Impact of Smoking on Drug Metabolism and Therapeutic Outcomes

Cigarette smoking represents one of the most significant environmental factors influencing drug metabolism and therapeutic outcomes in clinical practice. Tobacco smoke contains thousands of chemical compounds, including polycyclic aromatic hydrocarbons that profoundly affect hepatic enzyme systems, particularly cytochrome P450 1A2. This narrative review examines the molecular mechanisms through which smoking alters drug pharmacokinetics, focusing on enzyme induction via aryl hydrocarbon receptor activation. We discuss clinically significant interactions involving antipsychotics, anticoagulants, bronchodilators, and other therapeutic agents, emphasizing the importance of dose adjustments when smoking status changes. The review also explores pharmacodynamic interactions and provides evidence-based recommendations for clinical management during smoking cessation. Understanding these interactions is essential for optimizing pharmacotherapy and ensuring patient safety across diverse clinical populations.