chlordiazepoxide
n. the first commercially available benzodiazepine anxiolytic. Developed in 1957 and in clinical use in the early 1960s, it became one of the most heavily prescribed medications ever developed. It is characterized by extensive metabolism in the liver and possesses a number of metabolic products, giving it a lengthy half-life and a consequent long-acting anxiolytic effect. Its use in the management of anxiety and insomnia has been largely supplanted by benzodiazepines with less complicated metabolism and more predictable half-lives, but it remains in common use to protect against the effects of alcohol withdrawal. It is available in oral and injectable form. Because of erratic absorption, intramuscular administration is not advised. U.S. trade name: Librium.