A potential drug-herbal interaction between Ginkgo biloba and efavirenz

J Int Assoc Physicians AIDS Care (Chic). Mar-Apr 2012;11(2):98-100. doi: 10.1177/1545109711435364. Epub 2012 Feb 9.


Efavirenz (EFV) is primarily metabolized by cytochrome P450 (CYP) 2B6 and to a lesser extent by CYP3A4. Drugs that significantly inhibit or induce these enzymes would then be expected to increase or lower the levels of EFV potentially resulting in toxicity or therapeutic failure, respectively. The constituents of Ginkgo biloba extract have been demonstrated to induce gene expression of the CYP450 enzymes. We report a case in which a potential drug-herb interaction may have led to virological breakthrough in a patient that was maintained on the same regimen for 10 years. Therefore, a drug-herbal interaction may be expected when these agents are taken concurrently, and we advise clinicians to avoid this combination when possible.

Publication types

  • Case Reports

MeSH terms

  • Adult
  • Anti-HIV Agents / therapeutic use*
  • Benzoxazines / therapeutic use*
  • Drug Interactions
  • Drug Therapy, Combination
  • Ginkgo biloba / adverse effects*
  • HIV Seropositivity / drug therapy*
  • HIV Seropositivity / virology
  • Humans
  • Lamivudine / therapeutic use
  • Male
  • Plant Extracts / adverse effects*
  • Viral Load
  • Zidovudine / therapeutic use


  • Anti-HIV Agents
  • Benzoxazines
  • Plant Extracts
  • Lamivudine
  • Zidovudine
  • efavirenz