tobacco
6 interactions related to tobacco
smoking + clozapine
Polycyclic aromatic hydrocarbons in tobacco smoke (not nicotine) potently induce CYP1A2, the enzyme responsible for roughly 70% of clozapine metabolism, lowering clozapine plasma levels by up to 50% in smokers. Sudden smoking cessation can cause clozapine levels to rise 50-72% within 3-5 days, risking sedation, seizures, and toxicity.
smoking + olanzapine
Polycyclic aromatic hydrocarbons in cigarette smoke induce CYP1A2, the primary enzyme that metabolizes olanzapine, increasing olanzapine clearance by roughly 37-48% in smokers. Meta-analysis data suggest olanzapine doses should be 30% lower in non-smokers than in smokers to reach the same plasma levels.
smoking + theophylline
Polycyclic aromatic hydrocarbons in tobacco smoke induce CYP1A2, increasing theophylline clearance by 58-100% and shortening its half-life by roughly 63%. Smokers often need 1.5-2 times the usual theophylline dose, and abrupt cessation can rapidly produce toxic levels.
smoking + propranolol
Cigarette smoking induces hepatic metabolism of propranolol via CYP1A2 and accelerated glucuronidation, increasing apparent oral clearance and reducing propranolol plasma concentrations in smokers compared with non-smokers. Nicotine also independently raises heart rate, blood pressure, and circulating catecholamines, partially counteracting propranolol's beta-blocking effect.
smoking + caffeine
Polycyclic aromatic hydrocarbons in tobacco smoke induce CYP1A2, the enzyme that performs about 95% of caffeine demethylation, raising caffeine clearance by 40-65% and shortening its half-life from roughly 6 hours to 3.5 hours in smokers. Quitting smoking can cause caffeine levels to rise sharply, contributing to jitters, anxiety, palpitations, and insomnia.
smoking + insulin
Smoking reduces subcutaneous insulin absorption through vasoconstriction and worsens insulin resistance through nicotine-driven catecholamine release, oxidative stress, and inflammation, with HbA1c rising progressively with cigarettes per day. Diabetic smokers typically need 15-30% more insulin than non-smokers to achieve the same glycemic control.