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CAM Lecture on 'Reverse Herbology,' Oct. 26 in Masur

What happens when people taking prescription medications also use herbal supplements? There is increasing evidence that herbs have pharmaceutical properties; they can enhance, cancel out or adversely affect the clinical efficacy of prescription drugs, sometimes with life-threatening consequences.

One notable example is the well-known herbal St. John's wort, which many people take to treat depression, anxiety or sleep disorders. Research has found that St. John's wort promotes the metabolism of many drugs including the immunosuppressant cyclosporine, the HIV protease inhibitors indinavir and nevirapine, the cancer drug irinotecan, the anticoagulant warfarin and even oral contraceptives. St. John's wort, taken with these drugs, can reduce their concentrations to dangerously low levels and make the drugs ineffective.

Dr. Steven A. Kliewer
The molecular basis for this kind of herb-drug interaction is now understood, thanks to the research of scientists such as Dr. Steven A. Kliewer, the next speaker for the Distinguished Lectures in the Science of Complementary and Alternative Medicine, a series hosted by the National Center for Complementary and Alternative Medicine.

On Tuesday, Oct. 26, Kliewer will give a lecture entitled "Reverse Herbology: Predicting and Preventing Adverse Herb-Drug Interactions," from noon to 1 p.m. in Masur Auditorium, Bldg. 10. Kliewer is professor of molecular biology and pharmacology and holds the Nancy B. and Jake L. Hamon distinguished chair in basic cancer research at the University of Texas Southwestern Medical Center's Graduate School of Biomedical Sciences. Kliewer's discoveries have had a significant impact on the fields of endocrinology and pharmacology, particularly in the area of drug metabolism. He discovered the xenobiotic receptor PXR ,which is activated by St. John's wort and other herbs and is responsible for an important class of drug-drug interactions. His work has significant implications for drug development and drug interactions. A practical consequence of this work is that new drugs can be screened efficiently for harmful interactions with other medications.

Kliewer will present recent findings regarding activation of PXR by St. John's wort and other herbs and will discuss how this knowledge can be applied to predict and prevent harmful interactions between herbs and prescription drugs.

All are invited to attend the lecture. It will also be webcast at For reasonable accommodation, contact Terence Hope at (301) 402-9686, or the Federal Relay at 1-800-877-8339.

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