NIH Research: Garlic Supplements Reduce Blood Levels of Saquinavir
Originally published in the AIDS Read 12(2):60, 2002
Researchers have found that garlic supplements can cause a potentially harmful side effect when combined with a type of medication used to treat HIV/AIDS. Investigators from the NIH observed that garlic supplements sharply reduced blood levels of the anti-HIV drug saquinavir.
"In the presence of garlic supplements, blood concentrations of saquinavir decreased by about 50 percent among our study participants," explains the study's senior coauthor Judith Falloon, MD, an AIDS clinical researcher at the National Institute of Allergy and Infectious Diseases. "We saw a definite, prolonged interaction. The clear implication is that doctors and patients should be cautious about using garlic supplements during HIV therapy," she says.
For the first 3 days of the study, 9 healthy, HIV-negative volunteers received doses of the protease inhibitor saquinavir. The research team drew samples from the volunteers' blood to measure their baseline levels of saquinavir in the bloodstream.
Next, the volunteers took garlic caplets twice daily for 3 weeks. When the researchers again analyzed blood samples, the average overall levels of saquinavir had decreased 51%, and the average maximum concentrations had fallen 54%. Even after a 10-day "washout" period with no garlic supplements, when the volunteers again used only the protease inhibitor for 3 days, their blood levels of saquinavir still averaged about 35% lower than the expected baseline amount.
The study results appear in the January 15, 2002, issue of Clinical Infectious Diseases.
