What are the clinically significant drug interactions with cigarette smoking?

This Medicines Q&A summarises drug interactions with cigarette smoking that are considered to be most clinically important.

  • Most interactions between drugs and smoking are not clinically significant.
  • Healthcare professionals giving smoking cessation advice should be aware of a small number of medicines, in particular aminophylline, theophylline, clozapine, olanzapine, erlotinib and riociguat, which may require dose adjustment or increased monitoring when smoking status is altered.
  • Patients taking narrow-therapeutic-index drugs should be monitored closely when any lifestyle modification is made.
AminophyllineChlorpromazineClozapineDrug interactionsErlotinibMedicineMethadoneOlanzapineQ&ARiociguatTheophyllineWarfarin