antianxiety drug, drug administered for the relief of anxiety. Although their action is not fully understood, most antianxiety medications appear to affect the action of neurotransmitters in the brain (see serotonin and norepinephrine). They may work by affecting the limbic system, that part of the brain associated with emotion.
Antianxiety drugs frequently prescribed in the United States include the benzodiazepines alprazolam (Xanax) and clonazepam (Clonopin), most often prescribed for panic attacks and general anxiety. Long-term use is discouraged because of side effects (impaired alertness, sedation, interactions with alcohol and other drugs), potential for addiction, and withdrawal symptoms. Nonbenzodiazepine drugs that work by acting on benzodiazepine receptors include zolpidem (Ambien), which is widely prescribed as a sleeping pill. Beta-blockers, usually prescribed for hypertension, are sometimes used for people facing an anxiety-producing "crisis," such as performing on the stage or giving a speech. Buspirone (BuSpar), a drug chemically unrelated to the benzodiazepines or beta-blockers, is often preferred for cases of long-term anxiety because it has fewer side effects, less addictive potential, and no withdrawal symptoms.