Rebound insomnia

Rebound insomnia and hypnotic self administration

Twenty-one (three groups of seven), men and women, 25-50 years of age were studied to determine whether or not rebound insomnia would increase the likelihood of self administering a benzodiazepine (triazolam 0.25 mg) hypnotic. The groups compared were patients with insomnia and disturbed sleep, insomnia and normal sleep, and healthy normals. Rebound insomnia, by both subjective and polysomnographic assessment, was induced. The experience of rebound insomnia did not increase the likelihood of self administering a benzodiazepine hypnotic in any of the groups. There were clear group differences in pill self administration with normals rarely and insomnia patients frequently, but not differentially (placebo versus active drug) self administering pills.

Disinhibitory reactions to benzodiazepines: a review

This article reviews some of the important aspects of benzodiazepine-induced disinhibitory reactions. Although reactions of this type are relatively rare, they may sometimes manifest themselves in aggressive behavior accompanied by suicidal or homicidal tendencies. It appears that these reactions occur more commonly in younger patients, although the elderly (above 65 years) may also be at risk. Many mechanisms have been postulated, but none truly explain how these reactions arise. The concept that central cholinergic mechanisms may play a role, however, remains attractive and stems primarily from physostigmine's ability to successfully reverse this type of reaction. The potential role of the benzodiazepine antagonists, eg, flumazenil, in reversing disinhibitory reactions is also discussed. Apart from patients who previously exhibited poor impulse control, there are no reliable indicators for recognizing potential candidates for this type of reaction. To minimize the occurrence of disinhibitory reactions, some guidelines, which include the avoidance of certain drug combinations, the use of low doses of benzodiazepines, slow incremental intravenous administration, and good rapport with patients, are presented.

Role of hypnotic drugs in general practice

General practice physicians commonly deal with patients who report experiencing insomnia. Advances in our understanding of insomnia should result in much more effective diagnosis and therapeutic intervention for insomnia patients at the primary care level. This presentation highlights the new knowledge of insomnia pertinent to general practice physicians and discusses the rational use of hypnotic medications in primary care.

Rebound insomnia: its determinants and significance

Rebound insomnia is a sleep disturbance that occurs on discontinuation of benzodiazepine hypnotic drugs. It has been reported in both patients and healthy normal subjects and is characterized by increased wakefulness above the person's baseline levels. This article reviews that available information regarding determinants, possible mechanisms, and clinical significance of rebound insomnia. It is concluded that rebound insomnia is a disturbance of one or two nights' duration that primarily follows discontinuation of short- to intermediate-acting benzodiazepines. It occurs at high doses of a given drug, beyond which no additional hypnotic efficacy is evident. There seem to be clear individual differences in the experience of rebound insomnia, but no prospective studies have established which differences predict rebound. It is likely to be avoided by initiating treatment with the lowest effective dose and tapering the dose upon discontinuation.

Dose determinants of rebound insomnia

A polysomnographic assessment in healthy normal sleepers of possible dose relations for rebound insomnia was conducted. As an additional measure of rebound the study included a direct test of sleep/wake tendency during the night of drug discontinuation. Twelve, healthy men (21-30 years) each received placebo, 0.25 mg and 0.50 mg triazolam for 6 consecutive nights followed by a discontinuation night and 14 nights of recovery at home. The three conditions were presented, double-blind, in a latin square design. On night 6 of drug administration both doses increased total sleep time compared to placebo, but 0.50 mg did not improve sleep beyond 0.25 mg. On drug discontinuation (night 7) wake time over the 8 h recording and sleep latency after an experimental awakening (02.30 h) were increased with 0.50 mg compared to placebo and 0.25 mg. On these measures of rebound 0.25 mg did not differ from placebo. Thus rebound insomnia occurred only at a dose (0.50 mg) which produced no additional hypnotic efficacy in these normal sleepers. Whether tests of sleep/wake tendency make a useful measure of rebound insomnia needs further clarification.

New drug evaluations. Triazolam

Triazolam is a sedative/hypnotic triazolobenzodiazepine, structurally related to alprazolam. Recently, it has been approved for the short-term management of insomnia characterized by difficulty in falling asleep, frequent nocturnal awakenings, and/or early morning awakenings. Triazolam is metabolized with a half-life of 1.5-5.0 hours. Its one active metabolite, which appears in low concentrations and is inactivated rapidly, is not thought to contribute to its pharmacologic activity. Triazolam has been shown to decrease sleep latency and the number of nocturnal awakenings while increasing total sleep time in patients with insomnia. Sleep electroencephalogram studies show that triazolam has no effect on delta-sleep (Stages 3 and 4) and has variable effects on rapid-eye-movement sleep. Nighttime administration of triazolam increases daytime alertness in insomniacs and improves or has no effect on performance. The reported side effects are similar to those of other benzodiazepines and include drowsiness, dizziness, and dry mouth. The recommended dosage of triazolam is 0.25-0.5 mg hs. A reduced initial dose of 0.125 mg should be used in geriatric patients.

Pharmacology and hypnotic efficacy of triazolam

Triazolam is a new triazolobenzodiazepine drug that is indicated for the treatment of insomnia. The usual adult dosage is 0.25 to 0.5 mg; for geriatric patients a dose of 0.125 to 0.25 mg is recommended. Triazolam is readily absorbed and quickly eliminated with a half-life of 2-5 hours, making it the shortest acting benzodiazepine available in the United States. Sleep laboratory and non-laboratory clinical trials found triazolam 0.25 and 0.5 mg effective in inducing and maintaining sleep. It remained effective in laboratory studies of up to one month duration and non-laboratory studies of up to six months duration when the drug was administered nightly. On discontinuation disturbed sleep for one or two nights was observed in some studies. Triazolam impairs performance for several hours after administration. However, unlike benzodiazepines with long-acting metabolites, triazolam is relatively free of daytime residual effects, which is attributable to its short half-life. Overall, triazolam is an effective and safe compound for the symptomatic treatment of insomnia complaints.

[Benzodiazepines: significance of kinetics for therapy]

The onset and duration of action of benzodiazepines after single oral doses depend largely on absorption rate and the rate and extent of distribution. The rate and extent of accumulation during multiple dosage depend on elimination half-life and clearance. A framework is proposed for classification of benzodiazepines according to elimination half-life. Long acting benzodiazepines have half-life values usually exceeding 24 h. Drugs in this category have long-acting pharmacologically active metabolites, often desmethyldiazepam, accumulate extensively during multiple dosage, and may have impaired clearance in the elderly and those with liver disease. Intermediate and short-acting benzodiazepines have half-life values from 5-24 h and active metabolites are uncommon. Accumulation during multiple dosage is less extensive than with the long-acting group and diminishes as the half-life becomes shorter. Age and liver disease have a small influence on metabolic clearance. The half-life of ultrashort-acting benzodiazepines is less than 5 h. These drugs are essentially nonaccumulating. Pharmacokinetic classification may assist in understanding differences among benzodiazepines, but does not explain all of their clinical actions.