[Smoking cessation and drug interactions].

Tobacco smoke can cause drug interactions by induction of CYP1A2, which metabolizes drugs like clozapine, olanzapine and theophylline. This means that smokers need higher doses to achieve the same plasma concentrations as non-smokers. Furthermore, smoking cessation can cause an increase in plasma concentrations of drugs metabolised by CYP1A2, which in turn may lead to adverse effects. Of the drugs used for smoking cessation only bupropione has clinically relevant interactions. All of these situations may be handled by dose adjustment.