Alprazolam is a triazolobenzodiazepine, a derivative of the benzodiazepines. Comparison studies of alprazolam and diazepam or chlordiazepoxide in patients suffering from clinical anxiety secondary to anxiety neurosis or chronic alcohol withdrawal suggest an equal efficacy of those agents. Studies examining the use of alprazolam for the treatment of "primary depression" suggest that it is as effective as imipramine in the treatment of exogenous (reactive) depression. Although alprazolam may be effective in patients with exogenous depression, no extrapolation can be made to the treatment of endogenous depression. Mechanisms of action have not been fully elucidated, but probably are similar to those of other benzodiazepines. Peak blood levels are reached in 0.7-1.6 hours and the elimination half-life after steady state is approximately 19 hours. Daily dosages established from clinical studies ranged from 1 to 6 mg. Clinically, alprazolam appears to be ten times more potent than diazepam. Drowsiness, headaches, lightheadedness, dry mouth, and depression appear to be the most common side effects of the drug. It is concluded that alprazolam offers no striking therapeutic advantage over currently marketed benzodiazepines.