bĕnˌzōdīăzˈəpēnˌ, any of a class of drugs prescribed for their tranquilizing, antianxiety, sedative, and muscle-relaxing effects. Benzodiazepines are also prescribed for epilepsy and alcohol withdrawal. Introduced in the early 1960s with chlordiazepoxide (Librium), benzodiazepines were heralded as a safer alternative to barbiturates and meprobamate because they were relatively non–habit forming and were less lethal in overdose.

There has been considerable debate over their side effects, addictiveness, and abuse, beginning with negative media attention given to diazepam (Valium) in the late 1960s and continuing with debate over triazolam (Halcion), which culminated in its withdrawal from the market in Britain and several other countries. All benzodiazepines appear to have amnesic side effects. Triazolam has been associated with depression, increased daytime anxiety in poor sleepers, and some cases of psychosis. Physical dependence on benzodiazepines is seen predominantly in patients who have taken the medications over long periods. Upon withdrawal the original symptoms often recur, and patients may experience anxiety, insomnia, perceptual changes, hallucinations, and seizures. These symptoms can be lessened by slowly tapering off the dose.

Abuse of benzodiazepines occurs most often in young white males who also abuse other substances. In this group benzodiazepines, especially diazepam and alprazolam (Xanax), are used, sometimes nasally, to ameliorate the unwanted effects of street drugs, such as cocaine. Flunitrazepam (Rohypnol), a prescription benzodiazepine sedative not approved in the United States, is increasingly being abused by teen-agers in some areas of the country. While many doctors feel benzodiazepines are safe and effective, especially for short-term relief of anxiety and insomnia, others feel that they mask underlying problems and invite dependence. There are 12 benzodiazepines now on the market, including clonazepam (Clonopin) and temazepam (Restoril).

See also antianxiety drug.

The Columbia Encyclopedia, Sixth Edition Copyright© 2004, Columbia University Press. Licensed from Lernout & Hauspie Speech Products N.V. All rights reserved.

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