TEMAZEPAM — temazepam capsule
Alembic Pharmaceuticals Inc.
WARNING: RISKS FROM CONCOMITANT USE WITH OPIOIDS; ABUSE, MISUSE, AND ADDICTION; and DEPENDENCE AND WITHDRAWAL REACTIONS
- Concomitant use of benzodiazepines and opioids may result in profound sedation, respiratory depression, coma, and death. Reserve concomitant prescribing of these drugs in patients for whom alternative treatment options are inadequate. Limit dosages and durations to the minimum required. Follow patients for signs and symptoms of respiratory depression and sedation (see WARNINGS and PRECAUTIONS).
- The use of benzodiazepines, including temazepam capsules, exposes users to risks of abuse, misuse, and addiction, which can lead to overdose or death. Abuse and misuse of benzodiazepines commonly involve concomitant use of other medications, alcohol, and/or illicit substances, which is associated with an increased frequency of serious adverse outcomes. Before prescribing temazepam capsules and throughout treatment, assess each patient’s risk for abuse, misuse, and addiction (see WARNINGS).
- The continued use of benzodiazepines, including temazepam capsules, may lead to clinically significant physical dependence. The risks of dependence and withdrawal increase with longer treatment duration and higher daily dose. Abrupt discontinuation or rapid dosage reduction of temazepam capsules after continued use may precipitate acute withdrawal reactions, which can be life-threatening. To reduce the risk of withdrawal reactions, use a gradual taper to discontinue temazepam capsules or reduce the dosage (see DOSAGE AND ADMINISTRATION and WARNINGS).
Temazepam, USP is a benzodiazepine hypnotic agent. The chemical name is 7-chloro-1, 3-dihydro-3-hydroxy-1-methyl-5-phenyl-2H-1, 4-benzodiazepin-2-one, and the structural formula is:
C16 H13 ClN2 O2 MW = 300.7
Temazepam, USP is a white or almost white crystalline powder, freely slightly soluble in methanol and methylene chloride.
Temazepam Capsules USP, 7.5 mg, 15 mg, 22.5 mg, and 30 mg, are for oral administration.
7.5 mg, 15 mg, 22.5 mg, and 30 mg Capsules
Active Ingredient: temazepam USP
7.5 mg Capsules
Inactive Ingredients: lactose monohydrate, croscarmellose sodium, microcrystalline cellulose, sodium lauryl sulphate, magnesium stearate, FD&C Blue 1, D&C Red 28, FD&C Red 40, titanium dioxide, gelatin.
15 mg Capsules
Inactive Ingredients: lactose monohydrate, croscarmellose sodium, microcrystalline cellulose, sodium lauryl sulphate, magnesium stearate, FD&C Blue 1, FD&C Red 40, titanium dioxide, gelatin.
22.5 mg Capsules
Inactive Ingredients: lactose monohydrate, croscarmellose sodium, microcrystalline cellulose, sodium lauryl sulphate, magnesium stearate, FD&C Blue 1, D&C Red 28, titanium dioxide, gelatin.
30 mg Capsules
Inactive Ingredients: lactose monohydrate, croscarmellose sodium, microcrystalline cellulose, sodium lauryl sulphate, magnesium stearate, FD&C Blue 1, FD&C Red 40, D&C Red 28, gelatin, titanium dioxide.
The printing ink contains shellac, propylene glycol, potassium hydroxide and iron oxide black.
In a single and multiple dose absorption, distribution, metabolism, and excretion (ADME) study, using 3 H labeled drug, temazepam capsules was well absorbed and found to have minimal (8%) first pass metabolism. There were no active metabolites formed and the only significant metabolite present in blood was the O-conjugate. The unchanged drug was 96% bound to plasma proteins. The blood level decline of the parent drug was biphasic with the short half-life ranging from 0.4 to 0.6 hours and the terminal half-life from 3.5 to 18.4 hours (mean 8.8 hours), depending on the study population and method of determination. Metabolites were formed with a half-life of 10 hours and excreted with a half-life of approximately 2 hours. Thus, formation of the major metabolite is the rate limiting step in the biodisposition of temazepam. There is no accumulation of metabolites. A dose-proportional relationship has been established for the area under the plasma concentration/time curve over the 15 to 30 mg dose range.
Temazepam was completely metabolized through conjugation prior to excretion; 80% to 90% of the dose appeared in the urine. The major metabolite was the O-conjugate of temazepam (90%); the O-conjugate of N-desmethyl temazepam was a minor metabolite (7%).
Bioavailability, Induction, and Plasma Levels
Following ingestion of a 30 mg temazepam capsule, measurable plasma concentrations were achieved 10 to 20 minutes after dosing with peak plasma levels ranging from 666 to 982 ng/mL (mean 865 ng/mL) occurring approximately 1.2 to 1.6 hours (mean 1.5 hours) after dosing.
In a 7 day study, in which subjects were given a 30 mg temazepam capsule 1 hour before retiring, steady-state (as measured by the attainment of maximal trough concentrations) was achieved by the third dose. Mean plasma levels of temazepam (for days 2 to 7) were 260±210 ng/mL at 9 hours and 75±80 ng/mL at 24 hours after dosing. A slight trend toward declining 24 hour plasma levels was seen after day 4 in the study, however, the 24 hour plasma levels were quite variable.
At a dose of 30 mg once-a-day for 8 weeks, no evidence of enzyme induction was found in man.
Elimination Rate of Benzodiazepine Hypnotics and Profile of Common Untoward Effects
The type and duration of hypnotic effects and the profile of unwanted effects during administration of benzodiazepine hypnotics may be influenced by the biologic half-life of the administered drug and for some hypnotics, the half-life of any active metabolites formed. Benzodiazepine hypnotics have a spectrum of half-lives from short (<4 hours) to long (>20 hours). When half-lives are long, drug (and for some drugs their active metabolites) may accumulate during periods of nightly administration and be associated with impairments of cognitive and/or motor performance during waking hours; the possibility of interaction with other psychoactive drugs or alcohol will be enhanced. In contrast, if half-lives are shorter, drug (and, where appropriate, its active metabolites) will be cleared before the next dose is ingested, and carry-over effects related to excessive sedation or CNS depression should be minimal or absent. However, during nightly use for an extended period, pharmacodynamic tolerance or adaptation to some effects of benzodiazepine hypnotics may develop. If the drug has a short elimination half-life, it is possible that a relative deficiency of the drug, or, if appropriate, its active metabolites (i.e., in relationship to the receptor site) may occur at some point in the interval between each night’s use. This sequence of events may account for 2 clinical findings reported to occur after several weeks of nightly use of rapidly eliminated benzodiazepine hypnotics, namely, increased wakefulness during the last third of the night, and the appearance of increased signs of daytime anxiety.
Controlled Trials Supporting Efficacy
Temazepam capsules improved sleep parameters in clinical studies. Residual medication effects (“hangover”) were essentially absent. Early morning awakening, a particular problem in the geriatric patient, was significantly reduced.
Patients with chronic insomnia were evaluated in 2 week, placebo controlled sleep laboratory studies with temazepam capsules at doses of 7.5 mg, 15 mg, and 30 mg, given 30 minutes prior to bedtime. There was a linear dose-response improvement in total sleep time and sleep latency, with significant drug-placebo differences at 2 weeks occurring only for total sleep time at the 2 higher doses, and for sleep latency only at the highest dose.
In these sleep laboratory studies, REM sleep was essentially unchanged and slow wave sleep was decreased. No measurable effects on daytime alertness or performance occurred following temazepam capsules treatment or during the withdrawal period, even though a transient sleep disturbance in some sleep parameters was observed following withdrawal of the higher doses. There was no evidence of tolerance development in the sleep laboratory parameters when patients were given temazepam capsules nightly for at least 2 weeks.
In addition, normal subjects with transient insomnia associated with first night adaptation to the sleep laboratory were evaluated in 24 hour, placebo controlled sleep laboratory studies with temazepam capsules at doses of 7.5 mg, 15 mg, and 30 mg, given 30 minutes prior to bedtime. There was a linear dose-response improvement in total sleep time, sleep latency and number of awakenings, with significant drug-placebo differences occurring for sleep latency at all doses, for total sleep time at the 2 higher doses and for number of awakenings only at the 30 mg dose.
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