Herb/drug interactions
This article was originally published in The Tan Sheet
Executive Summary
Ginseng and ginkgo biloba inhibit CYP3A4 metabolism in study of 22 healthy individuals between ages 21 and 55, Harbor-University of California at Los Angeles investigators state. Six-phase study explored effect of ginseng, ginkgo and St. John's wort on metabolism of Rx antihypertensive drug nifedipine. Confirming previous reports, St. John's wort was found to have an inducing effect on CYP3A4 1("The Tan Sheet" Feb. 14, 2000, p. 19). HIV-1 protease inhibitors are substrates of the CYP3A4 isozyme. "Caution must be exercised when these herbs are combined with medications that are CYP3A4 substrates," M. Smith, MD, et al., stress. Five other posters presented at ASCPT annual meeting examined drug interactions involving St. John's wort