Topic overview

Start with the big picture

Herb–drug interactions arise through pharmacokinetic changes, such as CYP enzyme or P-glycoprotein modulation and reduced absorption, or through pharmacodynamic effects that add to or oppose a medicine’s action. The examples in this topic illustrate why the direction of an interaction matters: enzyme induction may lower drug exposure, while inhibition may raise it; additive effects can increase risks such as bleeding, sedation, or arrhythmia. Interactions may also affect anticoagulation, glucose control, liver safety, and hormone-related therapy. The lesson organises these risks by mechanism and clinical context, and considers onset, duration, patient counseling, monitoring, documentation, and regulatory classification. This preview highlights key patterns; the full lesson develops their clinical application.