Clinical Depression of the Central Nervous System Due to Diazepam and Chlordiazepoxide in Relation to Cigarette Smoking and Age

Abstract

Frequencies of clinical depression of the central nervous system (CNS), as indicated by drowsiness attributable to drugs were compared among nonsmokers, light smokers (20 cigarettes per day or less), and heavy smokers who received diazepam, chlordiazepoxide, or phenobarbital for anxiety. With the two benzodiazepines, CNS depression was less common the greater the number of cigarettes smoked. This trend was not evident with phenobarbital. CNS depression attributed to the benzodiazepines became more common with increasing age. The age trend was also not evident in patients who received phenobarbital. Increased benzodiazepine metabolism in cigarette smokers and decreased metabolism in older patients may explain these findings.