Herbal remedies and anticoagulant therapy.
Herbal remedies, considered to be both safe and effective by most consumers, may interact with conventional drugs. Warfarin, a vitamin K antagonist originally derived from the sweet clover plant, has a narrow therapeutic window which can be monitored using prothrombin international normalized ratios (PT-INR). Many herbs can increase the risk for bleeding when combined with warfarin, either by augmenting the anticoagulant effects of the drug (with increased PT-INR levels) or through intrinsic anti-platelet properties (without altering PT-INR levels). The increased risk for bleeding among such patients may be difficult to predict, especially when formulas which contain many herbs are used. Further research into herb-drug interactions is warranted, as are guidelines for the use of herbal remedies by patients on chronic anticoagulation therapy.
Samuels
Noah
N
Unit of Complementary Medicine, Tel Aviv Sourasky Medical Center, Israel. refplus@netvision.net.il
D000925:Anticoagulants / Q000627:therapeutic use*; D001777:Blood Coagulation / Q000187:drug effects; D001792:Blood Platelets / Q000187:drug effects; D004365:Drugs, Chinese Herbal / Q000494:pharmacology / Q000627:therapeutic use; D006470:Hemorrhage / Q000139:chemically induced; D041743:Herb-Drug Interactions; D006801:Humans; D010946:Plants, Medicinal / Q000009:adverse effects*
D000925:Anticoagulants; D004365:Drugs, Chinese Herbal