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Routes of administration | Oral |
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Pharmacokinetic data | |
Bioavailability | 90% |
Metabolism | Hepatic |
Elimination half-life | 6,4-10,5 hours |
Excretion | Renal |
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ECHA InfoCard | 100.048.046 |
Chemical and physical data | |
Formula | C19H18ClN3O3 |
Molar mass | 371.82 g·mol−1 |
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Camazepam [2] is a benzodiazepine psychoactive drug, marketed under the brand names Albego, Limpidon and Paxor. It is the dimethyl carbamate ester of temazepam, a metabolite of diazepam. [3] While it possesses anxiolytic, anticonvulsant, skeletal muscle relaxant and hypnotic properties [4] it differs from other benzodiazepines in that its anxiolytic properties are particularly prominent but has comparatively limited anticonvulsant, hypnotic and skeletal muscle relaxant properties.
Camazepam, like others benzodiazepines, produce a variety of therapeutic and adverse effects by binding to the benzodiazepine receptor site on the GABAA receptor and modulating the function of the GABA receptor, the most prolific inhibitory receptor within the brain. The GABA chemical and receptor system mediates inhibitory or calming effects of camazepam on the nervous system. Compared to other benzodiazepines, it has reduced side effects such as impaired cognition, reaction times and coordination, [5] [6] [7] [8] [9] which makes it best suited as an anxiolytic because of these reduced sides effects. Animal studies have shown camazepam and its active metabolites possess anticonvulsant properties. [10] Unlike other benzodiazepines it does not disrupt normal sleep patterns. [11] Camazepam has been shown in animal experiments to have a very low affinity for benzodiazepine receptors compared to other benzodiazepines. [12] Compared to temazepam, camazepam has shown roughly equal anxiolytic properties, and less anticonvulsant, sedative, and motor-impairing properties.
Following oral administration, camazepam is almost completely absorbed into the bloodstream, with 90 percent bioavailability achieved in humans. [13] In the human camazepam is metabolised into the active metabolite temazepam. [14] Studies in dogs have shown that the half-life of the terminal elimination phase ranged from 6.4 to 10.5 h. [15]
Camazepam is indicated for the short-term treatment of insomnia and anxiety. [16] As with other benzodiazepines, its use should be reserved for patients in which the sleep disorder is severe, disabling, or causes marked distress. [17]
With higher doses, such as 40 mg of camazepam, impairments similar to those caused by other benzodiazepines manifest as disrupted sleep patterns and impaired cognitive performance. [18] Skin disorders have been reported with use of camazepam however. [19] One study has shown that camazepam may increase attention. [20]
Research has demonstrated that Camazepam exhibits competitive binding to benzodiazepine receptors within the brain, albeit with a relatively modest affinity in animal models. This interaction with benzodiazepine receptors, facilitated by both Camazepam and its active metabolites, is accountable for the medication's anticonvulsant properties.
Use of camazepam is contraindicated in subjects with known hypersensitivity to drug or allergy to other drugs in the benzodiazepine class or any excipients contained in the pharmaceutical form. Use of camazepam should be avoided or carefully monitored by medical professionals in individuals with the following conditions: myasthenia gravis, severe liver deficiencies (e.g., cirrhosis), severe sleep apnea, pre-existing respiratory depression or cronic pulmonary insufficiency. [21]
Diazepam, first marketed as Valium, is a medicine of the benzodiazepine family that acts as an anxiolytic. It is commonly used to treat a range of conditions, including anxiety, seizures, alcohol withdrawal syndrome, muscle spasms, insomnia, and restless legs syndrome. It may also be used to cause memory loss during certain medical procedures. It can be taken orally, as a suppository inserted into the rectum, intramuscularly, intravenously or used as a nasal spray. When injected intravenously, effects begin in one to five minutes and last up to an hour. Orally, effects begin after 15 to 60 minutes.
Temazepam is a medication of the benzodiazepine class which is generally used to treat severe or debilitating insomnia. It is taken by mouth. Temazepam is rapidly absorbed, and significant hypnotic effects begin in less than 30 minutes and can last for up to eight hours. Many studies, some going as far back as the early 1980s out of Australia and the United Kingdom, both of which have had serious temazepam abuse epidemics and related mortality, have all mostly corroborated each other and proven that the potential for abuse and physical dependence is very high, even in comparison to many other benzodiazepines. As a result, prescriptions for hypnotics such as temazepam have seen a dramatic decrease since 2010, while anxiolytics such as alprazolam (Xanax), clonazepam, and lorazepam (Ativan) have increased or remained stable. Temazepam and similar hypnotics, such as triazolam (Halcion) are generally reserved for severe and debilitating insomnia. They have largely been replaced by z-drugs and atypical antidepressants as first line treatment for insomnia.
Nitrazepam, sold under the brand name Mogadon among others, is a hypnotic drug of the benzodiazepine class used for short-term relief from severe, disabling anxiety and insomnia. It also has sedative (calming) properties, as well as amnestic, anticonvulsant, and skeletal muscle relaxant effects.
Flurazepam is a drug which is a benzodiazepine derivative. It possesses anxiolytic, anticonvulsant, hypnotic, sedative and skeletal muscle relaxant properties. It produces a metabolite with a long half-life, which may stay in the bloodstream for days. Flurazepam was patented in 1968 and came into medical use the same year. Flurazepam, developed by Roche Pharmaceuticals was one of the first benzo hypnotics to be marketed.
Quazepam, sold under brand name Doral among others, is a relatively long-acting benzodiazepine derivative drug developed by the Schering Corporation in the 1970s. Quazepam is used for the treatment of insomnia including sleep induction and sleep maintenance. Quazepam induces impairment of motor function and has relatively selective hypnotic and anticonvulsant properties with considerably less overdose potential than other benzodiazepines. Quazepam is an effective hypnotic which induces and maintains sleep without disruption of the sleep architecture.
Nordazepam 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.
Prazepam is a benzodiazepine derivative drug developed by Warner-Lambert in the 1960s. It possesses anxiolytic, anticonvulsant, sedative and skeletal muscle relaxant properties. Prazepam is a prodrug for desmethyldiazepam which is responsible for the therapeutic effects of prazepam.
Nimetazepam is an intermediate-acting hypnotic drug which is a benzodiazepine derivative. It was first synthesized by a team at Hoffmann-La Roche in 1964. It possesses powerful hypnotic, anxiolytic, sedative, and skeletal muscle relaxant properties. Nimetazepam is also a particularly potent anticonvulsant. It is marketed in 5 mg tablets known as Erimin, which is the brand name manufactured and marketed by the large Japanese corporation Sumitomo. Japan is the sole manufacturer of nimetazepam in the world. Outside of Japan, Erimin is available in much of East and Southeast Asia and was widely prescribed for the short-term treatment of severe insomnia in patients who have difficulty falling asleep or maintaining sleep. Sumitomo has ceased manufacturing Erimin since November 2015. It is still available as a generic drug or as Lavol.
Pinazepam is a benzodiazepine drug. It possesses anxiolytic, anticonvulsant, sedative and skeletal muscle relaxant properties.
Ethyl loflazepate is a drug which is a benzodiazepine derivative. It possesses anxiolytic, anticonvulsant, sedative and skeletal muscle relaxant properties. In animal studies it was found to have low toxicity, although in rats evidence of pulmonary phospholipidosis occurred with pulmonary foam cells developing with long-term use of very high doses. Its elimination half-life is 51–103 hours. Its mechanism of action is similar to other benzodiazepines. Ethyl loflazepate also produces an active metabolite which is stronger than the parent compound. Ethyl loflazepate was designed to be a prodrug for descarboxyloflazepate, its active metabolite. It is the active metabolite which is responsible for most of the pharmacological effects rather than ethyl loflazepate. The main metabolites of ethyl loflazepate are descarbethoxyloflazepate, loflazepate and 3-hydroxydescarbethoxyloflazepate. Accumulation of the active metabolites of ethyl loflazepate are not affected by those with kidney failure or impairment. The symptoms of an overdose of ethyl loflazepate include sleepiness, agitation and ataxia. Hypotonia may also occur in severe cases. These symptoms occur much more frequently and severely in children. Death from therapeutic maintenance doses of ethyl loflazepate taken for 2 – 3 weeks has been reported in 3 elderly patients. The cause of death was asphyxia due to benzodiazepine toxicity. High doses of the antidepressant fluvoxamine may potentiate the adverse effects of ethyl loflazepate.
Etizolam is a thienodiazepine derivative which is a benzodiazepine analog. The etizolam molecule differs from a benzodiazepine in that the benzene ring has been replaced by a thiophene ring and triazole ring has been fused, making the drug a thienotriazolodiazepine.
Clotiazepam is a thienodiazepine drug which is a benzodiazepine analog. The clotiazepam molecule differs from benzodiazepines in that the benzene ring has been replaced by a thiophene ring. It possesses anxiolytic, skeletal muscle relaxant, anticonvulsant, sedative properties. Stage 2 NREM sleep is significantly increased by clotiazepam.
Lormetazepam, sold under the brand name Noctamid among others, is a drug which is a short to intermediate acting 3-hydroxy benzodiazepine derivative and temazepam analogue. It possesses hypnotic, anxiolytic, anticonvulsant, sedative, and skeletal muscle relaxant properties.
Brotizolam is a sedative-hypnotic thienotriazolodiazepine drug which is a benzodiazepine analog. It possesses anxiolytic, anticonvulsant, hypnotic, sedative and skeletal muscle relaxant properties, and is considered to be similar in effect to other short-acting hypnotic benzodiazepines such as triazolam or midazolam. It is used in the short-term treatment of severe insomnia. Brotizolam is a highly potent and short-acting hypnotic, with a typical dose ranging from 0.125 to 0.25 milligrams, which is rapidly eliminated with an average half-life of 4.4 hours.
Doxefazepam is a benzodiazepine medication It possesses anxiolytic, anticonvulsant, sedative and skeletal muscle relaxant properties. It is used therapeutically as a hypnotic. According to Babbini and colleagues in 1975, this derivative of flurazepam was between 2 and 4 times more potent than the latter while at the same time being half as toxic in laboratory animals.
Bretazenil (Ro16-6028) is an imidazopyrrolobenzodiazepine anxiolytic drug which is derived from the benzodiazepine family, and was invented in 1988. It is most closely related in structure to the GABA antagonist flumazenil, although its effects are somewhat different. It is classified as a high-potency benzodiazepine due to its high affinity binding to benzodiazepine binding sites where it acts as a partial agonist. Its profile as a partial agonist and preclinical trial data suggests that it may have a reduced adverse effect profile. In particular bretazenil has been proposed to cause a less strong development of tolerance and withdrawal syndrome. Bretazenil differs from traditional 1,4-benzodiazepines by being a partial agonist and because it binds to α1, α2, α3, α4, α5 and α6 subunit containing GABAA receptor benzodiazepine receptor complexes. 1,4-benzodiazepines bind only to α1, α2, α3 and α5GABAA benzodiazepine receptor complexes.
DMCM is a drug from the β-carboline family that induces anxiety and convulsions by acting as a negative allosteric modulator of GABAA receptors — functionally opposite to benzodiazepines and related drugs which are positive allosteric modulators — and is used in scientific research for these properties to test new anxiolytic and anticonvulsant medications, respectively. It has also been shown to produce analgesic effects in animals, which is thought to be the drug's induced panic reducing the perception of pain.
Delorazepam, also known as chlordesmethyldiazepam and nordiclazepam, is a drug which is a benzodiazepine and a derivative of desmethyldiazepam. It is marketed in Italy, where it is available under the trade name EN and Dadumir. Delorazepam (chlordesmethyldiazepam) is also an active metabolite of the benzodiazepine drugs diclazepam and cloxazolam. Adverse effects may include hangover type effects, drowsiness, behavioural impairments and short-term memory impairments. Similar to other benzodiazepines delorazepam has anxiolytic, skeletal muscle relaxant, hypnotic and anticonvulsant properties.
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.
Metaclazepam is a drug which is a benzodiazepine derivative. It is a relatively selective anxiolytic with less sedative or muscle relaxant properties than other benzodiazepines such as diazepam or bromazepam. It has an active metabolite N-desmethylmetaclazepam, which is the main metabolite of metaclazepam. There is no significant difference in metabolism between younger and older individuals.