Many people take herbal supplements because they feel the supplements can treat various disorders with less side effects than prescription medications. Taking these supplements without consulting a pharmacist or physician, however, is not advisable. Many interact with over-the-counter medicines. For instance, ginkgo, feverfew, kava, ginger and dong quai increase the risk of bleeding when taken with nonsteroidal anti-inflammatory drugs. Herbal supplements can interact with prescription medications, as well.
What Are Herbal Supplements?
According to the University of Maryland Medical Center, herbal medication is the term to describe any flowers, leaves, berries, bark, roots or seeds of a plant which are used to treat diseases. The ancient Egyptian and Chinese cultures used herbal medication, and so did the Native American and African cultures. Chemists did not start extracting and changing plant ingredients until the 19th century, and gradually, over-the-counter drugs and prescription medications began to be used more than herbal medicines. The use of herbal supplements is now increasing, however.
Physicians' Concerns About Herbal Supplements
Although herbal supplements may treat various conditions, physicians are concerned about their use because the manufacturers do not have to prove their effectiveness before selling them. The Food and Drug Administration did establish regulations requiring manufacturers to report all serious problems caused by their herbal supplement products. They must ensure that the product has the correct ingredients, correct label, is sold in the right amount and is not contaminated. Physicians also have concerns that some of the herbal supplements can interact with prescription medications.
Warfarin, Blood Pressure Medication and Herbal Supplements
Warfarin, also known as coumadin, is a prescription medication that prevents the formation of blood clots. St. John's wort, ginseng, danshen, ginger, feverfew, kava, ginkgo, garlic, dong quai and coenzyme Q all interact with warfarin, according to George Delgado Jr., Pharm.D., coordinator of emergency pharmacy services at Detroit Receiving Hospital, writing in "Tintinalli's Emergency Medicine." Warfarin is not as effective when taken with St. John's wort, ginseng and coenzyme Q. All of the other herbal supplements increase the risk of bleeding when taken with warfarin. Taking ginseng or ginger with blood pressure medication can cause an increase or decrease in blood pressure.
Various Interactions
Ginseng and garlic cause an abnormally low blood glucose level when taken with diabetic medication. Ginkgo, feverfew, kava, ginger and dong quai increase the risk of bleeding if people take them with dipyridamole, clopidogrel or ticlopidine, all anti-platelet prescription medications. Taking ginkgo with the antidepressant trazodone can put that person into a coma, according to George Delgado Jr. St. John's wort not only lowers the effectiveness of warfarin, but that of oral contraceptives, certain antidepressants, simvastatin cholesterol-lowering medication, certain asthma medications, and digoxin heart medicine.
References
- Food and Drug Administration: Current Good Manufacturing Practices (CGMPs) Dietary Supplements
- "Tintinalli's Emergency Medicine: A Comprehensive Study Guide"; Judith Tintinalli, M.D., Gabor Kelen, M.D. et al.; 2004
- University of Maryland Medical Center: Herbal medicine
