Herbs, supplements and HIV

January 2005     View PDF     En español

NIH study cautions use of
St. John’s Wort with anti-HIV drugs

A study conducted by the NIH found a significant interaction between the popular herbal therapy, St. John’s Wort (Hypericum perforatum), and the protease inhibitor, Crixivan (indinavir). Indinavir blood levels were greatly decreased when the two were used together, greatly reducing indinavir’s anti-HIV activity. This can quickly lead to developing resistance to indinavir. People commonly use St. John’s Wort as a mild anti-depressant.

St. John’s Wort is also likely to have the same effect on other protease inhibitors as well as NNRTIs. People who take these drugs are advised not to use St. John’s Wort. Similar problems with drug interactions may occur between the herb and drugs used to treat other life-threatening illnesses, such as heart disease.

One possible limitation of the finding is that it is not clear how it applies to the various forms of St. John’s Wort on the market. There is no way of knowing its quality or how much St. John’s Wort is actually present in the products. Different brands may have a stronger or weaker effect. Also, the methodology of the study has not been fully described yet.

As this study shows, it’s very possible for some herbal and nutritional supplements to lower the effectiveness of anti-HIV drugs or other medications. People who use complementary therapies should always discuss possible interactions with their doctors and pharmacists.