Tag: Medication

What is Nefazodone?

Published on by Andrew Marshall13 Comments

Introduction

Nefazodone, sold formerly under the brand names Serzone, Dutonin, and Nefadar among others, is an atypical antidepressant which was first marketed by Bristol-Myers Squibb (BMS) in 1994 but has since largely been discontinued.

BMS withdrew it from the market by 2004 due to decreasing sales due to the rare incidence of severe liver damage and the onset of generic competition. The incidence of severe liver damage is approximately 1 in every 250,000 to 300,000 patient-years. Generic versions were introduced in 2003.

Nefazodone is a phenylpiperazine compound and is related to trazodone. It has been described as a serotonin antagonist and reuptake inhibitor (SARI) due to its combined actions as a potent serotonin 5-HT2A receptor and 5-HT2C receptor antagonist and weak serotonin-norepinephrine-dopamine reuptake inhibitor (SNDRI).

Brief History

Nefazodone was discovered by scientists at Bristol-Myers Squibb (BMS) who were seeking to improve on trazodone by reducing its sedating qualities.

BMS obtained marketing approvals worldwide for nefazodone in 1994. It was marketed in the US under the brand name Serzone and in Europe under the brand name Dutonin.

In 2002, the US Food and Drug Administration (FDA) obligated BMS to add a black box warning about potential fatal liver toxicity to the drug label. Worldwide sales in 2002 were $409 million.

In 2003 Public Citizen filed a citizen petition asking the FDA to withdraw the marketing authorisation in the US, and in early 2004 the organisation sued the FDA to attempt to force withdrawal of the drug. The FDA issued a response to the petition in June 2004 and filed a motion to dismiss, and Public Citizen withdrew the suit.

Generic versions were introduced in the US in 2003 and Health Canada withdrew the marketing authorization that year.

Sales of nefazodone were about $100 million in 2003. By that time it was also being marketed under the additional brand names Serzonil, Nefadar, and Rulivan.

In April 2004, BMS announced that it was going discontinue the sale of Serzone in the US in June 2004 and said that this was due to declining sales. By that time BMS had already withdrawn the drug from the market in Europe, Australia, New Zealand and Canada.

As of 2012 generic nefazodone was available in the US.

Medical Uses

Nefazodone is used to treat major depressive disorder, aggressive behaviour, and panic disorder.

Available Forms

Nefazodone is available as 50 mg, 100 mg, 150 mg, 200 mg, and 250 mg tablets for oral ingestion.

Side Effects

Nefazodone can cause severe liver damage, leading to a need for liver transplant, and death. The incidence of severe liver damage is approximately 1 in every 250,000 to 300,000 patient-years. By the time that it started to be withdrawn in 2003, nefazodone had been associated with at least 53 cases of liver injury, with 11 deaths, in the United States, and 51 cases of liver toxicity, with 2 cases of liver transplantation, in Canada. In a Canadian study which found 32 cases in 2002, it was noted that databases like that used in the study tended to include only a small proportion of suspected drug reactions.

Common and mild side effects of nefazodone reported in clinical trials more often than placebo include dry mouth (25%), sleepiness (25%), nausea (22%), dizziness (17%), blurred vision (16%), weakness (11%), lightheadedness (10%), confusion (7%), and orthostatic hypotension (5%). Rare and serious adverse reactions may include allergic reactions, fainting, painful/prolonged erection, and jaundice.

Nefazodone is not especially associated with increased appetite and weight gain.

Interactions

Nefazodone is a potent inhibitor of CYP3A4, and may interact adversely with many commonly used medications that are metabolized by CYP3A4.

Pharmacology

Pharmacodynamics

Nefazodone acts primarily as a potent antagonist of the serotonin 5-HT2A receptor and to a lesser extent of the serotonin 5-HT2C receptor. It also has high affinity for the α1-adrenergic receptor and serotonin 5-HT1A receptor, and relatively lower affinity for the α2-adrenergic receptor and dopamine D2 receptor. Nefazodone has low but significant affinity for the serotonin, norepinephrine, and dopamine transporters as well, and therefore acts as a weak serotonin-norepinephrine-dopamine reuptake inhibitor (SNDRI). It has low but potentially significant affinity for the histamine H1 receptor, where it is an antagonist, and hence may have some antihistamine activity. Nefazodone has negligible activity at muscarinic acetylcholine receptors, and accordingly, has no anticholinergic effects.

Pharmacokinetics

The bioavailability of nefazodone is low and variable, about 20%. Its plasma protein binding is approximately 99%, but it is bound loosely.

Nefazodone is metabolized in the liver, with the main enzyme involved thought to be CYP3A4. The drug has at least four active metabolites, which include hydroxynefazodone, para-hydroxynefazodone, triazoledione, and meta-chlorophenylpiperazine. Nefazodone has a short elimination half-life of about 2 to 4 hours. Its metabolite hydroxynefazodone similarly has an elimination half-life of about 1.5 to 4 hours, whereas the elimination half-lives of triazoledione and mCPP are longer at around 18 hours and 4 to 8 hours, respectively. Due to its long elimination half-life, triazole is the major metabolite and predominates in the circulation during nefazodone treatment, with plasma levels that are 4 to 10 times higher than those of nefazodone itself. Conversely, hydroxynefazodone levels are about 40% of those of nefazodone at steady state. Plasma levels of mCPP are very low at about 7% of those of nefazodone; hence, mCPP is only a minor metabolite. mCPP is thought to be formed from nefazodone specifically by CYP2D6.

The ratios of brain-to-plasma concentrations of mCPP to nefazodone are 47:1 in mice and 10:1 in rats, suggesting that brain exposure to mCPP may be much higher than plasma exposure. Conversely, hydroxynefazodone levels in the brain are 10% of those in plasma in rats. As such, in spite of its relatively low plasma concentrations, brain exposure to mCPP may be substantial, whereas that of hydroxynefazodone may be minimal.

Chemistry

Nefazodone is a phenylpiperazine; it is an alpha-phenoxyl derivative of etoperidone which in turn was a derivative of trazodone.

Society and Culture

Generic Names

Nefazodone is the generic name of the drug and its INN and BAN, while néfazodone is its DCF and nefazodone hydrochloride is its USAN and USP.

Brand Names

Nefazodone has been marketed under a number of brand names including Dutonin (AT, ES, IE, UK), Menfazona (ES), Nefadar (CH, DE, NO, SE), Nefazodone BMS (AT), Nefazodone Hydrochloride Teva (US), Reseril (IT), Rulivan (ES), and Serzone (AU, CA, US). As of 2017, it remains available only on a limited basis as Nefazodone Hydrochloride Teva in the United States.

Research

The use of nefazodone to prevent migraine has been studied, due to its antagonistic effects on the 5-HT2A and 5-HT2C receptors.

What is Gidazepam?

Published on by Andrew MarshallLeave a comment

Introdction

Gidazepam, also known as hydazepam or hidazepam, is a drug which is an atypical benzodiazepine derivative, developed in the Soviet Union.

Background

It is a selectively anxiolytic benzodiazepine. It also has therapeutic value in the management of certain cardiovascular disorders. It can also be used for a treatment to giddiness.

Gidazepam is a prodrug for its active metabolite 7-bromo-5-phenyl-1,2-dihydro-3H-1,4-benzodiazepine-2-one (desalkylgidazepam or bromo-nordazepam). It is used as an antianxiety drug. Its anxiolytic effects can take several hours to manifest after dosing however, as it is the active metabolite which primarily gives the anxiolytic effects, and Gidazepam’s half-life is among the longest of all GABA-ergic agonists.

What is Phenazepam?

Published on by Andrew Marshall3 Comments

Introduction

Phenazepam (also known in Russia as bromdihydrochlorphenylbenzodiazepine) is a benzodiazepine drug, which was developed in the Soviet Union in 1975, and now produced in Russia and some CIS countries.

Phenazepam is used in the treatment of various mental disorders such as psychiatric schizophrenia and anxiety. It can be used as a premedication before surgery as it augments the effects of anaesthetics. Recently, phenazepam has gained popularity as a recreational drug; misuse has been reported in the United Kingdom, Finland, Sweden, and the United States.

Refer to 3-Hydroxyphenazepam and Cinazepam.

Indications

  • Neurosis, neurosis-like, psychopathic (personality disorder), psychopathic-like and other conditions accompanied by fear, anxiety, increased irritability, and emotional lability.
  • Brief reactive psychosis and hypochondriasis-senestopathic syndrome.
  • Vegetative dysfunction and vegetative lability.
  • Insomnia.
  • Alcohol withdrawal syndrome.
  • Temporal lobe epilepsy and myoclonic epilepsy (used only occasionally as better options exist).
  • Hyperkinesia and tics.
  • Muscle spasticity.

Usually, a course of treatment with phenazepam should not normally exceed 2 weeks (in some cases therapy may be prolonged for up to 2 months) due to the risk of drug abuse and dependence. To prevent withdrawal syndrome, it is necessary to reduce the dose gradually.

Chemistry

Phenazepam is a drug of the benzodiazepine class. Benzodiazepine drugs contain a benzene ring fused to a diazepine ring, which is a seven membered ring with the two nitrogen constituents located at R1 and R4. The benzyl ring of phenazepam is substituted at R7 with a bromine group. Like most benzodiazepines, phenazepam has a phenyl ring in R5 which is substituted by chlorine in the R2′ group. Phenazepam also contains an oxygen group double bonded to R2 of its diazepine ring to form a ketone. This oxygen substitution at R2 is shared with other benzodiazepine drugs with the suffix -azepam.

Like other benzodiazepines, phenazepam (7-bromo-5-(2-chlorophenyl)-1,3-dihydro-1,4-benzodiazepin-2-one) is composed of a benzene ring fused to a seven-membered 1,4-diazepine ring. A 2-chlorophenyl ring is attached at the 5-position and a bromine is attached at the 7-position. Phenazepam has a molecular formula of C15H10BrClN2O and a molecular weight of 349.6 g/mol.

Side Effects

Side effects include hiccups, dizziness, loss of coordination and drowsiness, along with anterograde amnesia which can be quite pronounced at high doses. As with other benzodiazepines, in case of abrupt discontinuation following prolonged use, severe withdrawal symptoms may occur including restlessness, anxiety, insomnia, seizures, convulsions and death, though because of its intermediate half-life as well as that of its active metabolites, these withdrawal symptoms may take two or more days to manifest.

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.

Phenazepam should not be taken with alcohol or any other CNS depressants. Phenazepam should not be used therapeutically for periods of longer than one month including tapering on and off the drug as recommended for any benzodiazepine in the British national formulary. Some patients may require longer term treatment.

Phenazepam was found to be a component in some herbal incense mixtures in Australia and New Zealand in 2011, namely “Kronic”. The particular product variety was withdrawn shortly from the market after and replaced with a new formulation.

Synthesis

First, 2-(o-chlorobenzoylamino)-5-bromo-2-chlorobenzophenone is prepared by acylation of p-bromoaniline with o-chlorobenzoic acid acyl chloride in the presence of a zinc chloride catalyst. This is hydrolysed with aqueous sulfuric acid to yield 2-amino-5-bromo-2′-chlorobenzophenone, which is then acylated with hydrochloride of aminoacetic acid acyl chloride in chloroform to form 2-(aminomethylkarbonylamino)-5-bromo-2-chlorobenzophenone hydrochloride, which is converted to a base with aqueous ammonia and then thermally cyclized to bromodihydrochlorophenylbenzodiazepine (phenazepam).

Hydrochloride of aminoacetic acid acyl chloride is prepared by chemical treating glycine with phosphorus pentachloride (PCl5) in chloroform.

This method of Phenazepam synthesis was developed in the 1970s at the Physico-Chemical Institute of the Academy of Sciences of the Ukrainian SSR.

Detection in Biological Fluids

Phenazepam may be measured in blood or plasma by chromatographic methods. Blood phenazepam concentrations are typically less than 30 μg/L during therapeutic usage, but have frequently been in the 100–600 μg/L range in automotive vehicle operators arrested for impaired driving ability.

China

As of October 2015, phenazepam is a controlled substance in China.

United States

Under federal United States law, phenazepam is not currently classified as a controlled substance, as the Federal Analog Act only provides for automatic assumed classification of chemicals “substantially similar” to existing Schedule I or Schedule II drugs, whereas all controlled benzodiazepines under the Controlled Substances Act are classified as Schedule IV. Although phenazepam is currently not controlled, sale for human use remains illegal in the United States. Suppliers attempt to circumvent this regulation by placing a “Not for human use” disclaimer on the product’s label.

Individual states in the United States often ban these analogue drugs by name as they appear. Since 2012, Louisiana has classified phenazepam as a controlled dangerous substance. This ban affects several products, some of which were sold at retail stores under the guise of air freshener or similar, containing phenazepam yet claiming not to be for human use. This legislation was introduced after one such product, branded as “Zannie” and marketed as an air freshener rapidly gained publicity as the subject of numerous media reports, attracting the attention of officials. The ensuing investigation effort, led by Senator Fred Mills and Louisiana Poison Centre Director Mark Ryan, positively identified the active ingredient of “Zannie” as phenazepam. According to Ryan, chemical analysis identified the active ingredient as “100 percent phenazepam”.

Paul Halverson, director and state health officer for the Arkansas Department of Health, approved an emergency rule to ban the sale and distribution of phenazepam shortly after the Louisiana ban.

United Kingdom

Phenazepam is a class C drug in the UK.

The UK home office banned importation of phenazepam on Friday 22 July 2011 while it drafted legislation, released in January 2012 to become law at the end of March 2012. The bill was quashed following advice from the ACMD as it included two non-abusable steroids. There was a new discussion about its fate on 23 April 2012, where it was decided that the bill would be rewritten and phenazepam would still be banned.

It was eventually banned on 13 June 2012 as a class C, schedule II drug.

Elsewhere

Phenazepam was classified as a narcotic in Finland in July 2014.

Phenazepam is considered a narcotic in Norway, as per a 23 March 2010 Health Department addition to the Regular Narcotic List.

In Russia, while the drug is considered a prescription medication (but not a controlled one, as all other benzodiazepines except tofisopam), some pharmacies sell it without prescriptions required. Since 22 March 2021 phenazepam must be a controlled substance in Russia.

In Estonia, phenazepam is a Schedule IV substance under the Narcotic Drugs and Psychotropic Substances Act. Schedule IV is the lowest classification of psychoactive substances in Estonia. It includes prescribed drugs, including other benzodiazepines.

UN Single Convention on Narcotic Drugs
On 8 March 2016 at its 59th Session, the Commission on Narcotic Drugs (CND) added Phenazepam to relevant schedules of the Single Convention on Narcotic Drugs of 1961.[33]

Trade Names

Russia:

  • «Феназепам» (Phenazepam) tablets 0.25, 0.5 and 1 mg, solution for intramuscular and intravenous injection 1 mg/mL (0.1%).
  • «Элзепам» (Elzepam) tablets 0.5 and 1 mg, solution for intramuscular and intravenous injection 1 mg/mL (0.1%).
  • «Фензитат» (Phenzitat) tablets 0.5 and 1 mg.
  • «Фенорелаксан» (Phenorelaxan) tablets 0.5 and 1 mg, solution for intramuscular and intravenous injection 1 mg/mL (0.1%).
  • «Транквезипам» (Trankvezipam) tablets 0.5 and 1 mg, solution for intramuscular and intravenous injection 1 mg/mL (0.1%).
  • «Фезипам» (Phezipam) tablets 0.5 and 1 mg (not to be confused with «Фезам» (Phezam) which contains cinnarizine/piracetam).
  • «Фезанеф» (Phezanef) tablets 1 mg.

What is Cinazepam?

Published on by Andrew Marshall2 Comments

Introduction

Cinazepam (BD-798, sold under brand name Levana) is an atypical benzodiazepine derivative.

Background

It produces pronounced hypnotic, sedative, and anxiolytic effects with minimal myorelaxant side effects. In addition, unlike many other benzodiazepine and nonbenzodiazepine hypnotics such as diazepam, flunitrazepam, and zopiclone, cinazepam does not violate sleep architecture, and the continuity of slow-wave sleep and REM sleep are proportionally increased. As such, cinazepam produces a sleep state close to physiological, and for that reason, may be advantageous compared to other, related drugs in the treatment of insomnia and other sleep disorders.

Cinazepam has an order of magnitude lower affinity for the benzodiazepine receptor of the GABAA complex relative to other well-known hypnotic benzodiazepines such as nitrazepam and phenazepam. Moreover, in mice, it is rapidly metabolised, with only 5% of the base compound remaining within 30 minutes of administration. As such, cinazepam is considered to be a benzodiazepine prodrug; specifically, to 3-hydroxyphenazepam, as the main active metabolite.

What is 3-Hydroxyphenazepam?

Published on by Andrew Marshall2 Comments

Introduction

3-Hydroxyphenazepam is a benzodiazepine with hypnotic, sedative, anxiolytic, and anticonvulsant properties.

Background

It is an active metabolite of phenazepam, as well as the active metabolite of the benzodiazepine prodrug cinazepam. Relative to phenazepam, 3-hydroxyphenazepam has diminished myorelaxant properties, but is about equivalent in most other regards.

Like other benzodiazepines, 3-hydroxyphenazepam behaves as a positive allosteric modulator of the benzodiazepine site of the GABAA receptor with an EC50 value of 10.3 nM.

It has been sold online as a designer drug.

What is Flutemazepam?

Published on by Andrew MarshallLeave a comment

Introduction

Flutemazepam was developed at a team at Stabilimenti Chimici Farmaceutici Riuniti SpA in the mid 1970s.

Background

It is a drug which is a 3-hydroxy benzodiazepine derivative and an analogue of temazepam that has hypnotic, sedative, amnesiac, anxiolytic, anticonvulsant and skeletal muscle relaxant properties. It is most closely related in structure to temazepam and is indicated for the treatment of severe insomnia. Flutemazepam has properties similar to temazepam, and it has been found to be very effective for the treatment of severe states of anxiety, panic attacks, and severe insomnia.