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Evidence-based medicine: group rates efficacy of herbal treatments, compiles safety data.

SAN DIEGO -- A group based at Massachusetts General Hospital has begun to rate the efficacy of herbal medicines according to published evidence.

"Our mission is to form a clearing-house, central repository, or encyclopedia for this kind of data," said Catherine UIbricht, Pharm.D., a pharmacist at the hospital and a chief editor of the Natural Standard Research Collaboration in Cambridge, Mass. The group provides reviews of the data on herbal medicines and alternative practices, using methods like those of their mentors at the Cochrane Collaboration.

Currently, there is no other source of such rigorously researched, evidence-based information, particularly on post-market surveillance, including safety and drug-herb interactions, Dr. UIbricht said at a meeting on alternative medicine sponsored by the American Hospital Association.

The German Commission E report, which many in the naturopathic community cite as an authority on herbs, has no detailed safety information and contains no systemic analysis of the data, she said.

About 400 researchers and clinicians are involved in the collaboration, with 45 translators who work with non-English publications.

Dr. UIbricht discussed the evidence and safety for the 10 most popular herbs, with the Natural Standard grade for each clinical application: A signals definitive evidence of benefit; B represents quality evidence of benefit that is not definitive, with positive animal data; C means that the data are less than rigorous (such as those from small trials or case-cohort studies), conflicting, or derived only from laboratory or animal studies; D signifies fair evidence showing no effect.

* Black cohosh. Black cohosh got a B for menopausal symptoms, but only a C for joint pain. Black cohosh has known interactions with hormonal medications and anticoagulants.

* Evening primrose oil. For atopic dermatitis, evening primrose oil gets a B. Although it is used for many other conditions, ranging from preeclampsia to asthma to Raynaud's disease, the evidence earns only a C or D. It should be avoided in seizure disorders and during pregnancy.

* Saw palmetto. For benign prostatic hypertrophy, saw palmetto earns an A. But it only gets a C for male pattern baldness and underactive bladder. Saw palmetto has known drug and herb interactions.

* Valerian. Valerian earns a B for insomnia, a C for anxiety disorder, and a D for sedation. Valerian should be avoided in liver disease, pregnancy, and breast-feeding, and it can cause drug interactions.

* St. John's wort. For severe depression, St. John's wort gets only a B or a C, but it gets an A for mild to moderate depressive disorder. It gets a C for anxiety disorder, obsessive-compulsive disorder, perimenopausal symptoms, and premenstrual syndrome. St. John's wort may interfere with oral contraceptives and should not be used by persons with a thyroid disorder because it can alter TSH levels. It has a many drug interactions.

* Echinacea. Echinacea shows antimicrobial properties in vitro, and it earns a B for treating upper respiratory infections. But it receives a C for prevention of upper respiratory tract infections, radiation-induced neutropenia, and cancer. It gets only a D for genital herpes. Echinacea interacts with antibiotics, antifungals, and certain immunosuppressants, among other drugs.

* Bilberry. Bilberry contains flavonoids that may inhibit prostacyclin synthesis and impair coagulation and platelet aggregation. It is used for vascular conditions and eye diseases, earning a C for all of them, except it gets a D for improvement of night vision.

* Cranberry. Cranberry earns a B for prevention of urinary tract infection. Large doses should be avoided in diabetes, pregnancy, and breast-feeding. It gets a C as an antiviral, an antioxidant, an antifungal, and for cancer prevention. It also earns a C for the treatment of urinary tract infections, kidney stones, and dental plaque.

* Wild yam. Wild yam may have hormonal and lipid-lowering properties, but it gets only a C for menopausal symptoms and hyperlipidemia. Wild yam can cause skin rash, uterine contractions, and hypoglycemia.

* Ginger. Ginger gets a B for chemotherapy-induced and pregnancy-associated nausea, but only a C for nausea after surgery and for motion sickness. It also gets a C for rheumatoid arthritis, osteoarthritis, arthralgias, and muscle pain.

For more information visit the Natural Standard Research Collaboration's Web site at


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Title Annotation:Clinical Rounds
Author:Kirn, Timothy F.
Publication:Internal Medicine News
Geographic Code:1USA
Date:Apr 1, 2004
Previous Article:Clarification.
Next Article:Increasing data: complementary therapies gain scientific clout.

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