Specialist Pharmacy Service: What are the clinically significant drug interactions with tobacco smoking?
Most interactions between drugs and tobacco smoking are not clinically significant.
When giving smoking cessation advice, be aware of a small number of drugs, in particular aminophylline, theophylline, clozapine, erlotinib, olanzapine, riociguat, chlorpromazine, flecainide, methadone, and warfarin which may require dose adjustment or increased monitoring when smoking status is altered.
Close monitoring of plasma levels (where useful), clinical progress and adverse effect occurrence and severity is essential when patients change their smoking status.
If the affected drug is prescribed under the supervision of a specialist, their input should be sought if the patient changes their smoking status.
