Temazepam

UNDER REVIEW (September 2016)

Mechanism of Action:

Temazepam is a benzodiazepine that binds to specific benzodiazepine-receptors, which are part of the GABA-receptors. On binding it causes an increase in the inhibitory effects on GABA.

Lecture and CAL materials:


Drug specifics

Alternative drug name not specified
Effects Hypnotics like temazepam should only be considered if the the cause of the insomnia has been established and, where possible, underlying factors have been treated. Some patients have unrealistic sleep expectations, and others understate their alcohol consumption which is often the cause of the insomnia. Transient insomnia may occur in those who normally sleep well and may be due to extraneous factors such as noise, shift work, and jet lag. If a hypnotic is indicated one that is rapidly eliminated should be chosen, and only one or two doses should be given. Short-term insomnia is usually related to an emotional problem or serious medical illness. It may last for a few weeks and may recur; a hypnotic can be useful but should not be given for more than three weeks (preferably only one week). Intermittent use is desirable with omission of some doses. A rapidly eliminated drug is generally appropriate. Chronic insomnia is rarely benefited by hypnotics and is more often due to mild dependence caused by injudicious prescribing. Psychiatric disorders such as anxiety, depression, and abuse of drugs and alcohol are common causes. Sleep disturbance is very common in depressive illness and early wakening is often a useful pointer. The underlying psychiatric complaint should be treated, adapting the drug regimen to alleviate insomnia. For example, amitriptyline and mirtazapine prescribed for depression, will also help to promote sleep if taken at night. Other causes of insomnia include daytime cat-napping and physical causes such as pain, pruritus, and dyspnoea. Hypnotics should not be prescribed indiscriminately and routine prescribing is undesirable. They should be reserved for short courses in the acutely distressed. Tolerance to their effects develops within 3 to 14 days of continuous use and long-term efficacy cannot be assured. A major drawback of long-term use is that withdrawal causes rebound insomnia and precipitates a withdrawal syndrome. Where prolonged administration is unavoidable hypnotics should be discontinued as soon as feasible and the patient warned that sleep may be disturbed for a few days before normal rhythm is re-established; broken sleep with vivid dreams and increased REM (rapid eye movement) sleep may persist for several weeks. The prescribing of hypnotics to children, except for occasional use such as for night terrors and somnambulism (sleep-walking), is not justified. Hypnotics should be avoided in the elderly, who are at risk of becoming ataxic and confused and so liable to fall and injure themselves.
Adverse actions Side-effects from temazepam are predictable and include drowsiness and lightheadedness the next day; confusion and ataxia (especially in the elderly); amnesia may occur; dependence.
Dose A 10mg tablet at night.
Interactions Like all benzodiazepines there is the potential for additive effects with other CNS depressants including alcohol.
Contraindications not specified
Comments OTHER HYPNOTIC DRUGS. Other benzodiazepines such as nitrazepam which is rather longer acting and has a greater risk of carryover effects. Zaleplon, zolpidem and zopiclone are non-benzodiazepine hypnotics, but they act at the benzodiazepine receptor. Zolpidem and zopiclone have a short duration of action; zaleplon is very short acting. All three drugs are not licensed for long-term use; dependence has been reported in a small number of patients. Chloral hydrate and derivatives were formerly popular hypnotics for children (but the use of hypnotics in children is not usually justified). There is no convincing evidence that they are particularly useful in the elderly and their role as hypnotics is now very limited. Triclofos causes fewer gastro-intestinal disturbances than chloral hydrate. Clomethiazole (chlormethiazole) may be a useful hypnotic for elderly patients because of its freedom from hangover but, as with all hypnotics, routine administration is undesirable and dependence occurs. It is licensed for use as a hypnotic only in the elderly (and for very short-term use in younger adults to attenuate alcohol withdrawal symptoms. Some antihistamines such as diphenhydramine and promethazine are on sale to the public for occasional insomnia; their prolonged duration of action may often lead to drowsiness the following day. The sedative effect of antihistamines may diminish after a few days of continued treatment; antihistamines are associated with headache, psychomotor impairment and antimuscarinic effects. Promethazine is also popular for use in children, but the use of hypnotics in children is not usually justified. Alcohol is a poor hypnotic because its diuretic action interferes with sleep during the latter part of the night. With chronic use, alcohol disturbs sleep patterns and causes insomnia.
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