Brands, Medical Use, Clinical Data
Drug Category
- Anti-anxiety Agents
- Adjuvants, Anesthesia
- Benzodiazepines
- GABA Modulators
Dosage Forms
- Capsule (7.5 mg, 15 mg, and 30 mg)
Brands / Synonyms
Apo-Temazepam; Cerepax; Crisonar; Euhypnos; Euipnos; Gelthix; Hydroxydiazepam; Levanxene; Levanxol; Levanzene; Mabertin; Methyloxazepam; N-Methyloxazepam; Normison; Novo-Temazepam; Oxydiazepam; Perdorm; Planum; Remestan; Restoril; Signopam; Temaz
Indications
For the short-term treatment of insomnia (generally 7-10 days).
Pharmacology
Temazepam is a benzodiazepine used as a hypnotic agent in the management of insomnia. Temazepam produces CNS depression at limbic, thalamic, and hypothalamic levels of the CNS. Temazepam increases the affinity of the neurotransmitter gamma-aminobutyric acid (GABA) for GABA receptors by binding to benzodiazepine receptors. Results are sedation, hypnosis, skeletal muscle relaxation, anticonvulsant activity, and anxiolytic action.
Mechanism of Action
Benzodiazepines bind nonspecifically to benzodiazepine receptors, which affects affects muscle relaxation, anticonvulsant activity, motor coordination, and memory. As benzodiazepine receptors are thought to be coupled to gamma-aminobutyric acid-A (GABAA) receptors, this enhances the effects GABA by increasing GABA affinity for the GABA receptor. Binding of the inhibitory neurotransmitter GABA to the site opens the chloride channel, resulting in a hyperpolarized cell membrane that prevents further excitation of the cell.
Absorption
Well absorbed, minimal first-pass metabolism.
Toxicity
Not Available
Biotrnasformation / Drug Metabolism
Hepatic. Temazepam is completely metabolized through conjugation prior to excretion. The major metabolite is the O-conjugate of temazepam (90%).
Contraindications
Benzodiazepines may cause fetal damage when administered during pregnancy. An increased risk of congenital
malformations associated with the use of diazepam and chlordiazepoxide during the first trimester of pregnancy has
been suggested in several studies. Transplacental distribution has resulted in neonatal CNS depression following the
ingestion of therapeutic doses of a benzodiazepine hypnotic during the last weeks of pregnancy.
Reproduction studies in animals with temazepam were performed in rats and rabbits. In a perinatal-postnatal study
in rats, oral doses of 60 mg/kg/day resulted in increasing nursling mortality. Teratology studies in rats
demonstrated increased fetal resorptions at doses of 30 and 120 mg/kg in one study and increased occurrence of
rudimentary ribs, which are considered skeletal variants, in a second study at doses of 240 mg/kg or higher. In
rabbits, occasional abnormalities such as exencephaly and fusion or asymmetry of ribs were reported without dose
relationship. Although these abnormalities were not found in the concurrent control group, they have been reported to
occur randomly in historical controls. At doses of 40 mg/kg or higher, there was an increased incidence of the 13th
rib variant when compared to the incidence in concurrent and historical controls.
Temazepam is contraindicated in pregnant women. If there is a likelihood of the patient becoming pregnant while
receiving temazepam, she should be warned of the potential risk to the fetus. Patients should be instructed to
discontinue the drug prior to becoming pregnant. The possibility that a woman of childbearing potential may be
pregnant at the time of institution of therapy should be considered.
Drug Interactions
The pharmacokinetic profile of temazepam does not appear to be altered by orally administered cimetidine dosed
according to labeling.
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