Clinical neuropharmacology of sleep disorders

Within the context of the comprehensive treatment of sleep disorders, which includes medical, neurologic, psychiatric, and social interventions, use of medication is often indicated. Among the three benzodiazepine hypnotics that are available in the United States for the treatment of insomnia, flurazepam is effective for both sleep induction and maintenance, and it retains most of its efficacy over a 4-week period of nightly administration; temazepam is effective only for sleep maintenance, and triazolam improves both sleep induction and maintenance with initial but not with continued administration. Rebound phenomena are more frequent and intense with the more rapidly eliminated drug, triazolam, and to a lesser degree with temazepam. Also, with triazolam, certain behavioral side effects, such as amnesia and psychotic-like symptoms, have been reported. With flurazepam, which is a slowly eliminated benzodiazepine, daytime sedation is more frequent than with the other two drugs. When insomnia is secondary to major depression, antidepressant medication should be administered. Methylphenidate, amphetamines, or other stimulant medications are used for the symptomatic treatment of the sleepiness and sleep attacks of narcolepsy and hypersomnia. For cataplexy and the other two auxiliary symptoms of narcolepsy, imipramine or other tricyclics are the drugs of choice. Protriptyline and medroxyprogesterone have been used in treating mild cases of obstructive sleep apnea, but their efficacy is limited. Similarly, for the treatment of central sleep apnea, medroxyprogesterone and acetazolamide have shown only limited effects. Medication for patients with sleepwalking, night terrors, or nightmares should be prescribed judiciously, and primarily when treatment of an underlying psychiatric condition is desired. The neuropharmacology of sleep should also consider drugs that may cause sleep disorders. Medications with sleep disturbing effects include various antihypertensives, bronchodilators, and the energizing antidepressants. Withdrawal of REM-suppressant drugs, such as the barbiturates, may cause nightmares in association with a REM rebound. Occasionally, a drug or a combination of drugs may produce somnambulistic-like activity in some patients.