American Ginseng Affects Prescription Blood Thinners 35978

American Ginseng Affects Prescription Blood Thinners

CHICAGO--Previous studies have linked intake of some herbal productswith reduced efficacy of certain pharmaceuticals. The most recent example waspublished in the Annals of Internal Medicine (141, 1:23-7, 2004) (www.annals.org), in which researchers linked intake of American ginseng withreduced efficacy of the prescription anticoagulant warfarin.

Conducted at the University of Chicago, the study involved 20 healthyvolunteers who received warfarin for three days during the first and fourth weekof the month-long study, plus American ginseng or placebo beginning in thesecond week. Researchers found ginseng intake significantly reduced peak plasmawarfarin levels and the drug's anticoagulant effect.

In a related Patient Summary (141, 1:I-58, 2004), the Annals editorssuggest doctors ask their patients about ginseng use, and note larger doses ofwarfarin may be necessary to achieve the desired effects on blood clotting inpatients taking ginseng.