Herbal product-drug interactions mediated by induction

Br J Clin Pharmacol. 2006 Jun;61(6):677-81. doi: 10.1111/j.1365-2125.2006.02684.x.


Despite their common use, it is not widely recognized that herbal medicines can alter the efficacy of coadministered prescription drugs. Constituents in herbs interact with nuclear receptors to enhance metabolizing enzyme and/or transporter activity leading to reduced drug concentrations. Although St John's wort was the first and most frequently reported source of induction-style herb-drug interactions, this knowledge has not yet changed its current availability. This type of interaction is likely to be relevant to other herbal products. Caregivers need to be aware of the issues and options for therapeutic management.

MeSH terms

  • Adaptation, Physiological
  • Cytochrome P-450 Enzyme System / metabolism*
  • Herb-Drug Interactions*
  • Humans
  • Hypericum*
  • Plant Preparations / metabolism*


  • Plant Preparations
  • Cytochrome P-450 Enzyme System