Tranquilizer
Tranquilizer, common name applied to a class of drugs used to treat anxiety and insomnia. Originally the term comprised two groups: the major tranquilizers—the phenothiazines, such as chlorpromazine (Thorazine)—useful in the treatment of acutely ill mental patients (see Mental Illness ); and the minor tranquilizers—the benzodiazepines, such as diazepam (Valium). The minor tranquilizers are safe when taken alone, but taking substantial amounts of these substances at the same time as alcohol can lead to coma or even death. Long-term administration of larger than usual doses of the benzodiazepines can cause physical dependence, with typical withdrawal symptoms ranging from nightmares to convulsions when the drug intake is stopped.