Tag: Benzodiazepine

What is Clorazepate?

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Introduction

Clorazepate, sold under the brand name Tranxene among others, is a benzodiazepine medication. It possesses anxiolytic, anticonvulsant, sedative, hypnotic, and skeletal muscle relaxant properties. Clorazepate is an unusually long-lasting benzodiazepine and serves as a majoritive prodrug for the equally long-lasting desmethyldiazepam, which is rapidly produced as an active metabolite. Desmethyldiazepam is responsible for most of the therapeutic effects of clorazepate.

It was patented in 1965 and approved for medical use in 1967.

Medical Uses

Clorazepate is used in the treatment of anxiety disorders and insomnia. It may also be prescribed as an anticonvulsant or muscle relaxant. It is also used as a premedication.

Clorazepate is prescribed principally in the treatment of alcohol withdrawal and epilepsy, although it is also a useful anxiolytic because of its long half-life. The normal starting dosage range of Clorazepate is 15 to 60 mg per day. The drug is to be taken two to four times per day. Dosages as high as 90 to 120 mg per day may be used in the treatment of acute alcohol withdrawal. In the United States and Canada, Clorazepate is available in 3.75, 7.5, and 15 mg capsules or tablets. In Europe, tablet formations are 5 mg, 10 mg, 20 mg and 50 mg. Clorazepate SD (controlled release) is available and may have a reduced incidence of adverse effects. The sustained-release formulation of clorazepate has some advantages in that, if a dose is missed, less profound fluctuations in blood plasma levels occur, which may be helpful to some people with epilepsy at risk of break-through seizures.

Adverse Effects

Adverse effects of clorazepate include tolerance, dependence, withdrawal reactions, cognitive impairment, confusion, anterograde amnesia, falls in the elderly, ataxia, hangover effects, and drowsiness. It is unclear whether cognitive deficits resulting from the long-term use of benzodiazepines return to normal or persist indefinitely after withdrawal from benzodiazepines. Benzodiazepines are also known to cause or worsen depression. Paradoxical effects including excitement and paradoxical worsening of seizures can sometimes result from the use of benzodiazepines. Children, the elderly, individuals with a history of alcohol use disorder or a history of aggressive behaviour and anger are at greater risk of developing paradoxical reactions to benzodiazepines.

In September 2020, the US Food and Drug Administration (FDA) required the boxed warning be updated for all benzodiazepine medicines to describe the risks of non-medical use, addiction, physical dependence, and withdrawal reactions consistently across all the medicines in the class.

Tolerance, Dependence and Withdrawal

Refer to Benzodiazepine Withdrawal Syndrome.

Delirium has been noted from discontinuation from clorazepate. A benzodiazepine dependence occurs in approximately one third of patients who take benzodiazepines for longer than 4 weeks, which is characterised by a withdrawal syndrome upon dose reduction. When used for seizure control, tolerance may manifest itself with an increased rate of seizures as well an increased risk of withdrawal seizures. In humans, tolerance to the anticonvulsant effects of clorazepate occurs frequently with regular use. Due to the development of tolerance, benzodiazepines are, in general, not considered appropriate for the long-term management of epilepsy; increasing the dose may result only in the developing of tolerance to the higher dose combined with worsened adverse effects. Cross-tolerance occurs between benzodiazepines, meaning that, if individuals are tolerant to one benzodiazepine, they will display a tolerance to equivalent doses of other benzodiazepines. Withdrawal symptoms from benzodiazepines include a worsening of pre-existing symptoms as well as the appearance of new symptoms that were not pre-existing. The withdrawal symptoms may range from mild anxiety and insomnia to severe withdrawal symptoms such as seizures and psychosis. Withdrawal symptoms can be difficult in some cases to differentiate between pre-existing symptoms and withdrawal symptoms. Use of high doses, long-term use and abrupt or over-rapid withdrawal increases increase the severity of withdrawal syndrome. However, tolerance to the active metabolite of clorazepate may occur more slowly than with other benzodiazepines. Regular use of benzodiazepines causes the development of dependence characterised by tolerance to the therapeutic effects of benzodiazepines and the development of the benzodiazepine withdrawal syndrome including symptoms such as anxiety, apprehension, tremor, insomnia, nausea, and vomiting upon cessation of benzodiazepine use. Withdrawal from benzodiazepines should be gradual as abrupt withdrawal from high doses of benzodiazepines may cause confusion, toxic psychosis, convulsions, or a condition resembling delirium tremens. Abrupt withdrawal from lower doses may cause depression, nervousness, rebound insomnia, irritability, sweating, and diarrhoea.

Interactions

All sedatives or hypnotics e.g. other benzodiazepines, barbiturates, antiepileptic drugs, alcohol, antihistamines, opioids, neuroleptics, sleep aids are likely to magnify the effects of clorazepate on the central nervous system. Drugs that may interact with clorazepate include, digoxin, disulfiram, fluoxetine, isoniazid, ketoconazole, levodopa, metoprolol, hormonal contraceptives, probenecid, propranolol, rifampin, theophylline, valproic acid. Selective serotonin reuptake inhibitors (SSRI), cimetidine, macrolide antibiotics and antimycotics inhibit the metabolism of benzodiazepines and may result in increased plasma levels with resultant enhancement of adverse effects. Phenytoin, phenobarbital, and carbamazepine have the opposite effect, with coadministration leading to increased metabolism and decreased therapeutic effects of clorazepate.

Contraindications and Special Caution

Benzodiazepines require special precaution if used in the elderly, children, alcohol- or drug-dependent individuals and individuals with comorbid psychiatric disorders.

Clorazepate if used late in pregnancy, the third trimester, causes a definite risk of severe benzodiazepine withdrawal syndrome in the neonate with symptoms including hypotonia, and reluctance to suck, to apnoeic spells, cyanosis, and impaired metabolic responses to cold stress. Floppy infant syndrome and sedation in the newborn may also occur. Symptoms of floppy infant syndrome and the neonatal benzodiazepine withdrawal syndrome have been reported to persist from hours to months after birth.

Special precaution is required when using clorazepate in the elderly because the elderly metabolise clorazepate more slowly, which may result in excessive drug accumulation. Additionally the elderly are more sensitive to the adverse effects of benzodiazepines compared to younger individuals even when blood plasma levels are the same. Use of benzodiazepines in the elderly is only recommended for 2 weeks and it is also recommended that half of the usual daily dose is prescribed.

Pharmacology

Clorazepate is a “classical” benzodiazepine. Other classical benzodiazepines include chlordiazepoxide, diazepam, clonazepam, oxazepam, lorazepam, nitrazepam, bromazepam and flurazepam. Clorazepate is a long-acting benzodiazepine drug. Clorazepate produces the active metabolite desmethyl-diazepam, which is a partial agonist of the GABAA receptor and has a half life of 20-179 hours; a small amount of desmethyldiazepam is further metabolised into oxazepam. Clorazepate exerts its pharmacological properties via increasing the opening frequency of the chloride ion channel of GABAA receptors. This effect of benzodiazepines requires the presence of the neurotransmitter GABA and results in enhanced inhibitory effects of the neurotransmitter GABA acting on GABAA receptors. Clorazepate, like other benzodiazepines, is widely distributed and is highly bound to plasma proteins; clorazepate also crosses readily over the placenta and into breast milk. Peak plasma levels of the active metabolite desmethyl-diazepam are seen between 30 minutes and 2 hours after oral administration of clorazepate. Clorazepate is completely metabolised to desmethyl-diazepam in the gastrointestinal tract and thus the pharmacological properties of clorazepate are largely due to desmethyldiazepam.

Chemistry

Clorazepate is used in the form of a dipotassium salt. It is unusual among benzodiazepines in that it is freely soluble in water.

Clorazepate can be synthesized starting from 2-amino-5-chlorobenzonitrile, which upon reaction with phenylmagnesium bromide is transformed into 2-amino-5-chlorbenzophenone imine. Reacting this with aminomalonic ester gives a heterocyclisation product, 7-chloro-1,3-dihydro-3-carbethoxy-5-phenyl-2H-benzodiazepin-2-one. Upon hydrolysis using an alcoholic solution of potassium hydroxide forms a dipotassium salt, chlorazepate.

Legal Status

In the United States, clorazepate is listed under Schedule IV of the Controlled Substances Act.

This page is based on the copyrighted Wikipedia article < https://en.wikipedia.org/wiki/Clorazepate >; 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 Clonazepam?

Published on by Andrew Marshall1 Comment

Introduction

Clonazepam, sold under the brand name Klonopin among others, is a medication used to prevent and treat seizures, panic disorder, anxiety, and the movement disorder known as akathisia. It is a tranquiliser of the benzodiazepine class. It is typically taken by mouth. Effects begin within one hour and last between six and twelve hours.

Common side effects include sleepiness, poor coordination, and agitation. Long-term use may result in tolerance, dependence, and withdrawal symptoms if stopped abruptly. Dependence occurs in one-third of people who take clonazepam for longer than four weeks. There is an increased risk of suicide, particularly in people who are already depressed. If used during pregnancy it may result in harm to the foetus. Clonazepam binds to GABAA receptors, thus increasing the effect of the chief inhibitory neurotransmitter γ-aminobutyric acid (GABA).

Clonazepam was patented in 1960 and went on sale in 1975 in the United States from Roche. It is available as a generic medication. In 2019, it was the 46th most commonly prescribed medication in the United States, with more than 15 million prescriptions. In many areas of the world it is commonly used as a recreational drug.

Medical Uses

Clonazepam is prescribed for short term management of epilepsy, anxiety, and panic disorder with or without agoraphobia.

Seizures

Clonazepam, like other benzodiazepines, while being a first-line treatment for acute seizures, is not suitable for the long-term treatment of seizures due to the development of tolerance to the anticonvulsant effects.

Clonazepam has been found effective in treating epilepsy in children, and the inhibition of seizure activity seemed to be achieved at low plasma levels of clonazepam. As a result, clonazepam is sometimes used for certain rare childhood epilepsies; however, it has been found to be ineffective in the control of infantile spasms. Clonazepam is mainly prescribed for the acute management of epilepsies. Clonazepam has been found to be effective in the acute control of non-convulsive status epilepticus; however, the benefits tended to be transient in many people, and the addition of phenytoin for lasting control was required in these patients.

It is also approved for treatment of typical and atypical absences (seizures), infantile myoclonic, myoclonic, and akinetic seizures. A subgroup of people with treatment resistant epilepsy may benefit from long-term use of clonazepam; the benzodiazepine clorazepate may be an alternative due to its slow onset of tolerance.

Anxiety Disorders

  • Panic disorder with or without agoraphobia.
  • Clonazepam has also been found effective in treating other anxiety disorders, such as social phobia, but this is an off-label use.

The effectiveness of clonazepam in the short-term treatment of panic disorder has been demonstrated in controlled clinical trials. Some long-term trials have suggested a benefit of clonazepam for up to three years without the development of tolerance but these trials were not placebo-controlled. Clonazepam is also effective in the management of acute mania.

Muscle Disorders

Restless legs syndrome can be treated using clonazepam as a third-line treatment option as the use of clonazepam is still investigational. Bruxism also responds to clonazepam in the short-term. Rapid eye movement sleep behaviour disorder responds well to low doses of clonazepam.

  • The treatment of acute and chronic akathisia induced by neuroleptics, also called antipsychotics.
  • Spasticity related to amyotrophic lateral sclerosis.
  • Alcohol withdrawal syndrome

Other

  • Benzodiazepines, such as clonazepam, are sometimes used for the treatment of mania or acute psychosis-induced aggression. In this context, benzodiazepines are given either alone, or in combination with other first-line drugs such as lithium, haloperidol, or risperidone. The effectiveness of taking benzodiazepines along with antipsychotic medication is unknown, and more research is needed to determine if benzodiazepines are more effective than antipsychotics when urgent sedation is required.
  • Hyperekplexia: A very rare neurologic disorder classically characterised by pronounced startle responses to tactile or acoustic stimuli and hypertonia.
  • Many forms of parasomnia and other sleep disorders are treated with clonazepam..
  • It is not effective for preventing migraines.

Contraindications

  • Coma.
  • Current alcohol use disorder.
  • Current substance use disorder.
  • Respiratory depression.

Adverse Effects

In September 2020, the US Food and Drug Administration (FDA) required the boxed warning be updated for all benzodiazepine medicines to describe the risks of abuse, misuse, addiction, physical dependence, and withdrawal reactions consistently across all the medicines in the class.

Common

  • Sedation.
  • Motor impairment.

Less Common

  • Confusion.
  • Irritability and aggression.
  • Psychomotor agitation.
  • Lack of motivation.
  • Loss of libido.
  • Impaired motor function.
  • Impaired coordination.
  • Impaired balance.
  • Dizziness.
  • Cognitive impairments.
  • Hallucinations.
  • Short-term memory loss.
  • Anterograde amnesia (common with higher doses).
  • Some users report hangover-like symptoms of drowsiness, headaches, sluggishness, and irritability upon waking up if the medication was taken before sleep.
    • This is likely the result of the medication’s long half-life, which continues to affect the user after waking up.
    • While benzodiazepines induce sleep, they tend to reduce the quality of sleep by suppressing or disrupting REM sleep.
    • After regular use, rebound insomnia may occur when discontinuing clonazepam.
  • Benzodiazepines may cause or worsen depression.

Occasional

  • Dysphoria.
  • Induction of seizures or increased frequency of seizures.
  • Personality changes.
  • Behavioural disturbances.
  • Ataxia.

Rare

  • Cognitive Euphoria.
  • Suicide through disinhibition.
  • Psychosis.
  • Incontinence.
  • Liver damage.
  • Paradoxical behavioural disinhibition (most frequently in children, the elderly, and in persons with developmental disabilities).
  • Rage.
  • Excitement.
  • Impulsivity.
  • The long-term effects of clonazepam can include depression, disinhibition, and sexual dysfunction.

Drowsiness

Clonazepam, like other benzodiazepines, may impair a person’s ability to drive or operate machinery. The central nervous system depressing effects of the drug can be intensified by alcohol consumption, and therefore alcohol should be avoided while taking this medication. Benzodiazepines have been shown to cause dependence. Patients dependent on clonazepam should be slowly titrated off under the supervision of a qualified healthcare professional to reduce the intensity of withdrawal or rebound symptoms.

Withdrawal-Related

  • Anxiety.
  • Irritability.
  • Insomnia.
  • Tremors.
  • Headaches.
  • Stomach pain.
  • Hallucinations.
  • Suicidal thoughts or urges.
  • Depression.
  • Fatigue.
  • Dizziness.
  • Sweating.
  • Confusion.
  • Potential to exacerbate existing panic disorder upon discontinuation.
  • Seizures similar to delirium tremens (with long-term use of excessive doses).

Benzodiazepines such as clonazepam can be very effective in controlling status epilepticus, but, when used for longer periods of time, some potentially serious side-effects may develop, such as interference with cognitive functions and behaviour. Many individuals treated on a long-term basis develop a dependence. Physiological dependence was demonstrated by flumazenil-precipitated withdrawal. Use of alcohol or other central nervous system (CNS)-depressants while taking clonazepam greatly intensifies the effects (and side effects) of the drug.

A recurrence of symptoms of the underlying disease should be separated from withdrawal symptoms.

Tolerance and Withdrawal

Refer to Benzodiazepine Withdrawal Syndrome.

Like all benzodiazepines, clonazepam is a GABA-positive allosteric modulator. One-third of individuals treated with benzodiazepines for longer than four weeks develop a dependence on the drug and experience a withdrawal syndrome upon dose reduction. High dosage and long-term use increase the risk and severity of dependence and withdrawal symptoms. Withdrawal seizures and psychosis can occur in severe cases of withdrawal, and anxiety and insomnia can occur in less severe cases of withdrawal. A gradual reduction in dosage reduces the severity of the benzodiazepine withdrawal syndrome. Due to the risks of tolerance and withdrawal seizures, clonazepam is generally not recommended for the long-term management of epilepsies. Increasing the dose can overcome the effects of tolerance, but tolerance to the higher dose may occur and adverse effects may intensify. The mechanism of tolerance includes receptor desensitisation, down regulation, receptor decoupling, and alterations in subunit composition and in gene transcription coding.

Tolerance to the anticonvulsant effects of clonazepam occurs in both animals and humans. In humans, tolerance to the anticonvulsant effects of clonazepam occurs frequently. Chronic use of benzodiazepines can lead to the development of tolerance with a decrease of benzodiazepine binding sites. The degree of tolerance is more pronounced with clonazepam than with chlordiazepoxide. In general, short-term therapy is more effective than long-term therapy with clonazepam for the treatment of epilepsy. Many studies have found that tolerance develops to the anticonvulsant properties of clonazepam with chronic use, which limits its long-term effectiveness as an anticonvulsant.

Abrupt or over-rapid withdrawal from clonazepam may result in the development of the benzodiazepine withdrawal syndrome, causing psychosis characterised by dysphoric manifestations, irritability, aggressiveness, anxiety, and hallucinations. Sudden withdrawal may also induce the potentially life-threatening condition, status epilepticus. Anti-epileptic drugs, benzodiazepines such as clonazepam in particular, should be reduced in dose slowly and gradually when discontinuing the drug to mitigate withdrawal effects. Carbamazepine has been tested in the treatment of clonazepam withdrawal but was found to be ineffective in preventing clonazepam withdrawal-induced status epilepticus from occurring.

Overdose

Refer to Benzodiazepine Overdose.

Excess doses may result in:

  • Difficulty staying awake.
  • Mental confusion.
  • Impaired motor functions.
  • Impaired reflexes.
  • Impaired coordination.
  • Impaired balance.
  • Dizziness.
  • Respiratory depression.
  • Low blood pressure.
  • Coma.

Coma can be cyclic, with the individual alternating from a comatose state to a hyper-alert state of consciousness, which occurred in a four-year-old boy who overdosed on clonazepam. The combination of clonazepam and certain barbiturates (for example, amobarbital), at prescribed doses has resulted in a synergistic potentiation of the effects of each drug, leading to serious respiratory depression.

Overdose symptoms may include extreme drowsiness, confusion, muscle weakness, and fainting.

Detection in Biological Fluids

Clonazepam and 7-aminoclonazepam may be quantified in plasma, serum, or whole blood in order to monitor compliance in those receiving the drug therapeutically. Results from such tests can be used to confirm the diagnosis in potential poisoning victims or to assist in the forensic investigation in a case of fatal overdosage. Both the parent drug and 7-aminoclonazepam are unstable in biofluids, and therefore specimens should be preserved with sodium fluoride, stored at the lowest possible temperature and analysed quickly to minimise losses.

Special Precautions

The elderly metabolise benzodiazepines more slowly than younger people and are also more sensitive to the effects of benzodiazepines, even at similar blood plasma levels. Doses for the elderly are recommended to be about half of that given to younger adults and are to be administered for no longer than two weeks. Long-acting benzodiazepines such as clonazepam are not generally recommended for the elderly due to the risk of drug accumulation.

The elderly are especially susceptible to increased risk of harm from motor impairments and drug accumulation side effects. Benzodiazepines also require special precaution if used by individuals that may be pregnant, alcohol- or drug-dependent, or may have comorbid psychiatric disorders. Clonazepam is generally not recommended for use in elderly people for insomnia due to its high potency relative to other benzodiazepines.

Clonazepam is not recommended for use in those under 18. Use in very young children may be especially hazardous. Of anticonvulsant drugs, behavioural disturbances occur most frequently with clonazepam and phenobarbital.

Doses higher than 0.5-1 mg per day are associated with significant sedation.

Clonazepam may aggravate hepatic porphyria.

Clonazepam is not recommended for patients with chronic schizophrenia. A 1982 double-blinded, placebo-controlled study found clonazepam increases violent behaviour in individuals with chronic schizophrenia.

Clonazepam has similar effectiveness to other benzodiazepines at often a lower dose.

Interactions

Clonazepam decreases the levels of carbamazepine, and, likewise, clonazepam’s level is reduced by carbamazepine. Azole antifungals, such as ketoconazole, may inhibit the metabolism of clonazepam. Clonazepam may affect levels of phenytoin (diphenylhydantoin). In turn, Phenytoin may lower clonazepam plasma levels by increasing the speed of clonazepam clearance by approximately 50% and decreasing its half-life by 31%. Clonazepam increases the levels of primidone and phenobarbital.

Combined use of clonazepam with certain antidepressants, anticonvulsants (such as phenobarbital, phenytoin, and carbamazepine), sedative antihistamines, opiates, and antipsychotics, nonbenzodiazepines (such as zolpidem), and alcohol may result in enhanced sedative effects.

Pregnancy

There is some medical evidence of various malformations (for example, cardiac or facial deformations when used in early pregnancy); however, the data is not conclusive. The data are also inconclusive on whether benzodiazepines such as clonazepam cause developmental deficits or decreases in IQ in the developing foetus when taken by the mother during pregnancy. Clonazepam, when used late in pregnancy, may result in the development of a severe benzodiazepine withdrawal syndrome in the neonate. Withdrawal symptoms from benzodiazepines in the neonate may include hypotonia, apnoeic spells, cyanosis, and impaired metabolic responses to cold stress.

The safety profile of clonazepam during pregnancy is less clear than that of other benzodiazepines, and if benzodiazepines are indicated during pregnancy, chlordiazepoxide and diazepam may be a safer choice. The use of clonazepam during pregnancy should only occur if the clinical benefits are believed to outweigh the clinical risks to the foetus. Caution is also required if clonazepam is used during breastfeeding. Possible adverse effects of use of benzodiazepines such as clonazepam during pregnancy include: miscarriage, malformation, intrauterine growth retardation, functional deficits, carcinogenesis, and mutagenesis. Neonatal withdrawal syndrome associated with benzodiazepines include hypertonia, hyperreflexia, restlessness, irritability, abnormal sleep patterns, inconsolable crying, tremors, or jerking of the extremities, bradycardia, cyanosis, suckling difficulties, apnoea, risk of aspiration of feeds, diarrhoea and vomiting, and growth retardation. This syndrome can develop between three days to three weeks after birth and can have a duration of up to several months. The pathway by which clonazepam is metabolised is usually impaired in newborns. If clonazepam is used during pregnancy or breastfeeding, it is recommended that serum levels of clonazepam are monitored and that signs of central nervous system depression and apnoea are also checked for. In many cases, non-pharmacological treatments, such as relaxation therapy, psychotherapy, and avoidance of caffeine, can be an effective and safer alternative to the use of benzodiazepines for anxiety in pregnant women.

Pharmacology

Mechanism of Action

Clonazepam enhances the activity of the inhibitory neurotransmitter gamma-aminobutyric acid (GABA) in the central nervous system to give its anticonvulsant, skeletal muscle relaxant, and anxiolytic effects. It acts by binding to the benzodiazepine site of the GABA receptors, which enhances the electric effect of GABA binding on neurons, resulting in an increased influx of chloride ions into the neurons. This further results in an inhibition of synaptic transmission across the central nervous system.

Benzodiazepines do not have any effect on the levels of GABA in the brain. Clonazepam has no effect on GABA levels and has no effect on gamma-aminobutyric acid transaminase. Clonazepam does, however, affect glutamate decarboxylase activity. It differs from other anticonvulsant drugs it was compared to in a study.

Clonazepam’s primary mechanism of action is the modulation of GABA function in the brain, by the benzodiazepine receptor, located on GABAA receptors, which, in turn, leads to enhanced GABAergic inhibition of neuronal firing. Benzodiazepines do not replace GABA, but instead enhance the effect of GABA at the GABAA receptor by increasing the opening frequency of chloride ion channels, which leads to an increase in GABA’s inhibitory effects and resultant central nervous system depression. In addition, clonazepam decreases the utilisation of 5-HT (serotonin) by neurons and has been shown to bind tightly to central-type benzodiazepine receptors. Because clonazepam is effective in low milligram doses (0.5 mg clonazepam = 10 mg diazepam), it is said to be among the class of “highly potent” benzodiazepines. The anticonvulsant properties of benzodiazepines are due to the enhancement of synaptic GABA responses, and the inhibition of sustained, high-frequency repetitive firing.

Benzodiazepines, including clonazepam, bind to mouse glial cell membranes with high affinity. Clonazepam decreases release of acetylcholine in the feline brain and decreases prolactin release in rats. Benzodiazepines inhibit cold-induced thyroid-stimulating hormone (also known as TSH or thyrotropin) release. Benzodiazepines act via micromolar benzodiazepine binding sites as Ca2+ channel blockers and significantly inhibit depolarisation-sensitive calcium uptake in experimentation on rat brain cell components. This has been conjectured as a mechanism for high-dose effects on seizures in the study.

Clonazepam is a 2′-chlorinated derivative of nitrazepam, which increases its potency due to electron-attracting effect of the halogen in the ortho-position.

Pharmacokinetics

Clonazepam is lipid-soluble, rapidly crosses the blood-brain barrier, and penetrates the placenta. It is extensively metabolised into pharmacologically inactive metabolites, with only 2% of the unchanged drug excreted in the urine. Clonazepam is metabolised extensively via nitroreduction by cytochrome P450 enzymes, including CYP3A4. Erythromycin, clarithromycin, ritonavir, itraconazole, ketoconazole, nefazodone, cimetidine, and grapefruit juice are inhibitors of CYP3A4 and can affect the metabolism of benzodiazepines. It has an elimination half-life of 19-60 hours. Peak blood concentrations of 6.5-13.5 ng/mL were usually reached within 1-2 hours following a single 2 mg oral dose of micronized clonazepam in healthy adults. In some individuals, however, peak blood concentrations were reached at 4-8 hours.

Clonazepam passes rapidly into the central nervous system, with levels in the brain corresponding with levels of unbound clonazepam in the blood serum. Clonazepam plasma levels are very unreliable amongst patients. Plasma levels of clonazepam can vary as much as tenfold between different patients.

Clonazepam has plasma protein binding of 85%. Clonazepam passes through the blood-brain barrier easily, with blood and brain levels corresponding equally with each other. The metabolites of clonazepam include 7-aminoclonazepam, 7-acetaminoclonazepam and 3-hydroxy clonazepam. These metabolites are excreted by the kidney.

It is effective for 6-8 hours in children, and 6-12 in adults.

Society and Culture

Recreational Use

Refer to Benzodiazepine Misuse.

A 2006 US government study of hospital emergency department (ED) visits found that sedative-hypnotics were the most frequently implicated pharmaceutical drug in visits, with benzodiazepines accounting for the majority of these. Clonazepam was the second most frequently implicated benzodiazepine in ED visits. Alcohol alone was responsible for over twice as many ED visits as clonazepam in the same study. The study examined the number of times the non-medical use of certain drugs was implicated in an ED visit. The criteria for non-medical use in this study were purposefully broad, and include, for example, drug abuse, accidental or intentional overdose, or adverse reactions resulting from legitimate use of the medication.

Formulations

Clonazepam was approved in the United States as a generic drug in 1997 and is now manufactured and marketed by several companies.

Clonazepam is available as tablets and orally disintegrating tablets (wafers) an oral solution (drops), and as a solution for injection or intravenous infusion.

Brand Names

It is marketed under the trade name Rivotril by Roche in Argentina, Australia, Austria, Bangladesh, Belgium, Brazil, Bulgaria, Canada, Colombia, Costa Rica, Croatia, the Czech Republic, Denmark, Estonia,[136] Germany, Hungary, Iceland, Ireland, Italy, China, Mexico, the Netherlands, Norway, Portugal, Peru, Pakistan, Romania, Serbia, South Africa, South Korea, Spain, Turkey, and the United States; Emcloz, Linotril and Clonotril in India and other parts of Europe; under the name Riklona in Indonesia and Malaysia; and under the trade name Klonopin by Roche in the United States. Other names, such as Clonoten, Ravotril, Rivotril, Iktorivil, Clonex (Israel), Paxam, Petril, Naze, Zilepam and Kriadex, are known throughout the world.

This page is based on the copyrighted Wikipedia article < https://en.wikipedia.org/wiki/Clonazepam >; 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 Bromazolam?

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Introduction

Bromazolam (XLI-268) is a triazolobenzodiazepine (TBZD) which was first synthesised in 1976, but was never marketed. It has subsequently been sold as a designer drug, first being definitively identified by the EMCDDA in Sweden in 2016.

Outline

It is the bromo instead of chloro analogue of alprazolam and has similar sedative and anxiolytic effects to it and other benzodiazepines. Bromazolam is a non subtype selective agonist at the benzodiazepine site of GABAA receptors, with a binding affinity of 2.81nM at the α1 subtype, 0.69nM at α2 and 0.62nM at α5.

This page is based on the copyrighted Wikipedia article < https://en.wikipedia.org/wiki/Bromazolam >; 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 Bromazepam?

Published on by Andrew Marshall1 Comment

Introduction

Bromazepam, sold under many brand names, is a benzodiazepine. It is mainly an anti-anxiety agent with similar side effects to diazepam (Valium). In addition to being used to treat anxiety or panic states, bromazepam may be used as a premedicant prior to minor surgery. Bromazepam typically comes in doses of 3 mg and 6 mg tablets.

It was patented in 1961 by Roche and approved for medical use in 1974.

Medical Uses

Treatment of severe anxiety. Despite certain side effects and the emergence of alternative products (e.g. pregabalin), benzodiazepine medication remains an effective way of reducing problematic symptoms, and is typically deemed effective by patients and medical professionals. Similarly to other intermediate-acting depressants, it may be used as hypnotic medication or in order to mitigate withdrawal effects of alcohol consumption.

Pharmacology

Bromazepam is a “classical” benzodiazepine; other classical benzodiazepines include: diazepam, clonazepam, oxazepam, lorazepam, nitrazepam, flurazepam, and clorazepate. Its molecular structure is composed of a diazepine connected to a benzene ring and a pyridine ring, the benzene ring having a single nitrogen atom that replaces one of the carbon atoms in the ring structure. It is a 1,4-benzodiazepine, which means that the nitrogens on the seven-sided diazepine ring are in the 1 and 4 positions.

Bromazepam binds to the GABA receptor GABAA, causing a conformational change and increasing the inhibitory effects of GABA. It acts as a positive modulator, increasing the receptors’ response when activated by GABA itself or an agonist (such as alcohol). As opposed to barbital, BZDs are not GABA-receptor activators and rely on increasing the neurotransmitter’s natural activity. Bromazepam is an intermediate-acting benzodiazepine, is moderately lipophilic compared to other substances of its class and metabolised hepatically via oxidative pathways. It does not possess any antidepressant or antipsychotic qualities.

After night time administration of bromazepam a highly significant reduction of gastric acid secretion occurs during sleep followed by a highly significant rebound in gastric acid production the following day.

Bromazepam alters the electrical status of the brain causing an increase in beta activity and a decrease in alpha activity in EEG recordings

Pharmacokinetics

Bromazepam is reported to be metabolised by a hepatic enzyme belonging to the Cytochrome P450 family of enzymes. In 2003, a team led by Oda Manami at Oita Medical University reported that CYP3A4, a member of the Cytochrome P450 family, was not the responsible enzyme since itraconazole, a known inhibitor of CYP3A4, did not affect its metabolism. In 1995, J. van Harten at the Solvay Pharmaceutical Department of Clinical Pharmacology in Weesp reported that fluvoxamine, which is a potent inhibitor of CYP1A2, a less potent CYP3A4 inhibitor, and a negligible inhibitor of CYP2D6, does inhibit its metabolism.

The major metabolite of bromazepam is hydroxybromazepam, which is an active agent too and has a half-life approximately equal to that of bromazepam.

Side-Effects

Bromazepam is similar in side effects to other benzodiazepines. The most common side effects reported are drowsiness, sedation, ataxia, memory impairment, and dizziness. Impairments to memory functions are common with bromazepam and include a reduced working memory and reduced ability to process environmental information. A 1975 experiment on healthy, male college students exploring the effects of four different drugs on learning capacity observed that taking bromazepam alone at 6 mg 3 times daily for 2 weeks impaired learning capacities significantly. In combination with alcohol, impairments in learning capacity became even more pronounced. Various studies report impaired memory, visual information processing and sensory data and impaired psychomotor performance; deterioration of cognition including attention capacity and impaired co-ordinative skills; impaired reactive and attention performance, which can impair driving skills; drowsiness and decrease in libido. Unsteadiness after taking bromazepam is, however, less pronounced than other benzodiazepines such as lorazepam.

On occasion, benzodiazepines can induce extreme alterations in memory such as anterograde amnesia and amnesic automatism, which may have medico-legal consequences. Such reactions occur usually only at the higher dose end of the prescribing spectrum.

Very rarely, dystonia can develop.

Up to 30% treated on a long-term basis develop a form of dependence, i.e. these patients cannot stop the medication without experiencing physical and/or psychological benzodiazepine withdrawal symptoms.

Leukopenia and liver-damage of the cholestatic type with or without jaundice (icterus) have additionally been seen; the original manufacturer Roche recommends regular laboratory examinations to be performed routinely.

Ambulatory patients should be warned that bromazepam may impair the ability to drive vehicles and to operate machinery. The impairment is worsened by consumption of alcohol, because both act as central nervous system depressants. During the course of therapy, tolerance to the sedative effect usually develops.

Frequency and Seriousness of Adverse Effects

As with all medication, the frequency and seriousness of side-effects varies greatly depending on quantities consumed. In a study about bromazepam’s negative effects on psychomotor skills and driving ability, it was noted that 3 mg doses caused minimal impairment. It also appeared that impairment may be tied to methods of testing more so than on the product’s intrinsic activity.

Moreover, side-effects other than drowsiness, dizziness and ataxia seem to be rare and not experienced by more than a few percent of users. The use of other, comparable medication seems to display an identically moderate side-effect profile.

Tolerance, Dependence and Withdrawal

Prolonged use of bromazepam can cause tolerance and may lead to both physical and psychological dependence on the drug, and as a result, it is a medication which is controlled by international law. It is nonetheless important to note that dependence, long-term use and misuse occur in a minority of cases and are not representative of most patients’ experience with this type of medication.

It shares with other benzodiazepines the risk of abuse, misuse, psychological dependence or physical dependence. A withdrawal study demonstrated both psychological dependence and physical dependence on bromazepam including marked rebound anxiety after 4 weeks chronic use. Those whose dose was gradually reduced experienced no withdrawal.

Patients treated with bromazepam for generalised anxiety disorder were found to experience withdrawal symptoms such as a worsening of anxiety, as well as the development of physical withdrawal symptoms when abruptly withdrawn bromazepam. Abrupt or over rapid withdrawal from bromazepam after chronic use even at therapeutic prescribed doses can lead to a severe withdrawal syndrome including status epilepticus and a condition resembling delirium tremens.

Animal studies have shown that chronic administration of diazepam (or bromazepam) causes a decrease in spontaneous locomotor activity, decreased turnover of noradrenaline and dopamine and serotonin, increased activity of tyrosine hydroxylase and increased levels of the catecholamines. During withdrawal of bromazepam or diazepam a fall in tryptophan, serotonin levels occurs as part of the benzodiazepine withdrawal syndrome. Changes in the levels of these chemicals in the brain can cause headaches, anxiety, tension, depression, insomnia, restlessness, confusion, irritability, sweating, dysphoria, dizziness, derealisation, depersonalisation, numbness/tingling of extremities, hypersensitivity to light, sound, and smell, perceptual distortions, nausea, vomiting, diarrhoea, appetite loss, hallucinations, delirium, seizures, tremor, stomach cramps, myalgia, agitation, palpitations, tachycardia, panic attacks, short-term memory loss, and hyperthermia.

Overdose

Refer to Benzodiazepine Overdose.

Bromazepam is commonly involved in drug overdoses. A severe bromazepam benzodiazepine overdose may result in an alpha pattern coma type. The toxicity of bromazepam in overdosage increases when combined with other CNS depressant drugs such as alcohol or sedative hypnotic drugs. Similarly to other benzodiazepines however, being a positive modulator of certain neuroreceptors and not an agonist, the product has reduced overdose potential compared to older products of the barbiturate class. Its consumption alone is very seldom fatal in healthy adults.

Bromazepam was in 2005 the most common benzodiazepine involved in intentional overdoses in France. Bromazepam has also been responsible for accidental poisonings in companion animals. A review of benzodiazepine poisonings in cats and dogs from 1991-1994 found bromazepam to be responsible for significantly more poisonings than any other benzodiazepine.

Contraindications

Benzodiazepines require special precaution if used in elderly, pregnant, child, alcohol- or drug-dependent individuals and individuals with comorbid psychiatric disorders.

Special Populations

  • Globally, bromazepam is contraindicated and should be used with caution in women who are pregnant, the elderly, patients with a history of alcohol or other substance abuse disorders and children.
  • In 1987, a team of scientists led by Ochs reported that the elimination half-life, peak serum concentration, and serum free fraction are significantly elevated and the oral clearance and volume of distribution significantly lowered in elderly subjects. The clinical consequence is that the elderly should be treated with lower doses than younger patients.
  • Bromazepam may affect driving and ability to operate machinery.
  • Bromazepam is pregnancy category D, a classification that means that bromazepam has been shown to cause harm to the unborn child. The Hoffman LaRoche product information leaflet warns against breast feeding while taking bromazepam. There has been at least one report of sudden infant death syndrome linked to breast feeding while consuming bromazepam.

Interactions

Cimetidine, fluvoxamine and propranolol causes a marked increase in the elimination half-life of bromazepam leading to increased accumulation of bromazepam.

Society and Culture

Drug Misuse

Refer to Benzodiazepine Drug Misuse.

Bromazepam has a similar misuse risk as other benzodiazepines such as diazepam. In France car accidents involving psychotropic drugs in combination with alcohol (itself a major contributor) found benzodiazepines, mainly diazepam, nordiazepam, and bromazepam, to be the most common drug present in the blood stream, almost twice that of the next-most-common drug cannabis. Bromazepam has also been used in serious criminal offences including robbery, homicide, and sexual assault.

Brand Names

It is marketed under several brand names, including, Brozam, Lectopam, Lexomil, Lexotan, Lexilium, Lexaurin, Brazepam, Rekotnil, Bromaze, Somalium, Lexatin, Calmepam, Zepam and Lexotanil.

Legal Status

Bromazepam is a Schedule IV drug under the Convention on Psychotropic Substances.

This page is based on the copyrighted Wikipedia article < https://en.wikipedia.org/wiki/Bromazepam >; 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.

Clinical Institute Withdrawal Assessment for Alcohol?

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Introduction

The Clinical Institute Withdrawal Assessment for Alcohol, commonly abbreviated as CIWA or CIWA-Ar (revised version), is a 10-item scale used in the assessment and management of alcohol withdrawal.

Each item on the scale is scored independently, and the summation of the scores yields an aggregate value that correlates to the severity of alcohol withdrawal, with ranges of scores designed to prompt specific management decisions such as the administration of benzodiazepines. The maximum score is 67; Mild alcohol withdrawal is defined with a score less than or equal to 10, moderate with scores 11 to 15, and severe with any score equal to or greater than 16.

CIWA-Ar

The CIWA-Ar is actually a shortened, improved version of the CIWA, geared towards objectifying alcohol withdrawal symptom severity. It retains validity, usefulness and reliability between rater’s. This revised version is the most commonly used scale in alcohol withdrawal, and was developed at the Addiction Research Foundation (now Centre for Addiction and Mental Health).

Scale

The ten items evaluated on the scale are common symptoms and signs of alcohol withdrawal, and are as follows:

  • Nausea and vomiting.
  • Tremor.
  • Paroxysmal sweats.
  • Anxiety.
  • Agitation.
  • Tactile disturbances.
  • Auditory disturbances.
  • Visual disturbances.
  • Headache.
  • Orientation and clouded sensorium.

Scoring

All items are scored from 0-7, with the exception of the orientation category, scored from 0-4. The CIWA scale is validated and has high inter-rater reliability. A randomised, double blind trial published in JAMA in 1994 showed that management for alcohol withdrawal that was guided by the CIWA scale resulted in decreased treatment duration and total use of benzodiazepines. The goal of the CIWA scale is to provide an efficient and objective means of assessing alcohol withdrawal. Studies have shown that use of the scale in management of alcohol withdrawal leads to decreased frequency of over-sedation with benzodiazepines in patients with milder alcohol withdrawal than would otherwise be detected without use of the scale, and decreased frequency of under-treatment in patients with greater severity of withdrawal than would otherwise be determined without the scale.

This page is based on the copyrighted Wikipedia article <https://en.wikipedia.org/wiki/Clinical_Institute_Withdrawal_Assessment_for_Alcohol >; 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 Climazolam?

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Introduction

Climazolam was introduced under licence as a veterinary medicine by the Swiss Pharmaceutical company Gräub under the tradename Climasol.

Background

Climazolam is a benzodiazepine, specifically an imidazobenzodiazepine derivative developed by Hoffman-LaRoche.

It is similar in structure to midazolam and diclazepam and is used in veterinary medicine for anaesthetising animals.

What is Midazolam?

Published on by Andrew Marshall1 Comment

Introduction

Midazolam, sold under the brand name Versed, among others, is a benzodiazepine medication used for anaesthesia, procedural sedation, trouble sleeping, and severe agitation.

It works by inducing sleepiness, decreasing anxiety, and causing a loss of ability to create new memories. It is important to note that this drug does not cause an individual to become unconscious, merely be sedated. It is also useful for the treatment of seizures. Midazolam can be given by mouth, intravenously, by injection into a muscle, by spraying into the nose, or through the cheek. When given intravenously, it typically begins working within five minutes; when injected into a muscle, it can take fifteen minutes to begin working. Effects last between one and six hours.

Side effects can include a decrease in efforts to breathe, low blood pressure, and sleepiness. Tolerance to its effects and withdrawal syndrome may occur following long-term use. Paradoxical effects, such as increased activity, can occur especially in children and older people. There is evidence of risk when used during pregnancy but no evidence of harm with a single dose during breastfeeding. It belongs to the benzodiazepine class of drugs and works by increasing the activity of the GABA neurotransmitter in the brain.

Midazolam was patented in 1974 and came into medical use in 1982. It is on the World Health Organisation’s List of Essential Medicines. Midazolam is available as a generic medication. In many countries, it is a controlled substance.

Brief History

Midazolam is among about 35 benzodiazepines currently used medically, and was synthesized in 1975 by Walser and Fryer at Hoffmann-LaRoche, Inc in the United States. Owing to its water solubility, it was found to be less likely to cause thrombophlebitis than similar drugs. The anticonvulsant properties of midazolam were studied in the late 1970s, but not until the 1990s did it emerge as an effective treatment for convulsive status epilepticus. As of 2010, it is the most commonly used benzodiazepine in anaesthetic medicine. In acute medicine, midazolam has become more popular than other benzodiazepines, such as lorazepam and diazepam, because it is shorter lasting, is more potent, and causes less pain at the injection site. Midazolam is also becoming increasingly popular in veterinary medicine due to its water solubility. In 2018 it was revealed the CIA considered using Midazolam as a “truth serum” on terrorist suspects in project “Medication”.

Medical Uses

Seizures

Midazolam is sometimes used for the acute management of seizures. Long-term use for the management of epilepsy is not recommended due to the significant risk of tolerance (which renders midazolam and other benzodiazepines ineffective) and the significant side effect of sedation. A benefit of midazolam is that in children it can be given in the cheek or in the nose for acute seizures, including status epilepticus. Midazolam is effective for status epilepticus that has not improved following other treatments or when intravenous access cannot be obtained, and has advantages of being water-soluble, having a rapid onset of action and not causing metabolic acidosis from the propylene glycol vehicle (which is not required due to its solubility in water), which occurs with other benzodiazepines.

Drawbacks include a high degree of breakthrough seizures – due to the short half-life of midazolam – in over 50% of people treated, as well as treatment failure in 14-18% of people with refractory status epilepticus. Tolerance develops rapidly to the anticonvulsant effect, and the dose may need to be increased by several times to maintain anticonvulsant therapeutic effects. With prolonged use, tolerance and tachyphylaxis can occur and the elimination half-life may increase, up to days. There is evidence buccal and intranasal midazolam is easier to administer and more effective than rectally administered diazepam in the emergency control of seizures.

Procedural Sedation

Intravenous midazolam is indicated for procedural sedation (often in combination with an opioid, such as fentanyl), for preoperative sedation, for the induction of general anaesthesia, and for sedation of people who are ventilated in critical care units. Midazolam is superior to diazepam in impairing memory of endoscopy procedures, but propofol has a quicker recovery time and a better memory-impairing effect. It is the most popular benzodiazepine in the intensive care unit (ICU) because of its short elimination half-life, combined with its water solubility and its suitability for continuous infusion. However, for long-term sedation, lorazepam is preferred due to its long duration of action, and propofol has advantages over midazolam when used in the ICU for sedation, such as shorter weaning time and earlier tracheal extubation.

Midazolam is sometimes used in neonatal intensive care units. When used, additional caution is required in newborns; midazolam should not be used for longer than 72 hours due to risks of tachyphylaxis, and the possibility of development of a benzodiazepine withdrawal syndrome, as well as neurological complications. Bolus injections should be avoided due to the increased risk of cardiovascular depression, as well as neurological complications. Midazolam is also sometimes used in newborns who are receiving mechanical ventilation, although morphine is preferred, owing to its better safety profile for this indication.

Sedation using midazolam can be used to relieve anxiety and manage behaviour in children undergoing dental treatment.

Agitation

Midazolam, in combination with an antipsychotic drug, is indicated for the acute management of schizophrenia when it is associated with aggressive or out-of-control behaviour.

End of Life Care

In the final stages of end-of-life care, midazolam is routinely used at low doses via subcutaneous injection to help with agitation, myoclonus, restlessness or anxiety in the last hours or days of life. At higher doses during the last weeks of life, midazolam is considered a first line agent in palliative continuous deep sedation therapy when it is necessary to alleviate intolerable suffering not responsive to other treatments, but the need for this is rare.

Administration

Routes of administration of midazolam can be oral, intranasal, buccal, intravenous, and intramuscular.

  • Dosing:
    • Perioperative use: 0.15 to 0.40 mg/kg IV.
    • Premedication: 0.07 to 0.10 mg/kg IM.
    • Intravenous sedation: 0.05 to 0.15 mg/kg IV.

Contraindications

Benzodiazepines require special precaution if used in the elderly, during pregnancy, in children, in alcohol- or other drug-dependent individuals or those with comorbid psychiatric disorders. Additional caution is required in critically ill patients, as accumulation of midazolam and its active metabolites may occur. Kidney or liver impairments may slow down the elimination of midazolam leading to prolonged and enhanced effects. Contraindications include hypersensitivity, acute narrow-angle glaucoma, shock, hypotension, or head injury. Most are relative contraindications.

Side Effects

Refer to Long-Term Effects of Benzodiazepines.

Side effects of midazolam in the elderly are listed above. People experiencing amnesia as a side effect of midazolam are generally unaware their memory is impaired, unless they had previously known it as a side effect.

Long-term use of benzodiazepines has been associated with long-lasting deficits of memory, and show only partial recovery six months after stopping benzodiazepines. It is unclear whether full recovery occurs after longer periods of abstinence. Benzodiazepines can cause or worsen depression. Paradoxical excitement occasionally occurs with benzodiazepines, including a worsening of seizures. Children and elderly individuals or those with a history of excessive alcohol use and individuals with a history of aggressive behaviour or anger are at increased risk of paradoxical effects. Paradoxical reactions are particularly associated with intravenous administration. After night-time administration of midazolam, residual ‘hangover’ effects, such as sleepiness and impaired psychomotor and cognitive functions, may persist into the next day. This may impair the ability of users to drive safely and may increase the risk of falls and hip fractures. Sedation, respiratory depression and hypotension due to a reduction in systematic vascular resistance, and an increase in heart rate can occur. If intravenous midazolam is given too quickly, hypotension may occur. A “midazolam infusion syndrome” may result from high doses, and is characterised by delayed arousal hours to days after discontinuation of midazolam, and may lead to an increase in the length of ventilatory support needed.

In susceptible individuals, midazolam has been known to cause a paradoxical reaction, a well-documented complication with benzodiazepines. When this occurs, the individual may experience anxiety, involuntary movements, aggressive or violent behaviour, uncontrollable crying or verbalization, and other similar effects. This seems to be related to the altered state of consciousness or disinhibition produced by the drug. Paradoxical behaviour is often not recalled by the patient due to the amnesia-producing properties of the drug. In extreme situations, flumazenil can be administered to inhibit or reverse the effects of midazolam. Antipsychotic medications, such as haloperidol, have also been used for this purpose.

Midazolam is known to cause respiratory depression. In healthy humans, 0.15 mg/kg of midazolam may cause respiratory depression, which is postulated to be a central nervous system (CNS) effect. When midazolam is administered in combination with fentanyl, the incidence of hypoxemia or apnoea becomes more likely.

Although the incidence of respiratory depression/arrest is low (0.1-0.5%) when midazolam is administered alone at normal doses, the concomitant use with CNS acting drugs, mainly analgesic opiates, may increase the possibility of hypotension, respiratory depression, respiratory arrest, and death, even at therapeutic doses. Potential drug interactions involving at least one CNS depressant were observed for 84% of midazolam users who were subsequently required to receive the benzodiazepine antagonist flumazenil. Therefore, efforts directed toward monitoring drug interactions and preventing injuries from midazolam administration are expected to have a substantial impact on the safe use of this drug.

Pregnancy and Breastfeeding

Midazolam, when taken during the third trimester of pregnancy, may cause risk to the neonate, including benzodiazepine withdrawal syndrome, with possible symptoms including hypotonia, apnoeic spells, cyanosis, and impaired metabolic responses to cold stress. Symptoms of hypotonia and the neonatal benzodiazepine withdrawal syndrome have been reported to persist from hours to months after birth. Other neonatal withdrawal symptoms include hyperexcitability, tremor, and gastrointestinal upset (diarrhoea or vomiting). Breastfeeding by mothers using midazolam is not recommended.

Elderly

Additional caution is required in the elderly, as they are more sensitive to the pharmacological effects of benzodiazepines, metabolise them more slowly, and are more prone to adverse effects, including drowsiness, amnesia (especially anterograde amnesia), ataxia, hangover effects, confusion, and falls.

Tolerance, Dependence, and Withdrawal

A benzodiazepine dependence occurs in about one-third of individuals who are treated with benzodiazepines for longer than 4 weeks, which typically results in tolerance and benzodiazepine withdrawal syndrome when the dose is reduced too rapidly. Midazolam infusions may induce tolerance and a withdrawal syndrome in a matter of days. The risk factors for dependence include dependent personality, use of a benzodiazepine that is short-acting, high potency and long-term use of benzodiazepines. Withdrawal symptoms from midazolam can range from insomnia and anxiety to seizures and psychosis. Withdrawal symptoms can sometimes resemble a person’s underlying condition. Gradual reduction of midazolam after regular use can minimise withdrawal and rebound effects. Tolerance and the resultant withdrawal syndrome may be due to receptor down-regulation and GABAA receptor alterations in gene expression, which causes long-term changes in the function of the GABAergic neuronal system.

Chronic users of benzodiazepine medication who are given midazolam experience reduced therapeutic effects of midazolam, due to tolerance to benzodiazepines. Prolonged infusions with midazolam results in the development of tolerance; if midazolam is given for a few days or more a withdrawal syndrome can occur. Therefore, preventing a withdrawal syndrome requires that a prolonged infusion be gradually withdrawn, and sometimes, continued tapering of dose with an oral long-acting benzodiazepine such as clorazepate dipotassium. When signs of tolerance to midazolam occur during intensive care unit sedation the addition of an opioid or propofol is recommended. Withdrawal symptoms can include irritability, abnormal reflexes, tremors, clonus, hypertonicity, delirium and seizures, nausea, vomiting, diarrhoea, tachycardia, hypertension, and tachypnoea. In those with significant dependence, sudden discontinuation may result in withdrawal symptoms such as status epilepticus that may be fatal.

Overdose

Refer to Benzodiazepine Overdose.

A midazolam overdose is considered a medical emergency and generally requires the immediate attention of medical personnel. Benzodiazepine overdose in healthy individuals is rarely life-threatening with proper medical support; however, the toxicity of benzodiazepines increases when they are combined with other CNS depressants such as alcohol, opioids, or tricyclic antidepressants. The toxicity of benzodiazepine overdose and risk of death is also increased in the elderly and those with obstructive pulmonary disease or when used intravenously. Treatment is supportive; activated charcoal can be used within an hour of the overdose. The antidote for an overdose of midazolam (or any other benzodiazepine) is flumazenil. While effective in reversing the effects of benzodiazepines it is not used in most cases as it may trigger seizures in mixed overdoses and benzodiazepine dependent individuals.

Symptoms of midazolam overdose can include:

  • Ataxia.
  • Dysarthria.
  • Nystagmus.
  • Slurred speech.
  • Somnolence (difficulty staying awake).
  • Mental confusion.
  • Hypotension.
  • Respiratory arrest.
  • Vasomotor collapse.
  • Impaired motor functions:
    • Impaired reflexes.
    • Impaired coordination.
    • Impaired balance.
    • Dizziness.
  • Coma.
  • Death.

Detection in Body Fluids

Concentrations of midazolam or its major metabolite, 1-hydroxymidazolam glucuronide, may be measured in plasma, serum, or whole blood to monitor for safety in those receiving the drug therapeutically, to confirm a diagnosis of poisoning in hospitalised patients, or to assist in a forensic investigation of a case of fatal overdosage. Patients with renal dysfunction may exhibit prolongation of elimination half-life for both the parent drug and its active metabolite, with accumulation of these two substances in the bloodstream and the appearance of adverse depressant effects.

Interactions

Protease inhibitors, nefazodone, sertraline, grapefruit, fluoxetine, erythromycin, diltiazem, clarithromycin inhibit the metabolism of midazolam, leading to a prolonged action. St John’s wort, rifapentine, rifampin, rifabutin, phenytoin enhance the metabolism of midazolam leading to a reduced action. Sedating antidepressants, antiepileptic drugs such as phenobarbital, phenytoin and carbamazepine, sedative antihistamines, opioids, antipsychotics and alcohol enhance the sedative effects of midazolam. Midazolam is metabolised almost completely by cytochrome P450-3A4. Atorvastatin administration along with midazolam results in a reduced elimination rate of midazolam. St John’s wort decreases the blood levels of midazolam. Grapefruit juice reduces intestinal 3A4 and results in less metabolism and higher plasma concentrations.

Pharmacology

Midazolam is a short-acting benzodiazepine in adults with an elimination half-life of 1.5-2.5 hours. In the elderly, as well as young children and adolescents, the elimination half-life is longer. Midazolam is metabolised into an active metabolite alpha1-hydroxymidazolam. Age-related deficits, renal and liver status affect the pharmacokinetic factors of midazolam as well as its active metabolite. However, the active metabolite of midazolam is minor and contributes to only 10 percent of biological activity of midazolam. Midazolam is poorly absorbed orally, with only 50% of the drug reaching the bloodstream. Midazolam is metabolised by cytochrome P450 (CYP) enzymes and by glucuronide conjugation. The therapeutic as well as adverse effects of midazolam are due to its effects on the GABAA receptors; midazolam does not activate GABAA receptors directly but, as with other benzodiazepines, it enhances the effect of the neurotransmitter GABA on the GABAA receptors (↑ frequency of Cl- channel opening) resulting in neural inhibition. Almost all of the properties can be explained by the actions of benzodiazepines on GABAA receptors. This results in the following pharmacological properties being produced: sedation, induction of sleep, reduction in anxiety, anterograde amnesia, muscle relaxation and anticonvulsant effects.

Pharmacokinetics

  • Volume of Distribution: 1-2.5L/kg in normal healthy individuals.
  • Protein Binding: 96% Plasma protein bound.
  • Onset of Action: 3-15 minutes.
  • Elimination Half-Life: 1.5-3 hours.

Society and Culture

Cost

Midazolam is available as a generic medication.

Availability

Midazolam is available in the United States as a syrup or as an injectable solution.

Dormicum brand midazolam is marketed by Roche as white, oval, 7.5-mg tablets in boxes of two or three blister strips of 10 tablets, and as blue, oval, 15-mg tablets in boxes of two (Dormonid 3x) blister strips of 10 tablets. The tablets are imprinted with “Roche” on one side and the dose of the tablet on the other side. Dormicum is also available as 1-, 3-, and 10-ml ampoules at a concentration of 5 mg/ml. Another manufacturer, Novell Pharmaceutical Laboratories, makes it available as Miloz in 3- and 5-ml ampoules. Midazolam is the only water-soluble benzodiazepine available. Another maker is Roxane Laboratories; the product in an oral solution, Midazolam HCl Syrup, 2 mg/ml clear, in a red to purplish-red syrup, cherry in flavour. It becomes soluble when the injectable solution is buffered to a pH of 2.9-3.7. Midazolam is also available in liquid form. It can be administered intramuscularly, intravenously, intrathecally, intranasally, buccally, or orally.

Legal Status

In the Netherlands, midazolam is a List II drug of the Opium Law. Midazolam is a Schedule IV drug under the Convention on Psychotropic Substances. In the United Kingdom, midazolam is a Schedule 3/Class C controlled drug. In the United States, midazolam (DEA number 2884) is on the Schedule IV list of the Controlled Substances Act as a non-narcotic agent with low potential for abuse.

Marketing Authorisation

In 2011, the European Medicines Agency (EMA) granted a marketing authorisation for a buccal application form of midazolam, sold under the trade name Buccolam. Buccolam was approved for the treatment of prolonged, acute, convulsive seizures in people from three months to less than 18 years of age. This was the first application of a paediatric-use marketing authorisation.

Use in Executions

The drug has been introduced for use in executions by lethal injection in certain jurisdictions in the United States in combination with other drugs. It was introduced to replace pentobarbital after the latter’s manufacturer disallowed that drug’s use for executions. Midazolam acts as a sedative but will fail to render the condemned prisoner unconscious, at which time vecuronium bromide and potassium chloride are administered, stopping the prisoner’s breathing and heart, respectively. Due to the fact that the condemned prisoner is not unconscious but merely sedated, two very different things, those following two drugs can cause extreme pain and panic in the soon to die prisoner.

Midazolam has been used as part of a three-drug cocktail, with vecuronium bromide and potassium chloride in Florida and Oklahoma prisons. Midazolam has also been used along with hydromorphone in a two-drug protocol in Ohio and Arizona.

The usage of midazolam in executions became controversial after condemned inmate Clayton Lockett apparently regained consciousness and started speaking midway through his 2014 execution when the state of Oklahoma attempted to execute him with an untested three-drug lethal injection combination using 100 mg of midazolam. Prison officials reportedly discussed taking him to a hospital before he was pronounced dead of a heart attack 40 minutes after the execution began. An observing doctor stated that Lockett’s vein had ruptured. It is not clear whether his death was caused by one or more of the drugs or to a problem in the administration procedure, nor is it clear what quantities of vecuronium bromide and potassium chloride were released to his system before the execution was cancelled.

Notable Incidents

The state of Florida used midazolam to execute William Frederick Happ in October 2013.

The state of Ohio used midazolam in the execution of Dennis McGuire in January 2014; it took McGuire 24 minutes to die after the procedure started, and he gasped and appeared to be choking during that time, leading to questions about the dosing and timing of the drug administration, as well as the choice of drugs.

The execution of Ronald Bert Smith in the state of Alabama on 08 December 2016, “went awry soon after (midazolam) was administered” again putting the effectiveness of the drug in question.

In October 2016, the state of Ohio announced that it would resume executions in January 2017, using a formulation of midazolam, vecuronium bromide, and potassium chloride, but this was blocked by a Federal judge. On 26 July 2017, Ronald Phillips was executed with a three-drug cocktail including midazolam after the Supreme Court refused to grant a stay. Prior to this, the last execution in Ohio had been that of Dennis McGuire. Murderer Gary Otte’s lawyers unsuccessfully challenged his Ohio execution, arguing that midazolam might not protect him from serious pain when the other drugs are administered. He died without incident in about 14 minutes on 13 September 2017.

On 24 April 2017, the state of Arkansas carried out a double-execution of Jack Harold Jones, 52, and Marcel Williams, 46. The state of Arkansas attempted to execute eight people before its supply of midazolam expired on 30 April 2017. Two of them were granted a stay of execution, and another, Ledell T. Lee, 51, was executed on 20 April 2017.

On 28 October 2021, the state of Oklahoma carried out the execution of inmate John Marion Grant, 60, using midazolam as part of its three-drug cocktail hours after the US Supreme Court ruled to lift a stay of execution for Oklahoma death row inmates. The execution was the state’s first since 2015. Witnesses to the execution said that when the first drug, midazolam, began to flow at 4:09 pm, Grant started convulsing about two dozen times and vomited. Grant continued breathing, and a member of the execution team wiped the vomit off his face. At 4:15 pm., officials said Grant was unconscious, and he was pronounced dead at 4:21 pm.

Legal Challenges

In Glossip v. Gross, attorneys for three Oklahoma inmates argued that midazolam could not achieve the level of unconsciousness required for surgery, meaning severe pain and suffering was likely. They argued that midazolam was cruel and unusual punishment and thus contrary to the Eighth Amendment to the United States Constitution. In June 2015, the US Supreme Court ruled that they had failed to prove that midazolam was cruel and unusual when compared to known, available alternatives.

The state of Nevada is also known to use midazolam in execution procedures. In July 2018, one of the manufacturers accused state officials of obtaining the medication under false pretences. This incident was the first time a drug company successfully, though temporarily, halted an execution. A previous attempt in 2017, to halt an execution in the state of Arizona by another drug manufacturer was not successful.

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What is Physical Dependence?

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Introduction

Physical dependence is a physical condition caused by chronic use of a tolerance-forming drug, in which abrupt or gradual drug withdrawal causes unpleasant physical symptoms.

Physical dependence can develop from low-dose therapeutic use of certain medications such as benzodiazepines, opioids, antiepileptics and antidepressants, as well as the recreational misuse of drugs such as alcohol, opioids and benzodiazepines. The higher the dose used, the greater the duration of use, and the earlier age use began are predictive of worsened physical dependence and thus more severe withdrawal syndromes.

Acute withdrawal syndromes can last days, weeks or months. Protracted withdrawal syndrome, also known as post-acute-withdrawal syndrome or “PAWS”, is a low-grade continuation of some of the symptoms of acute withdrawal, typically in a remitting-relapsing pattern, often resulting in relapse and prolonged disability of a degree to preclude the possibility of lawful employment. Protracted withdrawal syndrome can last for months, years, or depending on individual factors, indefinitely. Protracted withdrawal syndrome is noted to be most often caused by benzodiazepines. To dispel the popular mis-association with addiction, physical dependence to medications is sometimes compared to dependence on insulin by persons with diabetes.

Symptoms

Physical dependence can manifest itself in the appearance of both physical and psychological symptoms which are caused by physiological adaptions in the central nervous system and the brain due to chronic exposure to a substance. Symptoms which may be experienced during withdrawal or reduction in dosage include increased heart rate and/or blood pressure, sweating, and tremors.[9] More serious withdrawal symptoms such as confusion, seizures, and visual hallucinations indicate a serious emergency and the need for immediate medical care.

Sedative hypnotic drugs such as alcohol, benzodiazepines, and barbiturates are the only commonly available substances that can be fatal in withdrawal due to their propensity to induce withdrawal convulsions. Abrupt withdrawal from other drugs, such as opioids can cause an extremely painful withdrawal that is very rarely fatal in patients of general good health and with medical treatment, but is more often fatal in patients with weakened cardiovascular systems; toxicity is generally caused by the often-extreme increases in heart rate and blood pressure (which can be treated with clonidine), or due to arrhythmia due to electrolyte imbalance caused by the inability to eat, and constant diarrhoea and vomiting (which can be treated with loperamide and ondansetron respectively) associated with acute opioid withdrawal, especially in longer-acting substances where the diarrhoea and emesis can continue unabated for weeks, although life-threatening complications are extremely rare, and nearly non-existent with proper medical management.

Treatment

Treatment for physical dependence depends upon the drug being withdrawn and often includes administration of another drug, especially for substances that can be dangerous when abruptly discontinued or when previous attempts have failed. Physical dependence is usually managed by a slow dose reduction over a period of weeks, months or sometimes longer depending on the drug, dose and the individual. A physical dependence on alcohol is often managed with a cross tolerant drug, such as long acting benzodiazepines to manage the alcohol withdrawal symptoms.

Drugs That Cause Physical Dependence

  • All µ-opioids with any (even slight) agonist effect, such as (partial list) morphine, heroin, codeine, oxycodone, buprenorphine, nalbuphine, methadone, and fentanyl, but not agonists specific to non-µ opioid receptors, such as salvinorin A (a k-opioid agonist), nor opioid antagonists or inverse agonists, such as naltrexone (a universal opioid inverse agonist).
  • All GABA agonists and positive allosteric modulators of both the GABA-A ionotropic receptor and GABA-B metabotropic receptor subunits, including (partial list):
  • Nicotine (tobacco) (cf. nicotine withdrawal).
  • Gabapentinoids such as gabapentin (Neurontin), pregabalin (Lyrica), and phenibut (Noofen), which are inhibitors of α2δ subunit-containing VDCCs.
  • Antiepileptic drugs such as valproate, lamotrigine, tiagabine, vigabatrin, carbamazepine and oxcarbazepine, and topiramate.
  • Antipsychotic drugs such as clozapine, risperidone, olanzapine, haloperidol, thioridazine, etc.
  • Commonly prescribed antidepressants such as the selective serotonin reuptake inhibitors (SSRIs) and serotonin-norepinephrine reuptake inhibitors (SNRIs) (cf. SSRI/SNRI withdrawal syndrome).
  • Blood pressure medications, including beta blockers such as propanolol and alpha-adrenergic agonists such as clonidine.
  • Androgenic-anabolic steroids.
  • Glucocorticoids.

Rebound Syndrome

Refer to Rebound Effect.

A wide range of drugs whilst not causing a true physical dependence can still cause withdrawal symptoms or rebound effects during dosage reduction or especially abrupt or rapid withdrawal. These can include caffeine, stimulants, steroidal drugs and antiparkinsonian drugs. It is debated whether the entire antipsychotic drug class causes true physical dependency, a subset, or if none do. But, if discontinued too rapidly, it could cause an acute withdrawal syndrome. When talking about illicit drugs rebound withdrawal, especially with stimulants, it is sometimes referred to as “coming down” or “crashing”.

Some drugs, like anticonvulsants and antidepressants, describe the drug category and not the mechanism. The individual agents and drug classes in the anticonvulsant drug category act at many different receptors and it is not possible to generalise their potential for physical dependence or incidence or severity of rebound syndrome as a group so they must be looked at individually. Anticonvulsants as a group however are known to cause tolerance to the anti-seizure effect. SSRI drugs, which have an important use as antidepressants, engender a discontinuation syndrome that manifests with physical side effects; e.g. there have been case reports of a discontinuation syndrome with venlafaxine (Effexor).

What is Nordazepam?

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Introduction

Nordazepam (INN; marketed under brand names Nordaz, Stilny, Madar, Vegesan, and Calmday; also known as nordiazepam, desoxydemoxepam, and desmethyldiazepam) is a 1,4-benzodiazepine derivative. Like other benzodiazepine derivatives, it has amnesic, anticonvulsant, anxiolytic, muscle relaxant, and sedative properties. However, it is used primarily in the treatment of anxiety disorders. It is an active metabolite of diazepam, chlordiazepoxide, clorazepate, prazepam, pinazepam, and medazepam.

Nordazepam is among the longest lasting (longest half-life) benzodiazepines, and its occurrence as a metabolite is responsible for most cumulative side-effects of its myriad of pro-drugs when they are used repeatedly at moderate-high doses; the nordazepam metabolite oxazepam is also active (and is a more potent, full benzodiazepine-site agonist), which contributes to nordazepam cumulative side-effects but occur too minutely to contribute to the cumulative side-effects of nordazepam pro-drugs (except when they are abused chronically in extremely supra-therapeutic doses).

Side effects

Common side effects of nordazepam include somnolence, which is more common in elderly patients and/or people on high-dose regimens. Hypotonia, which is much less common, is also associated with high doses and/or old age.

Contraindications and Special Caution

Benzodiazepines require special precaution if used in the elderly, during pregnancy, in children, alcohol- or drug-dependent individuals, and individuals with comorbid psychiatric disorders. As with many other drugs, changes in liver function associated with aging or diseases such as cirrhosis, may lead to impaired clearance of nordazepam.

Pharmacology

Nordazepam is a partial agonist at the GABAA receptor, which makes it less potent than other benzodiazepines, particularly in its amnesic and muscle-relaxing effects. Its elimination half life is between 36 and 200 hours, with wide variation among individuals; factors such as age and gender are known to impact it. The variation of reported half-lives are attributed to differences in nordazepam metabolism and that of its metabolites as nordazepam is hydroxylated to active metabolites such as oxazepam, before finally being glucuronidated and excreted in the urine. This can be attributed to extremely variable hepatic and renal metabolic functions among individuals depending upon a number of factors (including age, ethnicity, disease, and current or previous use/abuse of other drugs/medicines).

Pregnancy and Nursing Mothers

Nordazepam, like other benzodiazepines, easily crosses the placental barrier, so the drug should not be administered during the first trimester of pregnancy. In case of serious medical reasons, nordazepam can be given in late pregnancy, but the foetus, due to the pharmacological action of the drug, may experience side effects such as hypothermia, hypotonia, and sometimes mild respiratory depression. Since nordazepam and other benzodiazepines are excreted in breast milk, the substance should not be administered to mothers who are breastfeeding. Discontinuing of breast-feeding is indicated for regular intake by the mother.

Recreational Use

Refer to Benzodiazepine Use Disorder.

Nordazepam and other sedative-hypnotic drugs are detected frequently in cases of people suspected of driving under the influence of drugs. Many drivers have blood levels far exceeding the therapeutic dose range, suggesting benzodiazepines are commonly used in doses higher than the recommended doses.

What is Fosazepam?

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Introduction

Fosazepam is a drug which is a benzodiazepine derivative; it is a water soluble derivative of diazepam. It has sedative and anxiolytic effects, and is a derivative of diazepam which has been substituted with a dimethylphosphoryl group to improve solubility in water.

Background

Fosazepam has similar effects on sleep as other benzodiazepines. In a clinical trial it was reported that fosazepam to lead to increased sleep duration with less broken sleep but sleep quality was worsened with suppressed deep sleep and increased light sleep. Adverse effects included feelings of impaired morning vitality and upon discontinuing the drug benzodiazepine withdrawal symptoms of anxiety, impaired concentration and impaired morning vitality were experienced. Another clinical trial also found worsening of sleep while on benzodiazepines as well as during withdrawal with suppression of deep sleep stages including REM (rapid eye movement) sleep, with increased light sleep upon withdrawal. The main metabolites of fosazepam are 3-hydroxyfosazepam and the active metabolite desmethyldiazepam which has a very long elimination half-life of about 3 days. Tolerance to the hypnotic effects of fosazepam starts to develop after about 7 days of use. Due to the very long elimination half-life of the active metabolite of fosazepam it is not recommended for use as a hypnotic. The main pharmacological effects of fosazepam may be due to its metabolite nordiazepam (desmethyldiazepam), rather than the parent drug. The long-acting active metabolite nordazepam (refer to nordiazepam) can cause extended sedative effects at high doses or with prolonged use, and may produce residual sedation upon awakening.

Fosazepam is of relatively low potency compared to other benzodiazepine derivatives, with a 100 mg dose of fosazepam equivalent to 10 mg of nitrazepam. 60 mg of fosazepam has also been estimated to be equivalent to about 5-10 mg of diazepam. Fosazepam has similar effects to nitrazepam, but with a shorter duration of action and less tendency to cause over sedation, motor-impairment, amnesia, rebound insomnia, and morning grogginess.