Tobacco smoking and drugs: a clinically important interaction?

Tobacco smoking may interact with the metabolism of a number of drugs. This has been demonstrated clearly in pharmacokinetic studies in animals and man. HOwever, tobacco smoking as a variant has been studied with relatively few clinically essential drugs and these studies do not always demonstrate a consistent effect of smoking. This review therefore not only records what data have emerged from pharmacokinetic or other studies, but it also attempts to determine whether such interactions have clinical significance. The main finding of this review is that, in the majority of examples, there is little evidence that there is a recognizable hazard from the interaction per se. The exceptions to this general conclusion are limited to four drugs: insulin, propoxyphene, propranolol, and theophylline preparations. With these drugs, there is some evidence of clinical importance of an interaction with tobacco smoking.