Pharmacies and natural food stores are lined with shelves of herbal supplements that are thought to treat a variety of diseases and conditions. But for people taking prescription medications, these seemingly harmless supplements can cause adverse drug interactions that can actually put them at risk.
St. John's wort is used to treat anxiety, depression, stomach upset, insomnia, and fluid retention. It's also used topically to treat nerve pain, burns, and other skin issues. But St. John's wort has also been found to interfere with the processing of the same brain chemicals that are acted upon by antidepressants. For this reason, experts suggest people avoid taking St. John's wort and an antidepressant together.
The herbal supplement ephedra, sometimes called "herbal fen-phen," is used by people as a weight loss supplement and stimulant, though it has been officially banned for sale in the U.S. Ephedra can cause adverse reactions with stimulants, decongestants, and caffeine. People with heart disease, diabetes, hyperthyroidism, glaucoma, or enlarged prostate should not take this supplement.
Many take ginseng to improve concentration, memory, the ability to handle stress, and athletic endurance. It is also used to treat such conditions as depression, anxiety, cystic fibrosis, and cancer. However, ginseng has been known to interfere with the blood thinner Coumadin (warfarin), and people should not take this supplement with this medication.
Kava is a type of "herbal sedative" that some use as a calming, anti-anxiety med. But experts say this supplement will react poorly with sedatives, antipsychotics, sleeping pills, and alcohol. Some who have taken this supplement have also developed skin irritations that doctors say may be due to an immune reaction triggered by the herb.
Many people take ginko biloba to improve memory and concentration, to increase blood flow, and to treat eye problems and dizziness. But this supplement has been found to interact poorly with aspirin, as well as with the anti-clotting drugs Coumadin (warfarin), Plavix (clopidogrel), Ticlid (ticlopidine), and Persantine (dipyridamole).