin to norepinephrine transporter blockade

Pharmacokinetics

Amoxapine is metabolised into two main active metabolites: 7-hydroxyamoxapine and 8-hydroxyamoxapine.

Society and Culture

Brand Names

Brand names for amoxapine include (where † denotes discontinued brands):

  • Adisen (KR).
  • Amolife (IN).
  • Amoxan (JP).
  • Asendin† (previously marketed in CA, NZ, US).
  • Asendis† (previously marketed in IE, UK).
  • Défanyl (FR).
  • Demolox (DK†, IN, ES†).
  • Oxamine (IN).
  • Oxcap.

This page is based on the copyrighted Wikipedia article < https://en.wikipedia.org/wiki/Amoxapine >; it is used under the Creative Commons Attribution-ShareAlike 3.0 Unported License (CC-BY-SA). You may redistribute it, verbatim or modified, providing that you comply with the terms of the CC-BY-SA.

What is Amitriptyline?

Published on by Andrew Marshall2 Comments

Introduction

Amitriptyline, sold under the brand name Elavil among others, is a tricyclic antidepressant (TCA) primarily used to treat cyclic vomiting syndrome (CVS), major depressive disorder (MDD) and a variety of pain syndromes from neuropathic pain to fibromyalgia to migraine and tension headaches. Due to the frequency and prominence of side effects, amitriptyline is generally considered a second-line therapy for these indications.

The most common side effects are dry mouth, drowsiness, dizziness, constipation, and weight gain. Of note is sexual dysfunction, observed primarily in males. Glaucoma, liver toxicity and abnormal heart rhythms are rare but serious side effects. Blood levels of amitriptyline vary significantly from one person to another, and amitriptyline interacts with many other medications potentially aggravating its side effects.

Amitriptyline was discovered in the late 1950s by scientists at Merck and approved by the US Food and Drug Administration (FDA) in 1961. It is on the World Health Organisation’s List of Essential Medicines. It is available as a generic medication. In 2019, it was the 94th most commonly prescribed medication in the United States, with more than 8 million prescriptions.

Brief History

Amitriptyline was first developed by the American pharmaceutical company Merck in the late 1950s. In 1958, Merck approached a number of clinical investigators proposing to conduct clinical trials of amitriptyline for schizophrenia. One of these researchers, Frank Ayd, instead, suggested using amitriptyline for depression. Ayd treated 130 patients and, in 1960, reported that amitriptyline had antidepressant properties similar to another, and the only known at the time, tricyclic antidepressant imipramine. Following this, the FDA approved amitriptyline for depression in 1961.

In Europe, due to a quirk of the patent law at the time allowing patents only on the chemical synthesis but not on the drug itself, Roche and Lundbeck were able to independently develop and market amitriptyline in the early 1960s.

According to research by the historian of psychopharmacology David Healy, amitriptyline became a much bigger selling drug than its precursor imipramine because of two factors. First, amitriptyline has much stronger anxiolytic effect. Second, Merck conducted a marketing campaign raising clinicians’ awareness of depression as a clinical entity.

Medical Uses

Amitriptyline is indicated for the treatment of major depressive disorder and neuropathic pain and for the prevention of migraine and chronic tension headache. It can be used for the treatment of nocturnal enuresis in children older than 6 after other treatments have failed.

Depression

Amitriptyline is effective for depression, but it is rarely used as a first-line antidepressant due to its higher toxicity in overdose and generally poorer tolerability. It can be tried for depression as a second-line therapy, after the failure of other treatments. For treatment-resistant adolescent depression or for cancer-related depression amitriptyline is no better than placebo. It is sometimes used for the treatment of depression in Parkinson’s disease, but supporting evidence for that is lacking.

Pain

Amitriptyline alleviates painful diabetic neuropathy. It is recommended by a variety of guidelines as a first or second line treatment. It is as effective for this indication as gabapentin or pregabalin but less well tolerated.

Low doses of amitriptyline moderately improve sleep disturbances and reduce pain and fatigue associated with fibromyalgia. It is recommended for fibromyalgia accompanied by depression by Association of the Scientific Medical Societies in Germany and as a second-line option for fibromyalgia, with exercise being the first line option, by European League Against Rheumatism. Combinations of amitriptyline and fluoxetine or melatonin may reduce fibromyalgia pain better than either medication alone.

There is some (low-quality) evidence that amitriptyline may reduce pain in cancer patients. It is recommended only as a second line therapy for non-chemotherapy-induced neuropathic or mixed neuropathic pain, if opioids did not provide the desired effect.

Moderate evidence exists in favour of amitriptyline use for atypical facial pain. Amitriptyline is ineffective for HIV-associated neuropathy.

Headache

Amitriptyline is probably effective for the prevention of periodic migraine in adults. Amitriptyline is similar in efficacy to venlafaxine and topiramate but carries a higher burden of adverse effects than topiramate. For many patients, even very small doses of amitriptyline are helpful, which may allow for minimization of side effects. Amitriptyline is not significantly different from placebo when used for the prevention of migraine in children.

Amitriptyline may reduce the frequency and duration of chronic tension headache, but it is associated with worse adverse effects than mirtazapine. Overall, amitriptyline is recommended for tension headache prophylaxis, along with lifestyle advice, which should include avoidance of analgesia and caffeine.

Other Indications

Amitriptyline is effective for the treatment of irritable bowel syndrome; however, because of its side effects, it should be reserved for select patients for whom other agents do not work. There is insufficient evidence to support its use for abdominal pain in children with functional gastrointestinal disorders.

Tricyclic antidepressants decrease the frequency, severity, and duration of cyclic vomiting syndrome episodes. Amitriptyline, as the most commonly used of them, is recommended as a first-line agent for its therapy.

Amitriptyline may improve pain and urgency intensity associated with bladder pain syndrome and can be used in the management of this syndrome. Amitriptyline can be used in the treatment of nocturnal enuresis in children. However, its effect is not sustained after the treatment ends. Alarm therapy gives better short- and long-term results.

In the US, amitriptyline is commonly used in children with ADHD as an adjunct to stimulant medications without any evidence or guideline supporting this practice. Many physicians in the UK (and the US also) commonly prescribe amitriptyline for insomnia; however, Cochrane reviewers were not able to find any randomised controlled studies that would support or refute this practice.

Contraindications and Precautions

The known contraindications of amitriptyline are:

  • History of myocardial infarction.
  • History of arrhythmias, particularly any degree of heart block.
  • Coronary artery disease.
  • Porphyria.
  • Severe liver disease (such as cirrhosis).
  • Being under six years of age.
  • Patients who are taking monoamine oxidase inhibitors (MAOIs) or have taken them within the last 14 days.

Amitriptyline should be used with caution in patients with epilepsy, impaired liver function, pheochromocytoma, urinary retention, prostate enlargement, hyperthyroidism, and pyloric stenosis.

In patients with the rare condition of shallow anterior chamber of eyeball and narrow anterior chamber angle, amitriptyline may provoke attacks of acute glaucoma due to dilation of the pupil. It may aggravate psychosis, if used for depression with schizophrenia, or precipitate the switch to mania in those with bipolar disorder.

CYP2D6 poor metabolisers should avoid amitriptyline due to increased side effects. If it is necessary to use it, half dose is recommended. Amitriptyline can be used during pregnancy and lactation, in the cases when SSRI do not work.

Side Effects

The most frequent side effects, occurring in 20% or more of users, are dry mouth, drowsiness, dizziness, constipation, and weight gain (on average 1.8 kg). Other common side effects (in 10% or more) are vision problems (amblyopia, blurred vision), tachycardia, increased appetite, tremor, fatigue/asthenia/feeling slowed down, and dyspepsia.

A literature review about abnormal movements and amitriptyline found that this drug is associated with various movement disorders, particularly dyskinesia, dystonia, and myoclonus. Stuttering and restless legs syndrome are some of the less common associations.

A less common side effect of amitriptyline is urination problems (8.7%).

Amitriptyline-associated sexual dysfunction (occurring at a frequency of 6.9%) seems to be mostly confined to males with depression and is expressed predominantly as erectile dysfunction and low libido disorder, with lesser frequency of ejaculatory and orgasmic problems. The rate of sexual dysfunction in males treated for indications other than depression and in females is not significantly different from placebo.

Liver tests abnormalities occur in 10-12% of patients on amitriptyline, but are usually mild, asymptomatic and transient, with consistently elevated alanine transaminase in 3% of all patients. The increases of the enzymes above the 3-fold threshold of liver toxicity are uncommon, and cases of clinically apparent liver toxicity are rare; nevertheless, amitriptyline is placed in the group of antidepressants with greater risks of hepatic toxicity.

Amitriptyline prolongs the QT interval. This prolongation is relatively small at therapeutic doses but becomes severe in overdose.

Overdose

Refer to Tricyclic Antidepressant Overdose.

The symptoms and the treatment of an overdose are largely the same as for the other TCAs, including the presentation of serotonin syndrome and adverse cardiac effects. The British National Formulary notes that amitriptyline can be particularly dangerous in overdose, thus it and other TCAs are no longer recommended as first-line therapy for depression. The treatment of overdose is mostly supportive as no specific antidote for amitriptyline overdose is available. Activated charcoal may reduce absorption if given within 1-2 hours of ingestion. If the affected person is unconscious or has an impaired gag reflex, a nasogastric tube may be used to deliver the activated charcoal into the stomach. ECG monitoring for cardiac conduction abnormalities is essential and if one is found close monitoring of cardiac function is advised. Body temperature should be regulated with measures such as heating blankets if necessary. Cardiac monitoring is advised for at least five days after the overdose. Benzodiazepines are recommended to control seizures. Dialysis is of no use due to the high degree of protein binding with amitriptyline.

Interactions

Since amitriptyline and its active metabolite nortriptyline are primarily metabolised by cytochromes CYP2D6 and CYP2C19, the inhibitors of these enzymes are expected to exhibit pharmacokinetic interactions with amitriptyline. According to the prescribing information, the interaction with CYP2D6 inhibitors may increase the plasma level of amitriptyline. However, the results in the other literature are inconsistent: the co-administration of amitriptyline with a potent CYP2D6 inhibitor paroxetine does increase the plasma levels of amitriptyline two-fold and of the main active metabolite nortriptyline 1.5-fold, but combination with less potent CYP2D6 inhibitors thioridazine or levomepromazine does not affect the levels of amitriptyline and increases nortriptyline by about 1.5-fold; a moderate CYP2D6 inhibitor fluoxetine does not seem to have a significant effect on the levels of amitriptyline or nortriptyline. A case of clinically significant interaction with potent CYP2D6 inhibitor terbinafine has been reported.

A potent inhibitor of CYP2C19 and other cytochromes fluvoxamine increases the level of amitriptyline two-fold while slightly decreasing the level of nortriptyline. Similar changes occur with a moderate inhibitor of CYP2C19 and other cytochromes cimetidine: amitriptyline level increases by about 70%, while nortriptyline decreases by 50%. CYP3A4 inhibitor ketoconazole elevates amitriptyline level by about a quarter. On the other hand, cytochrome P450 inducers such as carbamazepine and St. John’s Wort decrease the levels of both amitriptyline and nortriptyline.

Oral contraceptives may increase the blood level of amitriptyline by as high as 90%. Valproate moderately increases the levels of amitriptyline and nortriptyline through an unclear mechanism.

The prescribing information warns that the combination of amitriptyline with monoamine oxidase inhibitors may cause potentially lethal serotonin syndrome; however, this has been disputed. The prescribing information cautions that some patients may experience a large increase in amitriptyline concentration in the presence of topiramate. However, other literature states that there is little or no interaction: in a pharmacokinetic study topiramate only increased the level of amitriptyline by 20% and nortriptyline by 33%.

Amitriptiline counteracts the antihypertensive action of guanethidine. When given with amitriptyline, other anticholinergic agents may result in hyperpyrexia or paralytic ileus. Co-administration of amitriptyline and disulfiram is not recommended due to the potential for the development of toxic delirium. Amitriptyline causes an unusual type of interaction with the anticoagulant phenprocoumon during which great fluctuations of the prothrombin time have been observed.

Pharmacology

Pharmacodynamics

Amitriptyline inhibits serotonin transporter (SERT) and norepinephrine transporter (NET). It is metabolised to nortriptyline, a stronger norepinephrine reuptake inhibitor, further augmenting amitriptyline’s effects on norepinephrine reuptake.

Amitriptyline additionally acts as a potent inhibitor of the serotonin 5-HT2A, 5-HT2C, the α1A-adrenergic, the histamine H1 and the M1-M5 muscarinic acetylcholine receptors.

Amitriptyline is a non-selective blocker of multiple ion channels, in particular, voltage-gated sodium channels Nav1.3, Nav1.5, Nav1.6, Nav1.7, and Nav1.8, voltage-gated potassium channels Kv7.2/ Kv7.3, Kv7.1, Kv7.1/KCNE1, and hERG.

Mechanism of Action

Inhibition of serotonin and norepinephrine transporters by amitriptyline results in interference with neuronal reuptake of serotonin and norepinephrine. Since the reuptake process is important physiologically in terminating transmitting activity, this action may potentiate or prolong activity of serotonergic and adrenergic neurons and is believed to underlie the antidepressant activity of amitriptyline.

Inhibition of norepinephrine reuptake leading to increased concentration of norepinephrine in the posterior grey column of the spinal cord appears to be mostly responsible for the analgesic action of amitriptyline. Increased level of norepinephrine increases the basal activity of alpha-2 adrenergic receptors, which mediate an analgesic effect by increasing gamma-aminobutyric acid transmission among spinal interneurons. The blocking effect of amitriptyline on sodium channels may also contribute to its efficacy in pain conditions.

Pharmacokinetics

Amitriptyline is readily absorbed from the gastrointestinal tract (90-95%). Absorption is gradual with the peak concentration in blood plasma reached after about 4 hours. Extensive metabolism on the first pass through the liver leads to average bioavailability of about 50% (45%-53%). Amitriptyline is metabolized mostly by CYP2C19 into nortriptyline and by CYP2D6 leading to a variety of hydroxylated metabolites, with the principal one among them being (E)-10-hydroxynortriptyline, and to a lesser degree, by CYP3A4.

Nortriptyline, the main active metabolite of amitriptyline, is an antidepressant on its own right. Nortriptyline reaches 10% higher level in the blood plasma than the parent drug amitriptyline and 40% greater area under the curve, and its action is an important part of the overall action of amitriptyline.

Another active metabolite is (E)-10-hydroxynortriptyline, which is a norepinephrine uptake inhibitor four times weaker than nortriptyline. (E)-10-hydroxynortiptyline blood level is comparable to that of nortriptyline, but its cerebrospinal fluid level, which is a close proxy of the brain concentration of a drug, is twice higher than nortriptyline’s. Based on this, (E)-10-hydroxynortriptyline was suggested to significantly contribute to antidepressant effects of amitriptyline.

Blood levels of amitriptyline and nortriptyline and pharmacokinetics of amitriptyline in general, with clearance difference of up to 10-fold, vary widely between individuals. Variability of the area under the curve in steady state is also high, which makes a slow upward titration of the dose necessary.

In the blood, amitriptyline is 96% bound to plasma proteins; nortriptyline is 93-95% bound, and (E)-10-hydroxynortiptyline is about 60% bound. Amitriptyline has an elimination half life of 21 hours, nortriptyline – 23-31 hours, and (E)-10-hydroxynortiptyline – 8-10 hours. Within 48 hours, 12-80% of amitriptyline is eliminated in the urine, mostly as metabolites. 2% of the unchanged drug is excreted in the urine. Elimination in the faeces, apparently, have not been studied.

Therapeutic levels of amitriptyline range from 75 to 175 ng/mL (270-631 nM), or 80-250 ng/mL of both amitriptyline and its metabolite nortriptyline.

Pharmacogenetics

Since amitriptyline is primarily metabolised by CYP2D6 and CYP2C19, genetic variations within the genes coding for these enzymes can affect its metabolism, leading to changes in the concentrations of the drug in the body. Increased concentrations of amitriptyline may increase the risk for side effects, including anticholinergic and nervous system adverse effects, while decreased concentrations may reduce the drug’s efficacy.

Individuals can be categorised into different types of CYP2D6 or CYP2C19 metabolisers depending on which genetic variations they carry. These metaboliser types include poor, intermediate, extensive, and ultrarapid metabolisers. Most individuals (about 77-92%) are extensive metabolisers, and have “normal” metabolism of amitriptyline. Poor and intermediate metabolisers have reduced metabolism of the drug as compared to extensive metabolisers; patients with these metaboliser types may have an increased probability of experiencing side effects. Ultrarapid metabolisers use amitriptyline much faster than extensive metabolisers; patients with this metaboliser type may have a greater chance of experiencing pharmacological failure.

The Clinical Pharmacogenetics Implementation Consortium recommends avoiding amitriptyline in patients who are CYP2D6 ultrarapid or poor metabolizers, due to the risk for a lack of efficacy and side effects, respectively. The consortium also recommends considering an alternative drug not metabolised by CYP2C19 in patients who are CYP2C19 ultrarapid metabolisers. A reduction in starting dose is recommended for patients who are CYP2D6 intermediate metabolisers and CYP2C19 poor metabolisers. If use of amitriptyline is warranted, therapeutic drug monitoring is recommended to guide dose adjustments. The Dutch Pharmacogenetics Working Group also recommends selecting an alternative drug or monitoring plasma concentrations of amitriptyline in patients who are CYP2D6 poor or ultrarapid metabolisers, and selecting an alternative drug or reducing initial dose in patients who are CYP2D6 intermediate metabolisers.

Chemistry

Amitriptyline is a highly lipophilic molecule having an octanol-water partition coefficient (pH 7.4) of 3.0, while the log P of the free base was reported as 4.92. Solubility of the free base amitriptyline in water is 14 mg/L. Amitriptyline is prepared by reacting dibenzosuberone with 3-(dimethylamino)propylmagnesium chloride and then heating the resulting intermediate product with hydrochloric acid to eliminate water.

Society and Culture

English folk singer Nick Drake died from an overdose of Tryptizol in 1974.

Senteni Masango, wife of Swaziland King Mswati, died on 6 April 2018 after committing suicide by overdosing on amytriptyline capsules.

In the 2021 film The Many Saints of Newark, amitriptyline (referred to by the brand name Elavil) is part of the plot line of the movie.

Generic Names

Amitriptyline is the English and French generic name of the drug and its INN, BAN, and DCF, while amitriptyline hydrochloride is its USAN, USP, BANM, and JAN. Its generic name in Spanish and Italian and its DCIT are amitriptilina, in German is Amitriptylin, and in Latin is amitriptylinum. The embonate salt is known as amitriptyline embonate, which is its BANM, or as amitriptyline pamoate unofficially.

This page is based on the copyrighted Wikipedia article < https://en.wikipedia.org/wiki/Amitriptyline >; it is used under the Creative Commons Attribution-ShareAlike 3.0 Unported License (CC-BY-SA). You may redistribute it, verbatim or modified, providing that you comply with the terms of the CC-BY-SA.

What is Sertraline?

Published on by Andrew Marshall1 Comment

Introduction

Sertraline, sold under the brand name Zoloft among others, is an antidepressant of the selective serotonin reuptake inhibitor (SSRI) class.

The efficacy of sertraline for depression is similar to that of other antidepressants, and the differences are mostly confined to side effects. Sertraline is better tolerated than the older tricyclic antidepressants, and it may work better than fluoxetine for some subtypes of depression. Sertraline is effective for panic disorder, social anxiety disorder, generalised anxiety disorder (GAD), and obsessive-compulsive disorder (OCD). However, for OCD, cognitive behavioural therapy (CBT), particularly in combination with sertraline, is a better treatment. Although approved for post-traumatic stress disorder, sertraline leads to only modest improvement in this condition. Sertraline also alleviates the symptoms of premenstrual dysphoric disorder and can be used in sub-therapeutic doses or intermittently for its treatment.

Sertraline shares the common side effects and contraindications of other SSRIs, with high rates of nausea, diarrhoea, insomnia, and sexual side effects, but it appears not to lead to much weight gain, and its effects on cognitive performance are mild. Similar to other antidepressants, the use of sertraline for depression may be associated with a higher rate of suicidal thoughts and behaviour in people under the age of 25. It should not be used together with MAO inhibitor medication: this combination causes serotonin syndrome. Sertraline taken during pregnancy is associated with a significant increase in congenital heart defects in newborns.

Sertraline was invented and developed by scientists at Pfizer and approved for medical use in the United States in 1991. It is on the World Health Organisation’s List of Essential Medicines. It is available as a generic medication. In 2016, sertraline was the most commonly prescribed psychiatric medication in the US and in 2019, it was the twelfth most commonly prescribed medication in the US, with over 37 million prescriptions.

Brief History

The history of sertraline dates back to the early 1970s, when Pfizer chemist Reinhard Sarges invented a novel series of psychoactive compounds, including lometraline, based on the structures of the neuroleptics thiothixene and pinoxepin. Further work on these compounds led to tametraline, a norepinephrine and weaker dopamine reuptake inhibitor. Development of tametraline was soon stopped because of undesired stimulant effects observed in animals. A few years later, in 1977, pharmacologist Kenneth Koe, after comparing the structural features of a variety of reuptake inhibitors, became interested in the tametraline series. He asked another Pfizer chemist, Willard Welch, to synthesize some previously unexplored tametraline derivatives. Welch generated a number of potent norepinephrine and triple reuptake inhibitors, but to the surprise of the scientists, one representative of the generally inactive cis-analogues was a serotonin reuptake inhibitor. Welch then prepared stereoisomers of this compound, which were tested in vivo by animal behavioural scientist Albert Weissman. The most potent and selective (+)-isomer was taken into further development and eventually named sertraline. Weissman and Koe recalled that the group did not set up to produce an antidepressant of the SSRI type – in that sense their inquiry was not “very goal driven”, and the discovery of the sertraline molecule was serendipitous. According to Welch, they worked outside the mainstream at Pfizer, and even “did not have a formal project team”. The group had to overcome initial bureaucratic reluctance to pursue sertraline development, as Pfizer was considering licensing an antidepressant candidate from another company.

Sertraline was approved by the US Food and Drug Administration (FDA) in 1991 based on the recommendation of the Psychopharmacological Drugs Advisory Committee; it had already become available in the United Kingdom the previous year. The FDA committee achieved a consensus that sertraline was safe and effective for the treatment of major depression. During the discussion, Paul Leber, the director of the FDA Division of Neuropharmacological Drug Products, noted that granting approval was a “tough decision”, since the treatment effect on outpatients with depression had been “modest to minimal”. Other experts emphasized that the drug’s effect on inpatients had not differed from placebo and criticised poor design of the clinical trials by Pfizer. For example, 40% of participants dropped out of the trials, significantly decreasing their validity.

Until 2002, sertraline was only approved for use in adults ages 18 and over; that year, it was approved by the FDA for use in treating children aged 6 or older with severe OCD. In 2003, the UK Medicines and Healthcare products Regulatory Agency issued a guidance that, apart from fluoxetine (Prozac), SSRIs are not suitable for the treatment of depression in patients under 18. However, sertraline can still be used in the UK for the treatment of OCD in children and adolescents. In 2005, the FDA added a boxed warning concerning paediatric suicidal behaviour to all antidepressants, including sertraline. In 2007, labelling was again changed to add a warning regarding suicidal behaviour in young adults ages 18 to 24.

Medical Uses

Sertraline has been approved for major depressive disorder (MDD), obsessive-compulsive disorder (OCD), posttraumatic stress disorder (PTSD), premenstrual dysphoric disorder (PMDD), panic disorder, and social anxiety disorder (SAD). Sertraline is not approved for use in children except for those with OCD.

Depression

Multiple controlled clinical trials established efficacy of sertraline for the treatment of depression. Sertraline is also an effective antidepressant in the routine clinical practice. Continued treatment with sertraline prevents both a relapse of the current depressive episode and future episodes (recurrence of depression).

In several double-blind studies, sertraline was consistently more effective than placebo for dysthymia, a more chronic variety of depression, and comparable to imipramine in that respect. Sertraline also improves the depression of dysthymic patients to a greater degree than psychotherapy.

Limited paediatric data also demonstrates reduction in depressive symptoms in the paediatric population though remains a second line therapy after fluoxetine.

Comparison with Other Antidepressants

In general, sertraline efficacy is similar to that of other antidepressants. For example, a meta-analysis of 12 new-generation antidepressants showed that sertraline and escitalopram are the best in terms of efficacy and acceptability in the acute-phase treatment of adults with depression. Comparative clinical trials demonstrated that sertraline is similar in efficacy against depression to moclobemide, nefazodone, escitalopram, bupropion, citalopram, fluvoxamine, paroxetine, venlafaxine, and mirtazapine. Sertraline may be more efficacious for the treatment of depression in the acute phase (first 4 weeks) than fluoxetine.

There are differences between sertraline and some other antidepressants in their efficacy in the treatment of different subtypes of depression and in their adverse effects. For severe depression, sertraline is as good as clomipramine but is better tolerated. Sertraline appears to work better in melancholic depression than fluoxetine, paroxetine, and mianserin and is similar to the tricyclic antidepressants such as amitriptyline and clomipramine. In the treatment of depression accompanied by OCD, sertraline performs significantly better than desipramine on the measures of both OCD and depression. Sertraline is equivalent to imipramine for the treatment of depression with co-morbid panic disorder, but it is better tolerated. Compared with amitriptyline, sertraline offered a greater overall improvement in quality of life of depressed patients.

Depression in Elderly

Sertraline used for the treatment of depression in elderly (older than 60) patients is superior to placebo and comparable to another SSRI fluoxetine, and tricyclic antidepressants (TCAs) amitriptyline, nortriptyline and imipramine. Sertraline has much lower rates of adverse effects than these TCAs, with the exception of nausea, which occurs more frequently with sertraline. In addition, sertraline appears to be more effective than fluoxetine or nortriptyline in the older-than-70 subgroup. Accordingly, a meta-analysis of antidepressants in older adults found that sertraline, paroxetine and duloxetine were better than placebo. On the other hand, in a 2003 trial the effect size was modest, and there was no improvement in quality of life as compared to placebo. With depression in dementia, there is no benefit of sertraline treatment compared to either placebo or mirtazapine.

Obsessive-Compulsive Disorder

Sertraline is effective for the treatment of OCD in adults and children. It was better tolerated and, based on intention-to-treat analysis, performed better than the gold standard of OCD treatment clomipramine. Continuing sertraline treatment helps prevent relapses of OCD with long-term data supporting its use for up to 24 months. It is generally accepted that the sertraline dosages necessary for the effective treatment of OCD are higher than the usual dosage for depression. The onset of action is also slower for OCD than for depression. The treatment recommendation is to start treatment with a half of maximal recommended dose for at least two months. After that, the dose can be raised to the maximal recommended in the cases of unsatisfactory response.

CBT alone was superior to sertraline in both adults and children; however, the best results were achieved using a combination of these treatments.

Panic Disorder

Sertraline is superior to placebo for the treatment of panic disorder. The response rate was independent of the dose. In addition to decreasing the frequency of panic attacks by about 80% (vs. 45% for placebo) and decreasing general anxiety, sertraline resulted in improvement of quality of life on most parameters. The patients rated as “improved” on sertraline reported better quality of life than the ones who “improved” on placebo. The authors of the study argued that the improvement achieved with sertraline is different and of a better quality than the improvement achieved with placebo. Sertraline is equally effective for men and women, and for patients with or without agoraphobia. Previous unsuccessful treatment with benzodiazepines does not diminish its efficacy. However, the response rate was lower for the patients with more severe panic. Starting treatment simultaneously with sertraline and clonazepam, with subsequent gradual discontinuation of clonazepam, may accelerate the response.

Double-blind comparative studies found sertraline to have the same effect on panic disorder as paroxetine or imipramine. While imprecise, comparison of the results of trials of sertraline with separate trials of other anti-panic agents (clomipramine, imipramine, clonazepam, alprazolam, and fluvoxamine) indicates approximate equivalence of these medications.

Other Anxiety Disorders

Sertraline has been successfully used for the treatment of social anxiety disorder. All three major domains of the disorder (fear, avoidance, and physiological symptoms) respond to sertraline. Maintenance treatment, after the response is achieved, prevents the return of the symptoms. The improvement is greater among the patients with later, adult onset of the disorder. In a comparison trial, sertraline was superior to exposure therapy, but patients treated with the psychological intervention continued to improve during a year-long follow-up, while those treated with sertraline deteriorated after treatment termination. The combination of sertraline and CBT appears to be more effective in children and young people than either treatment alone.

Sertraline has not been approved for the treatment of generalised anxiety disorder; however, several guidelines recommend it as a first-line medication referring to good quality controlled clinical trials.

Premenstrual Dysphoric Disorder

Sertraline is effective in alleviating the symptoms of premenstrual dysphoric disorder (PMDD), a severe form of premenstrual syndrome. Significant improvement was observed in 50-60% of cases treated with sertraline vs. 20-30% of cases on placebo. The improvement began during the first week of treatment, and in addition to mood, irritability, and anxiety, improvement was reflected in better family functioning, social activity and general quality of life. Work functioning and physical symptoms, such as swelling, bloating and breast tenderness, were less responsive to sertraline. Taking sertraline only during the luteal phase, that is, the 12-14 days before menses, was shown to work as well as continuous treatment. Continuous treatment with sub-therapeutic doses of sertraline (25 mg vs. usual 50-100 mg) is also effective.

Other Indications

Sertraline is approved for the treatment of post-traumatic stress disorder (PTSD). National Institute of Clinical Excellence recommends it for patients who prefer drug treatment to a psychological one. Other guidelines also suggest sertraline as a first-line option for pharmacological therapy. When necessary, long-term pharmacotherapy can be beneficial. There are both negative and positive clinical trial results for sertraline, which may be explained by the types of psychological traumas, symptoms, and comorbidities included in the various studies. Positive results were obtained in trials that included predominantly women (75%) with a majority (60%) having physical or sexual assault as the traumatic event. Contrary to the above suggestions, a meta-analysis of sertraline clinical trials for PTSD found it to be not significantly better than placebo. Another meta-analysis relegated sertraline to the second line, proposing trauma focused psychotherapy as a first-line intervention. The authors noted that Pfizer had declined to submit the results of a negative trial for the inclusion into the meta-analysis making the results unreliable.

Sertraline when taken daily can be useful for the treatment of premature ejaculation. A disadvantage of sertraline is that it requires continuous daily treatment to delay ejaculation significantly.

A 2019 systematic review suggested that sertraline may be a good way to control anger, irritability and hostility in depressed patients and patients with other comorbidities.

Contraindications

Sertraline is contraindicated in individuals taking monoamine oxidase inhibitors or the antipsychotic pimozide. Sertraline concentrate contains alcohol and is therefore contraindicated with disulfiram. The prescribing information recommends that treatment of the elderly and patients with liver impairment “must be approached with caution”. Due to the slower elimination of sertraline in these groups, their exposure to sertraline may be as high as three times the average exposure for the same dose.

Side Effects

Nausea, ejaculation failure, insomnia, diarrhoea, dry mouth, somnolence, dizziness, tremor, headache, excessive sweating, fatigue, and decreased libido are the common adverse effects associated with sertraline with the greatest difference from placebo. Those that most often resulted in interruption of the treatment are nausea, diarrhoea and insomnia. The incidence of diarrhoea is higher with sertraline – especially when prescribed at higher doses – in comparison with other SSRIs.

Over more than six months of sertraline therapy for depression, people showed a nonsignificant weight increase of 0.1%. Similarly, a 30-month-long treatment with sertraline for OCD resulted in a mean weight gain of 1.5% (1 kg). Although the difference did not reach statistical significance, the average weight gain was lower for fluoxetine (1%) but higher for citalopram, fluvoxamine and paroxetine (2.5%). Of the sertraline group, 4.5% gained a large amount of weight (defined as more than 7% gain). This result compares favourably with placebo, where, according to the literature, 3-6% of patients gained more than 7% of their initial weight. The large weight gain was observed only among female members of the sertraline group; the significance of this finding is unclear because of the small size of the group.

Over a two-week treatment of healthy volunteers, sertraline slightly improved verbal fluency but did not affect word learning, short-term memory, vigilance, flicker fusion time, choice reaction time, memory span, or psychomotor coordination. In spite of lower subjective rating, that is, feeling that they performed worse, no clinically relevant differences were observed in the objective cognitive performance in a group of people treated for depression with sertraline for 1.5 years as compared to healthy controls. In children and adolescents taking sertraline for six weeks for anxiety disorders, 18 out of 20 measures of memory, attention and alertness stayed unchanged. Divided attention was improved and verbal memory under interference conditions decreased marginally. Because of the large number of measures taken, it is possible that these changes were still due to chance. The unique effect of sertraline on dopaminergic neurotransmission may be related to these effects on cognition and vigilance.

Sertraline has a low level of exposure of an infant through the breast milk and is recommended as the preferred option for the antidepressant therapy of breast-feeding mothers. There is 29-42% increase in congenital heart defects among children whose mothers were prescribed sertraline during pregnancy, with sertraline use in the first trimester associated with 2.7-fold increase in septal heart defects.

Abrupt interruption of sertraline treatment may result in withdrawal or discontinuation syndrome. Dizziness, insomnia, anxiety, agitation, and irritability are its common symptoms. It typically occurs within a few days from drug discontinuation and lasts a few weeks. The withdrawal symptoms for sertraline are less severe and frequent than for paroxetine, and more frequent than for fluoxetine. In most cases symptoms are mild, short-lived, and resolve without treatment. More severe cases are often successfully treated by temporary reintroduction of the drug with a slower tapering off rate.

Sertraline and SSRI antidepressants in general may be associated with bruxism and other movement disorders. Sertraline appears to be associated with microscopic colitis, a rare condition of unknown aetiology.

Sexual

Like other SSRIs, sertraline is associated with sexual side effects, including sexual arousal disorder, erectile dysfunction and difficulty achieving orgasm. While nefazodone and bupropion do not have negative effects on sexual functioning, 67% of men on sertraline experienced ejaculation difficulties versus 18% before the treatment. Sexual arousal disorder, defined as “inadequate lubrication and swelling for women and erectile difficulties for men”, occurred in 12% of people on sertraline as compared with 1% of patients on placebo. The mood improvement resulting from the treatment with sertraline sometimes counteracted these side effects, so that sexual desire and overall satisfaction with sex stayed the same as before the sertraline treatment. However, under the action of placebo the desire and satisfaction slightly improved. Some people continue experiencing sexual side effects after they stop taking SSRIs.

Suicide

The US Food and Drug Administration (FDA) requires all antidepressants, including sertraline, to carry a boxed warning stating that antidepressants increase the risk of suicide in persons younger than 25 years. This warning is based on statistical analyses conducted by two independent groups of FDA experts that found a 100% increase of suicidal thoughts and behaviour in children and adolescents, and a 50% increase – in the 18-24 age group.

Suicidal ideation and behaviour in clinical trials are rare. For the above analysis, the FDA combined the results of 295 trials of 11 antidepressants for psychiatric indications in order to obtain statistically significant results. Considered separately, sertraline use in adults decreased the odds of suicidal behaviour with a marginal statistical significance by 37% or 50% depending on the statistical technique used. The authors of the FDA analysis note that “given the large number of comparisons made in this review, chance is a very plausible explanation for this difference”. The more complete data submitted later by the sertraline manufacturer Pfizer indicated increased suicidal behaviour. Similarly, the analysis conducted by the UK Medicines and Healthcare Products Regulatory Agency (MHRA) found a 50% increase of odds of suicide-related events, not reaching statistical significance, in the patients on sertraline as compared to the ones on placebo.

Overdose

Acute overdosage is often manifested by emesis, lethargy, ataxia, tachycardia and seizures. Plasma, serum or blood concentrations of sertraline and norsertraline, its major active metabolite, may be measured to confirm a diagnosis of poisoning in hospitalised patients or to aid in the medicolegal investigation of fatalities. As with most other SSRIs its toxicity in overdose is considered relatively low.

Interactions

As with other SSRIs, sertraline may increase the risk of bleeding with NSAIDs (non-steroidal anti-inflammatory drugs such as ibuprofen, naproxen, mefenamic acid), antiplatelet drugs, anticoagulants, omega-3 fatty acids, vitamin E, and garlic supplements due to sertraline’s inhibitory effects on platelet aggregation via blocking serotonin transporters on platelets. Sertraline, in particular, may potentially diminish the efficacy of levothyroxine.

Sertraline is a moderate inhibitor of CYP2D6 and CYP2B6 in vitro. Accordingly, in human trials it caused increased blood levels of CYP2D6 substrates such as metoprolol, dextromethorphan, desipramine, imipramine and nortriptyline, as well as the CYP3A4/CYP2D6 substrate haloperidol. This effect is dose-dependent; for example, co-administration with 50 mg of sertraline resulted in 20% greater exposure to desipramine, while 150 mg of sertraline led to a 70% increase. In a placebo-controlled study, the concomitant administration of sertraline and methadone caused a 40% increase in blood levels of the latter, which is primarily metabolized by CYP2B6.

Sertraline had a slight inhibitory effect on the metabolism of diazepam, tolbutamide and warfarin, which are CYP2C9 or CYP2C19 substrates; the clinical relevance of this effect was unclear. As expected from in vitro data, sertraline did not alter the human metabolism of the CYP3A4 substrates erythromycin, alprazolam, carbamazepine, clonazepam, and terfenadine; neither did it affect metabolism of the CYP1A2 substrate clozapine.

Sertraline had no effect on the actions of digoxin and atenolol, which are not metabolised in the liver. Case reports suggest that taking sertraline with phenytoin or zolpidem may induce sertraline metabolism and decrease its efficacy, and that taking sertraline with lamotrigine may increase the blood level of lamotrigine, possibly by inhibition of glucuronidation.

CYP2C19 inhibitor esomeprazole increased sertraline concentrations in blood plasma by approximately 40%.

Clinical reports indicate that interaction between sertraline and the MAOIs isocarboxazid and tranylcypromine may cause serotonin syndrome. In a placebo-controlled study in which sertraline was co-administered with lithium, 35% of the subjects experienced tremors, while none of those taking placebo did.

Sertraline may interact with grapefruit juice.

Pharmacology

Pharmacodynamics

Sertraline is a selective serotonin reuptake inhibitor (SSRI). By binding serotonin transporter (SERT) it inhibits neuronal reuptake of serotonin and potentiates serotonergic activity in the central nervous system. Over time, this leads to a downregulation of pre-synaptic 5-HT1A receptors, which is associated with an improvement in passive stress tolerance, and delayed downstream increase in expression of brain-derived neurotrophic factor (BDNF), which may contribute to a reduction in negative affective biases. It does not significantly affect norepinephrine transporter (NET), serotonin, dopamine, adrenergic, histamine, acetylcholine, GABA or benzodiazepine receptors.

Sertraline also shows relatively high activity as an inhibitor of the dopamine transporter (DAT) and antagonist of the sigma σ1 receptor (but not the σ2 receptor). However, sertraline affinity for its main target (SERT) is much greater than its affinity for σ1 receptor and DAT. Although there could be a role for the σ1 receptor in the pharmacology of sertraline, the significance of this receptor in its actions is unclear. Similarly, the clinical relevance of sertraline’s blockade of the dopamine transporter is uncertain.

Pharmacokinetics

Absorption

Following a single oral dose of sertraline, mean peak blood levels of sertraline occur between 4.5 and 8.4 hours. Bioavailability is likely linear and dose-proportional over a dose range of 150 to 200 mg. Concomitant intake of sertraline with food slightly increases sertraline peak levels and total exposure. There is an approximate 2-fold accumulation of sertraline with continuous administration and steady-state levels are reached within one week.

Distribution

Sertraline is highly plasma protein bound (98.5%) across a concentration range of 20 to 500 ng/mL. Despite the high plasma protein binding, sertraline and its metabolite desmethylsertraline at respective tested concentrations of 300 ng/mL and 200 ng/mL were found not to interfere with the plasma protein binding of warfarin and propranolol, two other highly plasma protein-bound drugs.

Metabolism

Sertraline is subject to extensive first-pass metabolism, as indicated by a small study of radiolabelled sertraline in which less than 5% of plasma radioactivity was unchanged sertraline in two males. The principal metabolic pathway for sertraline is N-demethylation into desmethylsertraline (N-desmethylsertraline) mainly by CYP2B6. Reduction, hydroxylation, and glucuronide conjugation of both sertraline and desmethylsertraline also occur. Desmethylsertraline, while pharmacologically active, is substantially (50-fold) weaker than sertraline as a serotonin reuptake inhibitor and its influence on the clinical effects of sertraline is thought to be negligible. Based on in vitro studies, sertraline is metabolized by multiple cytochrome 450 isoforms; however, it appears that in the human body CYP2C19 plays the most important role, followed by CYP2B6. In addition to the cytochrome P450 system, sertraline can be oxidatively deaminated in vitro by monoamine oxidases; however, this metabolic pathway has never been studied in vivo.

Elimination

The elimination half-life of sertraline is on average 26 hours, with a range of 13 to 45 hours. The half-life of sertraline is longer in women (32 hours) than in men (22 hours), which leads to 1.5-fold higher exposure to sertraline in women compared to men. The elimination half-life of desmethylsertraline is 62 to 104 hours.

In a small study of two males, sertraline was excreted to similar degrees in urine and faeces (40 to 45% each within 9 days). Unchanged sertraline was not detectable in urine, whereas 12 to 14% unchanged sertraline was present in faeces.

Pharmacogenomics

CYP2C19 and CYP2B6 are thought to be the key cytochrome P450 enzymes involved in the metabolism of sertraline. Relative to CYP2C19 normal (extensive) metabolisers, poor metabolisers have 2.7-fold higher levels of sertraline and intermediate metabolisers have 1.4-fold higher levels. In contrast, CYP2B6 poor metabolisers have 1.6-fold higher levels of sertraline and intermediate metabolisers have 1.2-fold higher levels.

Society and Culture

Generic Availability

The US patent for Zoloft expired in 2006, and sertraline is available in generic form and is marketed under many brand names worldwide.

In May 2020, the FDA placed Zoloft on the list of drugs currently facing a shortage.

Other Uses

Lass-Flörl et al., 2003 finds sertraline significantly inhibits phospholipase B in the fungal genus Candida, reducing virulence. It is also a very effective leishmanicide. Specifically, Palit & Ali 2008 find that sertraline kills almost all promastigotes of Leishmania donovani.

This page is based on the copyrighted Wikipedia article < https://en.wikipedia.org/wiki/Sertraline >; it is used under the Creative Commons Attribution-ShareAlike 3.0 Unported License (CC-BY-SA). You may redistribute it, verbatim or modified, providing that you comply with the terms of the CC-BY-SA.

What is Amineptine?

Published on by Andrew MarshallLeave a comment

Introduction

Amineptine, formerly sold under the brand name Survector among others, is an atypical antidepressant of the tricyclic antidepressant (TCA) family.

It acts as a selective and mixed dopamine reuptake inhibitor and releasing agent, and to a lesser extent as a norepinephrine reuptake inhibitor.

Amineptine was developed by the French Society of Medical research in the 1960s. Introduced in France in 1978 by the pharmaceutical company Servier, amineptine soon gained a reputation for abuse due to its short-lived, but pleasant, stimulant effect experienced by some patients.

After its release into the European market, cases of hepatotoxicity emerged, some serious. This, along with the potential for abuse, led to the suspension of the French marketing authorization for Survector in 1999.

Amineptine was never approved by the US Food and Drug Administration (FDA) for marketing in the US, meaning that it is not legal to market or sell amineptine for any medical uses in the US.

Medical Uses

Amineptine was approved in France for severe clinical depression of endogenous origin in 1978.

Contraindications

  • Chorea
  • Hypersensitivity: Known hypersensitivity to amineptine, in particular antecedents of hepatitis after dosage of the product.
  • MAO inhibitors.

Precautions for Use

Warnings and precautions before taking amineptine:

  • Breast feeding.
  • Children less than 15-year of age.
  • General anaesthesia: Discontinue the drug 24 to 48 hours before anaesthesia.
  • Official sports/Olympic Games: Prohibited substance.
  • Pregnancy (first trimester).

Effects on the Foetus

  • Lacking information in humans.
  • Non-teratogenic in rodents.

Side Effects

Dermatological

Severe acne due to amineptine was first reported in 1988 by various authors – Grupper, Thioly-Bensoussan, Vexiau, Fiet, Puissant, Gourmel, Teillac, Levigne, to name a few – simultaneously in the same issue of Annales de dermatologie et de vénéréologie and in the 12 March 1988 issue of The Lancet. A year later, Dr Martin-Ortega and colleagues in Barcelona, Spain reported a case of “acneiform eruption” in a 54-year-old woman whose intake of amineptine was described as “excessive.” One year after that, Vexiau and colleagues reported six women, one of whom never admitted to using amineptine, getting severe acne concentrated in the face, back and thorax, the severity of which varied with the dosage. Most of them were treated unsuccessfully with isotretinoin (Accutane) for about 18 months; two of the three that discontinued amineptine experienced a reduction in cutaneous symptoms, with the least affected patient going into remission.

Psychiatric

Psychomotor excitation can very rarely occur with this drug.

  • Insomnia.
  • Irritability.
  • Nervousness.
  • Suicidal ideation. Seen early in the treatment, by lifting of psychomotor inhibition.

Abuse and Dependence

The risk of addiction is low, but exists nonetheless. Between 1978 and 1988, there were 186 cases of amineptine addiction reported to the French Regional Centres of Pharmacovigilance; an analysis of 155 of those cases found that they were predominantly female, and that two-thirds of cases had known risk factors for addiction. However, a 1981 study of known opiate addicts and schizophrenia patients found no drug addiction in any of the subjects. In a 1990 study of eight amineptine dependence cases, the gradual withdrawal of amineptine could be achieved without problems in six people; in two others, anxiety, psychomotor agitation, and/or bulimia appeared.

Withdrawal

Pharmacodependence is very common with amineptine compared to other antidepressants. A variety of psychological symptoms can occur during withdrawal from amineptine, such as anxiety and agitation.

Cardiovascular

Very rarely:

  • Arterial hypotension.
  • Palpitations.
  • Vasomotor episode.

Hepatic

Amineptine can rarely cause hepatitis, of the cytolytic, cholestatic varieties. Amineptine-induced hepatitis, which is sometimes preceded by a rash, is believed to be due to an immunoallergic reaction. It resolves upon discontinuation of the offending drug. The risk of getting this may or may not be genetically determined.

Additionally, amineptine is known to rarely elevate transaminases, alkaline phosphatase, and bilirubin.

Mixed hepatitis, which is very rare, generally occurs between the 15th and 30th day of treatment. Often preceded by sometimes intense abdominal pains, nausea, vomiting or a rash, the jaundice is variable. Hepatitis is either of mixed type or with cholestatic prevalence. The evolution was, in all the cases, favourable to the discontinuation of the drug. The mechanism is discussed (immunoallergic and/or toxic).

In circa 1994 Spain, there was a case associating acute pancreatitis and mixed hepatitis, after three weeks of treatment.

Lazaros and colleagues at the Western Attica General Hospital in Athens, Greece reported two cases of drug induced hepatitis 18 and 15 days of treatment.

One case of cytolytic hepatitis occurred after ingestion of only one tablet.

Gastrointestinal

Acute pancreatitis (very rare) A case associating acute pancreatitis and mixed hepatitis after three weeks of treatment.

Immunological

In 1989, Sgro and colleagues at the Centre de Pharmacovigilance in Dijon reported a case of anaphylactic shock in a woman who had been taking amineptine.

Pharmacology

Pharmacodynamics

Amineptine inhibits the reuptake of dopamine and, to a much lesser extent, of norepinephrine. In addition, it has been found to induce the release of dopamine. However, amineptine is much less efficacious as a dopamine releasing agent relative to D-amphetamine, and the drug appears to act predominantly as a dopamine reuptake inhibitor. In contrast to the case for dopamine, amineptine does not induce the release of norepinephrine, and hence acts purely as a norepinephrine reuptake inhibitor. Unlike other TCAs, amineptine interacts very weakly or not at all with the serotonin, adrenergic, dopamine, histamine, and muscarinic acetylcholine receptors. The major metabolites of amineptine have similar activity to that of the parent compound, albeit with lower potency.

No human data appear to be available for binding or inhibition of the monoamine transporters by amineptine.

Pharmacokinetics

Peak plasma levels of amineptine following a single 100 mg oral dose have been found to range between 277 and 2,215 ng/mL (818-6,544 nM), with a mean of 772 ng/mL (2,281 nM), whereas maximal plasma concentrations of its major metabolite ranged between 144 and 1,068 ng/mL (465–3,452 nM), with a mean of 471 ng/mL (1,522 nM). After a single 200 mg oral dose of amineptine, mean peak plasma levels of amineptine were around 750 to 940 ng/mL (2,216-2,777 nM), while those of its major metabolite were about 750 to 970 ng/mL (2,216-3,135 nM). The time to peak concentrations is about 1 hour for amineptine and 1.5 hours for its major metabolite. The elimination half-life of amineptine is about 0.80 to 1.0 hours and that of its major metabolite is about 1.5 to 2.5 hours. Due to their very short elimination half-lives, amineptine and its major metabolite do not accumulate significantly with repeated administration.

Society and Culture

Brand Names

Amineptine has been sold under a variety of brand names including Survector, Maneon, Directim, Neolior, Provector, and Viaspera.

Legal Status

It had been proposed that Amineptine become a Schedule I controlled substance in the United States in July 2021.

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What is Clomipramine?

Published on by Andrew Marshall5 Comments

Introduction

Clomipramine, sold under the brand name Anafranil among others, is a tricyclic antidepressant (TCA).

It is used for the treatment of obsessive-compulsive disorder (OCD), panic disorder, major depressive disorder (MDD), and chronic pain. It may increase the risk of suicide in those under the age of 25. It is taken by mouth. It has also been used to treat premature ejaculation.

Common side effects include dry mouth, constipation, loss of appetite, sleepiness, weight gain, sexual dysfunction, and trouble urinating. Serious side effects include an increased risk of suicidal behaviour in those under the age of 25, seizures, mania, and liver problems. If stopped suddenly a withdrawal syndrome may occur with headaches, sweating, and dizziness. It is unclear if it is safe for use in pregnancy. Its mechanism of action is not entirely clear but is believed to involve increased levels of serotonin.

Clomipramine was discovered in 1964 by the Swiss drug manufacturer Ciba-Geigy. It is on the World Health Organisation’s List of Essential Medicines. It is available as a generic medication.

Brief History

Clomipramine was developed by Geigy as a chlorinated derivative of Imipramine. It was first referenced in the literature in 1961 and was patented in 1963. The drug was first approved for medical use in Europe in the treatment of depression in 1970, and was the last of the major TCAs to be marketed. In fact, clomipramine was initially considered to be a “me-too drug” by the FDA, and in relation to this, was declined licensing for depression in the United States. As such, to this day, clomipramine remains the only TCA that is available in the United States that is not approved for the treatment of depression, in spite of the fact that it is a highly effective antidepressant. Clomipramine was eventually approved in the United States for the treatment of OCD in 1989 and became available in 1990. It was the first drug to be investigated and found effective in the treatment of OCD. The first reports of benefits in OCD were in 1967, and the first double-blind, placebo-controlled clinical trial of clomipramine for OCD was conducted in 1976, with more rigorous clinical studies that solidified its effectiveness conducted in the 1980s. It remained the “gold standard” for the treatment of OCD for many years until the introduction of the SSRIs, which have since largely superseded it due to greatly improved tolerability and safety (although notably not effectiveness). Clomipramine is the only TCA that has been shown to be effective in the treatment of OCD and that is approved by the US Food and Drug Administration (FDA) for the treatment of OCD; the other TCAs failed clinical trials for this indication, likely due to insufficient serotonergic activity.

Medical Uses

Clomipramine has a number of uses in medicine including in the treatment of:

  • OCD which is its only US Food and Drug Administration (FDA)-labelled indication. Other regulatory agencies (such as the TGA of Australia and the MHRA of the UK) have also approved clomipramine for this indication.
  • MDD a popular off-label use in the US. It is approved by the Australian TGA and the United Kingdom MHRA for this indication. Some have suggested the possible superior efficacy of clomipramine compared to other antidepressants in the treatment of MDD, although at the current time the evidence is insufficient to adequately substantiate this claim.
  • Panic disorder with or without agoraphobia.
  • Body dysmorphic disorder.
  • Cataplexy associated with narcolepsy. Which is a TGA and MHRA-labelled indication for clomipramine.
  • Premature ejaculation.
  • Depersonalisation disorder.
  • Chronic pain with or without organic disease, particularly headache of the tension type.
  • Sleep paralysis, with or without narcolepsy.
  • Enuresis (involuntary urinating in sleep) in children. The effect may not be sustained following treatment, and alarm therapy may be more effective in both the short-term and the long-term. Combining a tricyclic (such as clomipramine) with anticholinergic medication, may be more effective for treating enuresis than the tricyclic alone.
  • Trichotillomania.

In a meta-analysis of various trials involving fluoxetine (Prozac), fluvoxamine (Luvox), and sertraline (Zoloft) to test their relative efficacies in treating OCD, clomipramine was found to be the most effective.

Contraindications

Contraindications include:

  • Known hypersensitivity to clomipramine, or any of the excipients or cross-sensitivity to tricyclic antidepressants of the dibenzazepine group.
  • Recent myocardial infarction.
  • Any degree of heart block or other cardiac arrhythmias.
  • Mania.
  • Severe liver disease.
  • Narrow angle glaucoma.
  • Urinary retention.
  • It must not be given in combination or within 3 weeks before or after treatment with a monoamine oxidase inhibitor (Moclobemide included, however clomipramine can be initiated sooner at 48 hours following discontinuation of moclobemide).

Pregnancy and Lactation

Clomipramine use during pregnancy is associated with congenital heart defects in the newborn. It is also associated with reversible withdrawal effects in the newborn. Clomipramine is also distributed in breast milk and hence nursing while taking clomipramine is advised against.

Side Effects

Clomipramine has been associated with the following side effects:

  • Very common (>10% frequency):
    • Accommodation defect.
    • Blurred vision.
    • Nausea.
    • Dry mouth (Xerostomia).
    • Constipation.
    • Fatigue.
    • Weight gain.
    • Increased appetite.
    • Dizziness.
    • Tremor.
    • Headache.
    • Myoclonus.
    • Drowsiness.
    • Somnolence.
    • Restlessness.
    • Micturition disorder.
    • Sexual dysfunction (erectile dysfunction and loss of libido).
    • Hyperhidrosis (profuse sweating).
  • Common (1-10% frequency):
    • Weight loss.
    • Orthostatic hypotension.
    • Sinus tachycardia.
    • Clinically irrelevant ECG changes (e.g. T- and ST-wave changes) in patients of normal cardiac status.
    • Palpitations.
    • Tinnitus (hearing ringing in one’s ears).
    • Mydriasis (dilated pupils).
    • Vomiting.
    • Abdominal disorders.
    • Diarrhoea.
    • Decreased appetite.
    • Increased transaminases.
    • Increased Alkaline phosphatase.
    • Speech disorders.
    • Paraesthesia.
    • Muscle hypertonia.
    • Dysgeusia.
    • Memory impairment.
    • Muscular weakness.
    • Disturbance in attention.
    • Confusional state.
    • Disorientation.
    • Hallucinations (particularly in elderly patients and patients with Parkinson’s disease).
    • Anxiety.
    • Agitation.
    • Sleep disorders.
    • Mania.
    • Hypomania.
    • Aggression.
    • Depersonalisation.
    • Insomnia.
    • Nightmares.
    • Aggravation of depression.
    • Delirium.
    • Galactorrhoea (lactation that is not associated with pregnancy or breastfeeding).
    • Breast enlargement.
    • Yawning.
    • Hot flush.
    • Dermatitis allergic (skin rash, urticaria).
    • Photosensitivity reaction.
    • Pruritus (itching).
  • Uncommon (0.1-1% frequency):
    • Convulsions.
    • Ataxia.
    • Arrhythmias.
    • Elevated blood pressure.
    • Activation of psychotic symptoms.
  • Very rare (<0.01% frequency):
    • Pancytopaenia: An abnormally low amount of all the different types of blood cells in the blood (including platelets, white blood cells and red blood cells).
    • Leukopenia: A low white blood cell count.
    • Agranulocytosis: A more severe form of leukopenia; a dangerously low neutrophil count which leaves one open to life-threatening infections due to the role of the white blood cells in defending the body from invaders.
    • Thrombocytopenia: An abnormally low amount of platelets in the blood which are essential to clotting and hence this leads to an increased tendency to bruise and bleed, including, potentially, internally.
    • Eosinophilia: An abnormally high number of eosinophils – the cells that fight off parasitic infections – in the blood.
    • Syndrome of inappropriate secretion of antidiuretic hormone (SIADH): A potentially fatal reaction to certain medications that is due to an excessive release of antidiuretic hormone – a hormone that prevents the production of urine by increasing the reabsorption of fluids in the kidney – this results in the development of various electrolyte abnormalities (e.g. hyponatraemia [low blood sodium], hypokalaemia [low blood potassium], hypocalcaemia [low blood calcium]).
    • Glaucoma.
    • Oedema (local or generalised).
    • Alopecia (hair loss).
    • Hyperpyrexia (a high fever that is above 41.5 °C).
    • Hepatitis (liver swelling) with or without jaundice: The yellowing of the eyes, the skin, and mucous membranes due to impaired liver function.
    • Abnormal ECG.
    • Anaphylactic and anaphylactoid reactions including hypotension.
    • Neuroleptic malignant syndrome (NMS): A potentially fatal side effect of antidopaminergic agents such as antipsychotics, tricyclic antidepressants and antiemetics (drugs that relieve nausea and vomiting). NMS develops over a period of days or weeks and is characterised by the following symptoms:
      • Tremor.
      • Muscle rigidity.
      • Mental status change (such as confusion, delirium, mania, hypomania, agitation, coma, etc.).
      • Hyperthermia (high body temperature).
      • Tachycardia (high heart rate).
      • Blood pressure changes.
      • Diaphoresis (sweating profusely).
      • Diarrhoea.
    • Alveolitis allergic (pneumonitis) with or without eosinophilia.
    • Purpura.
    • Conduction disorder (e.g. widening of QRS complex, prolonged QT interval, PR/PQ interval changes, bundle-branch block, torsade de pointes, particularly in patients with hypokalaemia).

Withdrawal

Withdrawal symptoms may occur during gradual or particularly abrupt withdrawal of tricyclic antidepressant drugs. Possible symptoms include: nausea, vomiting, abdominal pain, diarrhoea, insomnia, headache, nervousness, anxiety, dizziness and worsening of psychiatric status. Differentiating between the return of the original psychiatric disorder and clomipramine withdrawal symptoms is important. Clomipramine withdrawal can be severe. Withdrawal symptoms can also occur in neonates when clomipramine is used during pregnancy. A major mechanism of withdrawal from tricyclic antidepressants is believed to be due to a rebound effect of excessive cholinergic activity due to neuroadaptations as a result of chronic inhibition of cholinergic receptors by tricyclic antidepressants. Restarting the antidepressant and slow tapering is the treatment of choice for tricyclic antidepressant withdrawal. Some withdrawal symptoms may respond to anticholinergics, such as atropine or benztropine mesylate.

Overdose

Refer to Tricyclic Antidepressant Overdose.

Clomipramine overdose usually presents with the following symptoms:

  • Signs of central nervous system depression such as:
    • Stupor.
    • Coma.
    • Drowsiness.
    • Restlessness.
    • Ataxia.
  • Mydriasis.
  • Convulsions.
  • Enhanced reflexes.
  • Muscle rigidity.
  • Athetoid and choreoathetoid movements.
  • Serotonin syndrome: A condition with many of the same symptoms as neuroleptic malignant syndrome but has a significantly more rapid onset.
  • Cardiovascular effects including:
    • Arrhythmias (including Torsades de pointes).
    • Tachycardia.
    • QTc interval prolongation.
    • Conduction disorders.
    • Hypotension.
    • Shock.
    • Heart failure.
    • Cardiac arrest.
  • Apnoea.
  • Cyanosis.
  • Respiratory depression.
  • Vomiting.
  • Fever.
  • Sweating.
  • Oliguria.
  • Anuria.

There is no specific antidote for overdose and all treatment is purely supportive and symptomatic. Treatment with activated charcoal may be used to limit absorption in cases of oral overdose. Anyone suspected of overdosing on clomipramine should be hospitalised and kept under close surveillance for at least 72 hours. Clomipramine has been reported as being less toxic in overdose than most other TCAs in one meta-analysis but this may well be due to the circumstances surrounding most overdoses as clomipramine is more frequently used to treat conditions for which the rate of suicide is not particularly high such as OCD. In another meta-analysis, however, clomipramine was associated with a significant degree of toxicity in overdose.

Interactions

Clomipramine may interact with a number of different medications, including the monoamine oxidase inhibitors which include isocarboxazid, moclobemide, phenelzine, selegiline and tranylcypromine, antiarrhythmic agents (due to the effects of TCAs like clomipramine on cardiac conduction. There is also a potential pharmacokinetic interaction with quinidine due to the fact that clomipramine is metabolised by CYP2D6 in vivo), diuretics (due to the potential for hypokalaemia (low blood potassium) to develop which increases the risk for QT interval prolongation and torsades de pointes), the selective serotonin reuptake inhibitors (SSRIs; due to both potential additive serotonergic effects leading to serotonin syndrome and the potential for a pharmacokinetic interaction with the SSRIs that inhibit CYP2D6 [e.g. fluoxetine and paroxetine]) and serotonergic agents such as triptans, other tricyclic antidepressants, tramadol, etc. (due to the potential for serotonin syndrome). Its use is also advised against in those concurrently on CYP2D6 inhibitors due to the potential for increased plasma levels of clomipramine and the resulting potential for CNS and cardiotoxicity.

Pharmacology

Pharmacodynamics

Clomipramine is a reuptake inhibitor of serotonin and norepinephrine, or a serotonin-norepinephrine reuptake inhibitor (SNRI); that is, it blocks the reuptake of these neurotransmitters back into neurons by preventing them from interacting with their transporters, thereby increasing their extracellular concentrations in the synaptic cleft and resulting in increased serotonergic and noradrenergic neurotransmission. In addition, clomipramine also has antiadrenergic, antihistamine, antiserotonergic, antidopaminergic, and anticholinergic activities. It is specifically an antagonist of the α1-adrenergic receptor, the histamine H1 receptor, the serotonin 5-HT2A, 5-HT2C, 5-HT3, 5-HT6, and 5-HT7 receptors, the dopamine D1, D2, and D3 receptors, and the muscarinic acetylcholine receptors (M1-M5). Like other TCAs, clomipramine weakly blocks voltage-dependent sodium channels as well.

Although clomipramine shows around 100- to 200-fold preference in affinity for the serotonin transporter (SERT) over the norepinephrine transporter (NET), its major active metabolite, desmethylclomipramine (norclomipramine), binds to the NET with very high affinity (Ki = 0.32 nM) and with dramatically reduced affinity for the SERT (Ki = 31.6 nM). Moreover, desmethylclomipramine circulates at concentrations that are approximately twice those of clomipramine. In accordance, occupancy of both the SERT and the NET has been shown with clomipramine administration in positron emission tomography studies with humans and non-human primates. As such, clomipramine is in fact a fairly balanced SNRI rather than only a serotonin reuptake inhibitor (SRI).

The antidepressant effects of clomipramine are thought to be due to reuptake inhibition of serotonin and norepinephrine, while serotonin reuptake inhibition only is thought to be responsible for the effectiveness of clomipramine in the treatment of OCD. Conversely, antagonism of the H1, α1-adrenergic, and muscarinic acetylcholine receptors is thought to contribute to its side effects. Blockade of the H1 receptor is specifically responsible for the antihistamine effects of clomipramine and side effects like sedation and somnolence (sleepiness). Antagonism of the α1-adrenergic receptor is thought to cause orthostatic hypotension and dizziness. Inhibition of muscarinic acetylcholine receptors is responsible for the anticholinergic side effects of clomipramine like dry mouth, constipation, urinary retention, blurred vision, and cognitive/memory impairment. In overdose, sodium channel blockade in the brain is believed to cause the coma and seizures associated with TCAs while blockade of sodium channels in the heart is considered to cause cardiac arrhythmias, cardiac arrest, and death. On the other hand, sodium channel blockade is also thought to contribute to the analgesic effects of TCAs, for instance in the treatment of neuropathic pain.

The exceptionally strong serotonin reuptake inhibition of clomipramine likely precludes the possibility of its antagonism of serotonin receptors (which it binds to with more than 100-fold lower affinity than the SERT) resulting in a net decrease in signalling by these receptors. In accordance, while serotonin receptor antagonists like cyproheptadine and chlorpromazine are effective as antidotes against serotonin syndrome, clomipramine is nonetheless capable of inducing this syndrome. In fact, while all TCAs are SRIs and serotonin receptor antagonists to varying extents, the only TCAs that are associated with serotonin syndrome are clomipramine and to a lesser extent its dechlorinated analogue imipramine, which are the two most potent SRIs of the TCAs (and in relation to this have the highest ratios of serotonin reuptake inhibition to serotonin receptor antagonism). As such, whereas other TCAs can be combined with monoamine oxidase inhibitors (with caution due to the risk of hypertensive crisis from NET inhibition; sometimes done in treatment-resistant depressives), clomipramine cannot be due to the risk of serotonin syndrome and death. Unlike the case of its serotonin receptor antagonism, orthostatic hypotension is a common side effect of clomipramine, suggesting that its blockade of the α1-adrenergic receptor is strong enough to overcome the stimulatory effects on the α1-adrenergic receptor of its NET inhibition.

Serotonergic Activity

Clomipramine is a very strong SRI. Its affinity for the SERT was reported in one study using human tissues to be 0.14 nM, which is considerably higher than that of other TCAs. For example, the TCAs with the next highest affinities for the SERT in the study were imipramine, amitriptyline, and dosulepin (dothiepin), with Ki values of 1.4 nM, 4.3 nM, and 8.3 nM, respectively. In addition, clomipramine has a terminal half-life that is around twice as long as that of amitriptyline and imipramine. In spite of these differences however, clomipramine is used clinically at the same usual dosages as other serotonergic TCAs (100-200 mg/day). It achieves typical circulating concentrations that are similar in range to those of other TCAs but with an upper limit that is around twice that of amitriptyline and imipramine. For these reasons, clomipramine is the most potent SRI among the TCAs and is far stronger as an SRI than other TCAs at typical clinical dosages. In addition, clomipramine is more potent as an SRI than any SSRIs, it is more potent than paroxetine, which is the strongest SSRI.

A positron emission tomography study found that a single low dose of 10 mg clomipramine to healthy volunteers resulted in 81.1% occupancy of the SERT, which was comparable to the 84.9% SERT occupancy by 50 mg fluvoxamine. In the study, single doses of 5 to 50 mg clomipramine resulted in 67.2 to 94.0% SERT occupancy while single doses of 12.5 to 50 mg fluvoxamine resulted in 28.4 to 84.9% SERT occupancy. Chronic treatment with higher doses was able to achieve up to 100.0% SERT occupancy with clomipramine and up to 93.6% SERT occupancy with fluvoxamine. Other studies have found 83% SERT occupancy with 20 mg/day paroxetine and 77% SERT occupancy with 20 mg/day citalopram. These results indicate that very low doses of clomipramine are able to substantially occupy the SERT and that clomipramine achieves higher occupancy of the SERT than SSRIs at comparable doses. Moreover, clomipramine may be able to achieve more complete occupancy of the SERT at high doses, at least relative to fluvoxamine.

If the ratios of the 80% SERT occupancy dosage and the approved clinical dosage range are calculated and compared for SSRIs, SNRIs, and clomipramine, it can be deduced that clomipramine is by far the strongest SRI used medically. The lowest approved dosage of clomipramine can be estimated to be roughly comparable in SERT occupancy to the maximum approved dosages of the strongest SSRIs and SNRIs. Because their mechanism of action was originally not known and dose-ranging studies were never conducted, first-generation antipsychotics were dramatically overdosed in patients. It has been suggested that the same may have been true for clomipramine and other TCAs.

Obsessive-Compulsive Disorder

Clomipramine was the first drug that was investigated for and found to be effective in the treatment of OCD. In addition, it was the first drug to be approved by the Food and Drug Administration (FDA) in the United States for the treatment of OCD. The effectiveness of clomipramine in the treatment of OCD is far greater than that of other TCAs, which are comparatively weak SRIs; a meta-analysis found pre- versus post-treatment effect sizes of 1.55 for clomipramine relative to a range of 0.67 for imipramine and 0.11 for desipramine. In contrast to other TCAs, studies have found that clomipramine and SSRIs, which are more potent SRIs, have similar effectiveness in the treatment of OCD. However, multiple meta-analyses have found that clomipramine nonetheless retains a significant effectiveness advantage relative to SSRIs; in the same meta-analysis mentioned previously, the effect sizes of SSRIs in the treatment of OCD ranged from 0.81 for fluoxetine to 1.36 for sertraline (relative to 1.55 for clomipramine). However, the effectiveness advantage for clomipramine has not been apparent in head-to-head comparisons of clomipramine versus SSRIs for OCD. The differences in effectiveness findings could be due to differences in methodologies across non-head-to-head studies.

Relatively high doses of SSRIs are needed for effectiveness in the treatment of OCD. Studies have found that high dosages of SSRIs above the normally recommended maximums are significantly more effective in OCD treatment than lower dosages (e.g. 250 to 400 mg/day sertraline versus 200 mg/day sertraline). In addition, the combination of clomipramine and SSRIs has also been found to be significantly more effective in alleviating OCD symptoms, and clomipramine is commonly used to augment SSRIs for this reason. Studies have found that intravenous clomipramine, which is associated with very high circulating concentrations of the drug and a much higher ratio of clomipramine to its metabolite desmethylclomipramine, is more effective than oral clomipramine in the treatment of OCD. There is a case report of complete remission from OCD for approximately one month following a massive overdose of fluoxetine, an SSRI with a uniquely long duration of action. Taken together, stronger serotonin reuptake inhibition has consistently been associated with greater alleviation of OCD symptoms, and since clomipramine, at the clinical dosages in which it is employed, is effectively the strongest SRI used medically, this may underlie its unique effectiveness in the treatment of OCD.

In addition to serotonin reuptake inhibition, clomipramine is also a mild but clinically significant antagonist of the dopamine D1, D2, and D3 receptors at high concentrations. Addition of antipsychotics, which are potent dopamine receptor antagonists, to SSRIs, has been found to significantly augment their effectiveness in the treatment of OCD. As such, besides strong serotonin reuptake inhibition, clomipramine at high doses might also block dopamine receptors to treat OCD symptoms, and this could additionally or alternatively be involved in its possible effectiveness advantage over SSRIs.

Although clomipramine is probably more effective in the treatment of OCD compared to SSRIs, it is greatly inferior to them in terms of tolerability and safety due to its lack of selectivity for the SERT and promiscuous pharmacological activity. In addition, clomipramine has high toxicity in overdose and can potentially result in death, whereas death rarely, if ever, occurs with overdose of SSRIs. It is for these reasons that clomipramine, in spite of potentially superior effectiveness to SSRIs, is now rarely used as a first-line agent in the treatment of OCD, with SSRIs being used as first-line therapies instead and clomipramine generally being reserved for more severe cases and as a second-line agent.

Pharmacokinetics

The oral bioavailability of clomipramine is approximately 50%. Peak plasma concentrations occur around 2-6 hours (with an average of 4.7 hours) after taking clomipramine orally and are in the range of 56-154 ng/mL (178-489 nmol/L). Steady-state concentrations of clomipramine are around 134-532 ng/mL (426-1,690 nmol/L), with an average of 218 ng/mL (692 nmol/L), and are reached after 7 to 14 days of repeated dosing. Steady-state concentrations of the active metabolite, desmethylclomipramine, are around 230-550 ng/mL (730-1,750 nmol/L). The volume of distribution (Vd) of clomipramine is approximately 17 L/kg. It binds approximately 97-98% to plasma proteins, primarily to albumin. Clomipramine is metabolised in the liver mainly by CYP2D6. It has a terminal half-life of 32 hours, and its N-desmethyl metabolite, desmethylclomipramine, has a terminal half-life of approximately 69 hours. Clomipramine is mostly excreted in urine (60%) and faeces (32%).

Chemistry

Clomipramine is a tricyclic compound, specifically a dibenzazepine, and possesses three rings fused together with a side chain attached in its chemical structure. Other dibenzazepine TCAs include imipramine, desipramine, and trimipramine. Clomipramine is a derivative of imipramine with a chlorine atom added to one of its rings and is also known as 3-chloroimipramine. It is a tertiary amine TCA, with its side chain-demethylated metabolite desmethylclomipramine being a secondary amine. Other tertiary amine TCAs include amitriptyline, imipramine, dosulepin (dothiepin), doxepin, and trimipramine. The chemical name of clomipramine is 3-(3-chloro-10,11-dihydro-5H-dibenzo[b,f]azepin-5-yl)-N,N-dimethylpropan-1-amine and its free base form has a chemical formula of C19H23ClN2 with a molecular weight of 314.857 g/mol. The drug is used commercially almost exclusively as the hydrochloride salt; the free base has been used rarely. The CAS Registry Number of the free base is 303-49-1 and of the hydrochloride is 17321-77-6.

Society and Culture

Generic Names

Clomipramine is the English and French generic name of the drug and its INN, BAN, and DCF, while clomipramine hydrochloride is its USAN, USP, BANM, and JAN. Clomipramina is its generic name in Spanish, Portuguese and Italian and its DCIT, while clomipramin is its generic name in German and clomipraminum is its generic name in Latin.

Brand Names

Clomipramine is marketed throughout the world mainly under the brand names Anafranil and Clomicalm for use in humans and animals, respectively.

Veterinary Uses

In the US, clomipramine is only licensed to treat separation anxiety in dogs for which it is sold under the brand name Clomicalm. It has proven effective in the treatment of OCD in cats and dogs. In dogs, it has also demonstrated similar efficacy to fluoxetine in treating tail chasing. In dogs some evidence suggests its efficacy in treating noise phobia.

Clomipramine has also demonstrated efficacy in treating urine spraying in cats. Various studies have been done on the effects of clomipramine on cats to reduce urine spraying/marking behaviour. It has been shown to be able to reduce this behaviour by up to 75% in a trial period of four weeks.

What is an Atypical Antidepressant?

Published on by Andrew Marshall3 Comments

Introduction

An atypical antidepressant is any antidepressant medication that acts in a manner that is different from that of most other antidepressants.

Refer to Second-Generation Antidepressant, Tricyclic Antidepressant, and Tetracyclic Antidepressant.

Background

Atypical antidepressants include agomelatine, bupropion, mianserin, mirtazapine, nefazodone, opipramol, tianeptine, and trazodone. The agents vilazodone and vortioxetine are partly atypical. Typical antidepressants include the SSRIs, SNRIs, TCAs, and MAOIs, which act mainly by increasing the levels of the monoamine neurotransmitters serotonin and/or norepinephrine. Among TCAs, trimipramine is an atypical agent in that it appears not to do this. In August 2020, Esketamine (JNJ-54135419) was approved by the US Food and Drug Administration (FDA) for the treatment for treatment-resistant depression with the added indication for the short-term treatment of suicidal thoughts.

Buprenorphine/Samidorphan (ALKS-5461) is an antidepressant with a novel mechanism of action which is under development and is considered an atypical antidepressant. They act faster than available antidepressants.

What is a Second-Generation Antidepressant?

Published on by Andrew Marshall1 Comment

Introduction

The second-generation antidepressants are a class of antidepressants characterised primarily by the era of their introduction, approximately coinciding with the 1970s and 1980s, rather than by their chemical structure or by their pharmacological effect. As a consequence, there is some controversy over which treatments actually belong in this class.

Refer to Atypical Antidepressant, Tricyclic Antidepressant, and Tetracyclic Antidepressant.

The term “third generation antidepressant” is sometimes used to refer to newer antidepressants, from the 1990s and 2000s, often selective serotonin reuptake inhibitors (SSRIs) such as; fluoxetine (Prozac), paroxetine (Paxil) and sertraline (Zoloft), as well as some non-SSRI antidepressants such as mirtazapine, nefazodone, venlafaxine, duloxetine and reboxetine. However, this usage is not universal.

Examples

This list is not exhaustive, and different sources vary upon which items should be considered second-generation.

  • Amineptine.
  • Amoxapine.
  • Bupropion.
  • Iprindole.
  • Maprotiline.
  • Medifoxamine.
  • Mianserin.
  • Nomifensine.
  • Tianeptine.
  • Trazodone.
  • Venlafaxine.
  • Viloxazine.

What is Maprotiline?

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Introduction

Maprotiline, sold under the brand name Ludiomil among others, is a tetracyclic antidepressant (TeCA) that is used in the treatment of depression.

It may alternatively be classified as a tricyclic antidepressant (TCA), specifically a secondary amine. In terms of its chemistry and pharmacology, maprotiline is closely related to other secondary amine TCAs like nortriptyline and protriptyline, and has similar effects to them.

Brief History

Maprotiline was developed by Ciba (now operated by Novartis). It was patented in 1966 and was first described in the literature in 1969. The drug was introduced for medical use in 1974. Generics are now widely available. It was introduced after most of the other TCAs but was the first TeCA to be developed and marketed, with the TeCAs mianserin and amoxapine following shortly thereafter and mirtazapine being introduced later on.

Medical Uses

Maprotiline is used in the treatment of depression, such as depression associated with agitation or anxiety and has similar efficacy to the antidepressant drug moclobemide.

  • Treatment of depression of all forms and severities (endogenous, psychotic, involutional, and neurotic) especially for depression associated with agitation or anxiety.
  • Panic disorder.
  • Neuropathic pain.
  • Treatment of the depressive phase in bipolar depression.
  • For the symptomatic relief of anxiety, tension or insomnia.

The use of maprotiline in the treatment of enuresis in paediatric patients has so far not been systematically explored and its use is not recommended. Safety and effectiveness in the paediatric population in general have not been established. Anyone considering the use of maprotiline in a child or adolescent must balance the potential risks with the clinical need. In general, lower dosages are recommended for patients over 60 years of age. Dosages of 50 mg to 75 mg daily are usually satisfactory as maintenance therapy for elderly patients who do not tolerate higher amounts.[8][9]

Available Forms

  • Coated Tablets, 10 mg, 25 mg, 50 mg, and 75 mg.
  • Injectable concentrate, 25 mg.

Contraindications

Maprotiline may worsen psychotic conditions like schizophrenia and should be given with caution. The antipsychotic treatment should be continued. Patients with bipolar affective disorder should not receive antidepressants whilst in a manic phase, as antidepressants can worsen mania.

Absolute

  • Hypersensitivity to maprotiline or to other TCAs and TeCAs.
  • Hypertrophy of the prostate gland with urine hesitancy.
  • Closed angle glaucoma.

Special Caution Needed

  • Concomitant treatment with a MAO inhibitor.
  • Serious impairment of liver and kidney function.
  • Epilepsy and other conditions that lower the seizure threshold (active brain tumours, alcohol withdrawal, other medications).
  • Serious cardiovascular conditions (arrhythmias, heart insufficience, state after myocardial infarction etc.).
  • Treatment of patients under age 18.

Suicidal Patients

Same as other antidepressants, maprotiline increased the risk compared to placebo of suicidal thinking and behaviour (suicidality) in children, adolescents and young adults in short-term studies of major depressive disorder (MDD) and other psychiatric disorders. Anyone considering the use of maprotiline or any other antidepressant in a child, adolescent, or young adult must balance this risk with the clinical need. Short-term studies did not show an increase in the risk of suicidality with antidepressants compared to placebo in adults beyond age 24; there was a reduction in risk with antidepressants compared to placebo in adults aged 65 and older. Depression and certain other psychiatric disorders are themselves associated with increases in the risk of suicide. Patients of all ages who are started on antidepressant therapy should be monitored appropriately and observed closely for clinical worsening, suicidality, or unusual changes in behaviour. Families and caregivers should be advised of the need for close observation and communication with the prescriber. Maprotiline is not approved for use in paediatric patients.

Pregnancy and Lactation

Reproduction studies have been performed in female laboratory rabbits, mice, and rats at doses up to 1.3, 7, and 9 times the maximum daily human dose respectively and have revealed no evidence of impaired fertility or harm to the foetus due to maprotiline. There are, however, no adequate and well controlled studies in pregnant women. Because animal reproduction studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed.

Maprotiline is excreted in breast milk. At steady-state, the concentrations in milk correspond closely to the concentrations in whole blood. Caution should be exercised when maprotiline hydrochloride is administered to a nursing woman.

Side Effects

The side-effect profile is comparable to other TCAs and TeCAS and many of the following are due to anticholinergic (which are less prominent than those of most TCAs) and antihistamine effects. Most often seen are:

  • Dizziness.
  • Drowsiness.
  • Somnolence.
  • Fatigue.
  • Dry mouth (and complications of long-term uncontrolled dry mouth such as dental caries).
  • Constipation.
  • Vertigo.
  • Nausea (rare, incidence of ~2%) and vomiting.
  • Increased appetite and weight gain.
  • Orthostatic hypotension, hypertension, sinus tachycardia, heart-block, arrhythmias and other cardiac effects.
  • Sexual dysfunction in men: impotence, priapism, delayed ejaculation, anejaculation, decreased libido.
  • Sexual dysfunction in women: decreased libido, vaginal dryness, painful sexual intercourse, anorgasmia.
  • Allergic skin reactions such as rash or urticaria (more often than with other antidepressants).
    • Rarely, severe skin reactions such as erythema multiforme can occur.
  • Photosensitivity.
  • Agitation, confusion.
  • Induction of hypomania or mania in patients suffering from underlying bipolar affective disorder.
  • Psychotic symptoms.
  • Tremor.
  • Extrapyramidal symptoms.
  • Headache.
  • Seizures (at high doses).
  • Rare haematological complications: leukopenia and agranulocytosis (dangerous fall in white blood cells).
  • Fever.
  • Urinary retention.

Maprotiline causes a strong initial sedation (first 2 to 3 weeks of therapy) and is therefore indicated to treat agitated patients or those with suicidal risks. It causes anticholinergic side effects (dry mouth, constipation, confusion, tachycardia) with a lower incidence than amitriptyline. Originally, the manufacturer claimed that maprotiline is better tolerated than other TCAs and TeCAs. However, seizures, leukopenia and skin reactions occur more often with maprotiline than with comparable drugs like amitriptyline.

Maprotiline has no known potential for abuse and psychological dependence.

Withdrawal

Withdrawal symptoms frequently seen when treatment with maprotiline is stopped abruptly (agitation, anxiety, insomnia, sometimes activation of mania or rebound depression) are not indicative of addiction and can be avoided by reducing the daily dose of maprotiline gradually by approximately 25% each week. If treatment has to be stopped at once due to medical reasons, the use of a benzodiazepine (e.g. lorazepam, clonazepam, or alprazolam) for a maximum of 4 weeks as needed will usually suppress withdrawal symptoms.

Interactions

Maprotiline has a wide range of possible interactions. Some are typical for TCAs and TeCAs, others are caused by specific metabolic effects (e.g. high plasma-protein-binding) of maprotiline:

  • Irreversible MAO-inhibitors: agitation, delirium, coma, hyperpyrexia (high fever), seizures and severe changes in blood pressure.
  • Treatment-resistant and hospitalised patients may be treated concomitantly with an MAO-inhibitor, if they are closely monitored and if the initial dose of the MAO-Inhibitor is low.

Increased Drug Actions

  • Other antidepressants, barbiturates, narcotics, sedating antihistamines, anticonvulsive drugs, alcohol, resulting in increased central depression.
  • Anticholinergics (antiparkinsonian agents, TCAs and TeCAs) – resulting in increased anticholinergic action (dry mouth, constipation etc.).
  • Sympathomimetics (also those used in local anaesthetics like noradrenaline):
    • Sympathomimetic effects increased (increased blood pressure, pulse rate, paleness of skin etc.)
  • Nitrates and anti-hypertensives (e.g. beta-blockers), increased antihypertensive action with pronounced fall in blood pressure.

Decreased Drug Actions

  • Guanethidine, Reserpine, Guanfacine : antihypertensive effects decreased.
  • Clonidine: antihypertensive effects decreased and risk of (massive) rebound hypertension.

Other Types of Interaction

  • Drugs, which induce certain enzymes in the liver, e.g. barbiturates, phenytoin, carbamazepine and oral anti-conceptive drugs, enhance the elimination of maprotiline and decrease its antidepressant effects.
    • Additionally the blood-concentrations of phenytoin or carbamazepine may be increased, leading to a higher incidents of side effects.
  • The concomitant use of maprotiline and neuroleptics can lead to increased maprotiline blood-levels and to seizures.
    • Combining maprotiline and thioridazine could induce severe arrhythmias.
  • Additionally, increased blood-levels of Maprotiline are possible, if certain beta-blocking agents (e.g. Propranolol) are given concomitantly.
  • Maprotiline may amplify the actions of coumarin-type anticoagulants (e.g. warfarin, phenprocoumon).
    • The plasma-prothrombin-activity must be assessed closely in order to avoid overt bleedings.
  • Maprotiline can increase the actions of oral antidiabetic drugs (sulfonylureas) and Insulin.
    • Diabetic patients should have regular assessments of their blood-glucose-levels.
  • The concomitant application with fluoxetine or fluvoxamine may lead to significantly increased plasma-levels of maprotiline with a high incidence of maprotiline side effects.
    • Due to the long half-lives of fluoxetine and fluvoxamine this effect may persist.

Pharmacology

Pharmacodynamics

Maprotiline exhibits strong effects as a norepinephrine reuptake inhibitor with only weak actions the reuptake of serotonin and dopamine. It is also a strong antagonist of the H1 receptor, a moderate antagonist of the 5-HT2 and α1-adrenergic receptors, and a weak antagonist of the D2 and muscarinic acetylcholine receptors. Maprotiline has also more recently been identified as a potent antagonist of the 5-HT7 receptor, with this action potentially playing an important role in its antidepressant effectiveness. The drug is a strong antihistamine, but unlike most TCAs, has minimal anticholinergic effects.

The pharmacological profile of maprotiline explains its antidepressant, sedative, anxiolytic, and sympathomimetic activities. In accordance to the pharmacological characteristics it is used in the treatment of depression, such as depression associated with agitation or anxiety. Additionally, it shows strong antagonism against reserpine-induced effects in animal studies, as do the other ‘classical’ antidepressants. Although maprotiline behaves in most regards as a ‘first-generation antidepressant’ it is commonly referred to as ‘second-generation antidepressant’.

The postulated mechanism of maprotiline is that it acts primarily by potentiation of central adrenergic synapses by blocking reuptake of norepinephrine at nerve endings. This pharmacological action is thought to be primarily responsible for the drug’s antidepressant and anxiolytic effects. It is a strong norepinephrine reuptake inhibitor with only weak effects on serotonin and dopamine reuptake. At higher doses however, maprotiline increases serotonergic transmission and increases the level of serotonin available.

Pharmacokinetics

After oral use absorption is good. It binds to plasma proteins 80-90%. Maximal plasma concentration is reached 6 hours after use. The mean time to peak is 12 hours. The terminal half-life of averages 51 hours.

Chemistry

Maprotiline is a tetracyclic compound and is grouped with the TeCAs. Its chemical name is N-methyl-9,10-ethanoanthracen-9(10H)-propylamine. The drug has a dibenzobicyclo[2.2.2]octadiene (9,10-dihydro-9,10-ethanoanthracene) ring system; that is, a tricyclic anthracene ring system with an ethylene bridge across the central ring. This results in it having a unique three-dimensional central ring (a bicyclo[2.2.2]octane or 1,4-endoethylenecyclohexane ring) and being a tetracyclic rather than a tricyclic compound. However, it could also or alternatively be considered to be a tricyclic and hence a TCA. In addition to its heterocyclic ring system, maprotiline has an alkylamine side chain attached similarly to other TCAs (but notably unlike other TeCAs). In terms of the side chain, it is a secondary amine, and its chemical structure, aside from the ethylene link in the central ring, is similar to that of secondary amine TCAs like nortriptyline and protriptyline. In accordance, the pharmacology of maprotiline is very similar to that of secondary amine TCAs.

Maprotiline is very similar in structure to the anxiolytic, sedative, and muscle relaxant drug benzoctamine (Tacitin). The only structural difference between the two compounds is in the length of their side chain. However, this modification results in considerable differences in their pharmacological and therapeutic effects.

Society and Culture

Generic Names

Maprotiline is the English and French generic name of the drug and its INN, USAN, BAN, and DCF, while maprotiline hydrochloride is its USAN, USP, BANM and JAN. Its generic name in Spanish and Italian and its DCIT are maprotilina, in German is maprotilin, and in Latin is maprotilinum. The methanesulfonate (mesylate) salt is known unofficially as maprotiline methanesulfonate.

Brand Names

Maprotiline is marketed throughout the world mainly under the brand name Ludiomil. It is also available under a variety of other brand names including Deprilept, Maprolu, and Psymion among others.

What is Melitracen?

Published on by Andrew Marshall1 Comment

Introduction

Melitracen (brand names Melixeran) is a tricyclic antidepressant (TCA), for the treatment of depression and anxiety.

Refer to Flupentixol/Melitracen.

Background

In addition to single drug preparations, it is also available as Deanxit, marketed by Lundbeck, a combination product containing both melitracen and flupentixol.

The pharmacology of melitracen has not been properly investigated and is largely unknown, but it is likely to act in a similar manner to other TCAs. Indeed, melitracen is reported to have imipramine and amitriptyline-like effects and efficacy against depression and anxiety, though with improved tolerability and a somewhat faster onset of action.