Insomnia: drug treatment.

This is a review and update on hypnotics. Insomnia is a symptom of many underlying conditions which have to be evaluated before resorting to medication. Hypnotics are useful for short term treatment. The benzodiazepines have replaced the barbiturates which have a low therapeutic index. The action of benzodiazepines depends on their absorption rate, lipophilicity, half-life and metabolites. They induce sleep, prolonged sleep time and reduced night wakenings. They increase stage 2 sleep, and reduce stage 1, 3, 4 and REM (Rapid Eye Movement) sleep. Flurazepam, triazolam and midaolam are described. The benzodiazepines suffer from many unwanted effects which include tolerance, dependence, withdrawal symptoms, rebound insomnia, hang over effect, alteration of memory process and synergism with ethanol. The ideal hypnotic should be free from these drawbacks. Three new generation hypnotics quazepam, zopiclone and zolpidem are described. Drugs suitable for long term hypnotic medication include antipsychotics, antidepressants and antihistamines.