Smoking cigarettes can alter the way individuals respond to various medications. Cigarette smoke contains hydrocarbons that can induce enzymes in the liver to make some drugs less effective.

Smoking may reduce the effect of the following medications...and therefore a reduced dose may be required after smoking cessation:

Analgesics: Smoking may reduce the effect of pain medications such as pentazocine (e.g.,Talwin) and propoxyphene (e.g.,Darvon).

Antianxiety Agents: Smoking may reduce the effect of chlordiazepoxide (e.g.,Librium) and diazepam (e.g.,Valium).

Antidepressants: Smoking may reduce the effect of tricyclic antidepressants such as imipramine, amitriptyline, desipramine, and nortriptyline.

Antipsychotics: Smoking may reduce the effect of chlorpromazine, clozapine, and olanzapine.

Propranolol: Smoking may inhibit the effect of propranolol (e.g.,Inderal). This is especially important if the propranolol is being used to reduce angina pectoris.

Theophylline: Smoking may reduce the effect of this anti-asthmatic drug.

Heparin: Smoking may reduce the effect of this anticoagulant drug. The response to oral anticoagulant drugs such as warfarin does not appear to be affected by smoking.

Insulin: Nicotine suppresses insulin out from the pancreas.