Hypnotics: rebound insomnia and residual sequelae

A practical guide to prescribing in nursing homes. Avoiding the pitfalls

The abundant use of drugs in nursing homes demands special attention. Inappropriate indications and dosages, and lack of monitoring of drug-related effects and adverse reactions in patients are problems which can easily be solved. Knowledge of basic aspects of geriatric pharmacokinetics, and of basic rules and the main pitfalls involved in prescribing drugs for the elderly is essential, and demands both training of personnel and a change in prevailing attitudes.

Guidelines for the rational use of benzodiazepines. When and what to use

The main actions of benzodiazepines (hypnotic, anxiolytic, anticonvulsant, myorelaxant and amnesic) confer a therapeutic value in a wide range of conditions. Rational use requires consideration of the large differences in potency and elimination rates between different benzodiazepines, as well as the requirements of individual patients. As hypnotics, benzodiazepines are mainly indicated for transient or short term insomnia, for which prescriptions should if possible be limited to a few days, occasional or intermittent use, or courses not exceeding 2 weeks. Temazepam, loprazolam and lormetazepam, which have a medium duration of action are suitable. Diazepam is also effective in single or intermittent dosage. Potent, short-acting benzodiazepines such as triazolam appear to carry greater risks of adverse effects. As anxiolytics, benzodiazepines should generally be used in conjunction with other measures (psychological treatments, antidepressants, other drugs) although such measures have a slower onset of action. Indications for benzodiazepines include acute stress reactions, episodic anxiety, fluctuations in generalised anxiety, and as initial treatment for severe panic and agoraphobia. Diazepam is usually the drug of choice, given in single doses, very short (1 to 7 days) or short (2 to 4 weeks) courses, and only rarely for longer term treatment. Alprazolam has been widely used, particularly in the US, but is not recommended in the UK, especially for long term use. Benzodiazepines also have uses in epilepsy (diazepam, clonazepam, clobazam), anaesthesia (midazolam), some motor disorders and occasionally in acute psychoses. The major clinical advantages of benzodiazepines are high efficacy, rapid onset of action and low toxicity. Adverse effects include psychomotor impairment, especially in the elderly, and occasionally paradoxical excitement. With long term use, tolerance, dependence and withdrawal effects can become major disadvantages. Unwanted effects can largely be prevented by keeping dosages minimal and courses short (ideally 4 weeks maximum), and by careful patient selection. Long term prescription is occasionally required for certain patients.

Substituting behavioural treatment for drugs in the treatment of insomnia: an exploratory study

There is need to investigate directly the generalizability of psychological treatment effects to clinical populations of insomniacs; especially to those who are chronic hypnotic users and are drug-dependent. This paper present two methodological models, based upon the pharmacological literature, which permit the selection of such subjects for research studies. The usefulness of the models is discussed with reference to a preliminary investigation based on 10 cases, and recommendations are made both for further research and clinical practice.

The clinical use of hypnotics: indications for use and the need for a variety of hypnotics

Insomnia may be categorized as difficulty falling asleep, frequent awakening, early awakenings or a combination of each. The ideal hypnotic must promote rapid sleep onset and maintain sleep throughout the night while allowing the patient to awake refreshed the following day. Several benzodiazepines, with differing pharmacokinetic and pharmacodynamic profiles are presently available. All are clinically effective and not only elimination half-life but also dosage prescribed and pattern of distribution are important factors for determining treatment response. Hypnotics have been divided into those with long elimination half-lives (e.g. nitrazepam, flunitrazepam, flurazepam), those with intermediately long half-lives (brotizolam, loprazolam, lormetazepam, temazepam) and those with short half-lives (midazolam and triazolam). Carry-over effects into the morning such as excessive daytime sleepiness or drowsiness are related to drug half-life, dosage and pattern of distribution. In equipotent dosages most controlled clinical trials have found no significant differences between the various benzodiazepine hypnotics. Nevertheless, clinicians in general tend to use long half-life benzodiazepines in patients who have difficulties maintaining sleep and short half-life benzodiazepines for treating sleep onset insomnia. Intermediately long half-life, benzodiazepines are used for both indications and most clinicians feel that the choice of hypnotic should not only be influenced by elimination half-life or the dosage used, but by individual patient preference. Hypnotics should be used for only short periods of time and in those patients for whom a more chronic use is indicated, they should be used only on an intermittent basis.

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.

Pharmacological effects of sedative-hypnotics, narcotic analgesics, and alcohol during sleep

This article briefly reviews the well known effects of sedative-hypnotics, alcohol and narcotics on sleep. These drugs also have respiratory depressant effects, and the limited information about their effects on sleep-related breathing disturbances is reviewed. They exacerbate obstructive sleep apnea syndrome and have moderate to minimal effects on occasional apnea or hypopnea, but do not induce breathing disturbances de novo.

The acceptability of a non-benzodiazepine hypnotic (Zopiclone) in general practice

The hypnotic effects of Zopiclone, a novel cyclopyrrolone derivative, were compared with placebo in a double-blind randomized crossover study in insomniac patients. Subjective morning assessments by the patients showed that Zopiclone 7.5 mg improved the quality of sleep, with a reduction in the sleep onset latency and the number of nocturnal awakenings. Zopiclone was judged by the physicians to be superior to placebo and was preferred by the patients. Subjective residual effects and adverse reactions were minimal.

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.

[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.

Sleep laboratory study of the effects of midazolam in insomniac patients

The effects of midazolam, a short-acting imidazobenzodiazepine, on the sleep cycle of insomniac patients were assessed by means of polygraphic recordings. Baseline placebo nights were compared with drug (30 mg p.o.) and placebo withdrawal nights. The compound was effective in inducing and maintaining sleep on short- and intermediate-term administration. Tolerance was not observed following two weeks of drug use. Subjective reports corroborated the effectiveness of midazolam as a hypnotic. In regard to its effects on sleep stages, midazolam markedly decreased Stage 3 and abolished Stage 4 sleep, while Stage 2 was augmented. REM sleep percentage was not significantly affected. Withdrawal of midazolam was followed by rebound insomnia, in which sleep latency, total wake time and wake time after sleep onset were increased above baseline. Side-effects related to midazolam administration included headache, muscular weakness and dizziness. They were mild and wore off 1-2 hours after awakening.

Triazolam: a review of its pharmacological properties and therapeutic efficacy in patients with insomnia

Triazolam is a triazolobenzodiazepine with hypnotic properties, advocated for use in acute or chronic insomnia, situational insomnia in hospitalised patients, and insomnia associated with other disease states. As triazolam has a relatively short half-life of about 2 to 3 hours in healthy subjects and has only 1 short acting active metabolite, alpha-hydroxytriazolam, it would seem more suitable as an hypnotic than longer acting drugs such as flurazepam, nitrazepam or flunitrazepam, particularly when residual sedative effects on the day after ingestion are undesirable. Thus, with usual hypnotic doses of triazolam (0.25 or 0.5 mg) impairment of psychomotor and cognitive function is generally not carried over into the day after ingestion, although at doses of 1 mg or greater, residual effects may appear. In short term comparative studies triazolam was clearly superior to a placebo, and was at lest as effective as flurazepam, or other benzodiazepines such as nitrazepam or diazepam, in hastening sleep onset, reducing nocturnal awakenings, and increasing sleep duration. In other studies it was often superior to chloral hydrate, methyprylone or quinalbarbitone (secobarbital). In a small number of patients with chronic insomnia receiving extended treatment with triazolam in a clinical setting or in some sleep laboratory studies, no evidence of tolerance occurred; however, some evidence of reduced effect with repeated administration has been reported in one sleep laboratory study. Thus, a definitive statement about the likelihood of tolerance occurring on repeated administration is difficult to make at this time.

Evaluation of temazepam as a hypnotic

Temazepam is a 1,4-benzodiazepine, newly marketed in the United States for the symptomatic treatment of the complaint of insomnia. The manufacturer recommends a dose of 30 mg before bedtime for most adults and 15 mg for geriatric or debilitated patients. A dose of 30 mg usually produces peak plasma concentrations within 3 hours after oral ingestion and has a mean half-life of 10 to 15 hours. Thus, temazepam is absorbed more slowly and metabolized more quickly than flurazepam, the only other benzodiazepine marketed in the United States specifically for insomnia. Eight sleep laboratory and 21 clinical studies on temazepam indicate that temazepam reduces awakening during the night and increases sleep duration. However, there was no consistent evidence that temazepam reduces sleep latency--probably because temazepam, taken at bedtime, does not reach sufficiently high blood levels in time to affect sleep onset. One sleep laboratory study on 8 insomniac patients given 35 consecutive nightly doses of 30 mg found no evidence of tolerance or rebound insomnia. Studies on tolerance, metabolism and carry-over effects have shown that temazepam has no long-acting metabolites and does not affect waking function following use at bedtime. In patients for whom hypnotic medication is appropriate, temazepam should be an effective drug for reducing most symptoms of insomnia.

Temazepam: a review of its pharmacological properties and therapeutic efficacy as an hypnotic

Temazepam is a benzodiazepine drug which is a minor metabolite of diazepam. In clinical studies using subjective evaluation methods it was effective for maintaining sleep and increasing total sleep time. However, sleep laboratory studies did not show a significant effect on some sleep parameters, especially sleep induction. Temazepam has a relatively short half-life (about 5 to 11 hours, longer in some subjects and in the elderly), and no active metabolites of clinical importance, and thus may be considered more suitable for use as an hypnotic than longer acting drugs such as diazepam, nitrazepam or flurazepam when residual sedative effects the next day are not desirable. Indeed, few residual effects on morning performance appear to occur with usual single doses of temazepam, although at the upper end of the recommended dosage range (30 mg or more) some evidence of impaired psychomoter and cognitive function in the morning has been reported. Whether or not temazepam is likely to produce "hangover" with repeated night-time administration needs further clarification. While a call for a large number of controlled trials may not be justifiable in evaluating a new hypnotic, a few well designed additional comparative studies in insomniac subjects are needed to assess adequately the relative merits of temazepam (particularly with regard to sleep onset) compared with other benzodiazepine hypnotics, especially those which are short- or intermediate-acting.

The use of short- and long-acting hypnotics in clinical medicine

1 Activity of short- and long-acting benzodiazepines is reviewed with reference to pharmacokinetics and residual sequelae, and to efficacy and adverse effects. 2 Some benzodiazepines may not lead to obvious effects on performance, such as nordiazepam and clobazam, and the persistence of residual sequelae may not relate obviously to elimination half-lives (as with diazepam and possibly flunitrazepam). However, benzodiazepines with mean half-lives less than 8 h may have residual sequelae, whereas hypnotics with mean half-lives greater than 16 h are likely to lead to impared performance and/or anxiolytic effects the next day. 3 Potassium chlorazepate 15 mg, with its long-acting metabolite nordiazepam, would seem to be the drug of choice for insomnia secondary to anxiety. For the insomniac without significant psychopathology, temazepam 10-20 mg, triazolam 0.125-0.25 mg and for occasional use, diazepam 5-10 mg, provide the initial approach. Flurazepam hydrochloride 15-30 mg, nitrazepam 5-10 mg and flunitrazepam 1 mg and above, have persistent residual effects and should be reserved for refractory patients, and for those in whom some impairment of performance the next day would be acceptable. 4 There is little or no evidence to suggest that the proper use of the short-acting hypnotics, triazolam and temazepam, leads to a worsening of sleep on withdrawal. However, some benzodiazepines may lead to disturbances of sleep and/or rebound insomnia, and nitrazepam and flunitrazepam may be implicated.

Evaluation of single-dose hypnotic treatment before elective operation

A prospective randomised double-blind controlled trial was carried out to evaluate the place of a single dose of triazolam, flurazepam, and placebo on the evening before an elective operation in 96 patients. Features of sleep were recorded by patients and nurses on questionnaires. Onset of sleep was delayed and duration of sleep reduced in two-thirds of patients allocated placebo compared with their normal sleep pattern. Two-thirds of these patients also complained of waking more than twice during the night. Both hypnotics significantly improved the duration and time of onset of sleep and reduced the frequency of wakening when compared with the placebo. Patients who took triazolam, however, fell asleep faster and woke less often than those who took flurazepam. Furthermore, triazolam appeared to have advantages over flurazepam before surgery. Thus giving a single dose of a hypnotic on the night before an elective operation improves the patient's sleep, and greater benefit was derived from triazolam than flurazepam.