No Effect of Smoking on Metabolism of Chlordiazepoxide

To the Editor: The incidence of excessive sedation after chronic dosing of chlordiazepoxide (Librium) is smaller in tobacco smokers than in nonsmokers.¹ This difference may be due to an increase in metabolic (systemic) clearance of the drug caused by enzyme inducers present in tobacco smoke, or an alteration in brain sensitivity, or both. To investigate pharmacokinetic differences, we have studied the disposition of chlordiazepoxide after a single, rapid intravenous injection (as hydrochloride, 0.6 mg per kilogram of body weight) in 28 nonsmokers (17 male and 11 female) and 17 smokers (nine male and eight female). Since the disposition of chlordiazepoxide. No extract is available for articles shorter than 400 words.