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Newsletters July 2010 - Jefferson Cardiology Happenings

Herbal Products Create Problems

In the U.S. more than 15 million people use herbal products or high dose vitamins. There are more visits to providers of complementary and alternative medication than visits to primary care doctors. Such products result in out of pocket costs of $30 billion dollars annually. Use of these products by persons taking prescription medications could result in adverse drug interactions. Widespread use of herbal products exists despite lack of scientific evidence of benefit or safety. In the February 9 issue of the Journal of the American College of Cardiology, there is a review from the Mayo Clinic about herbal products and interactions with cardiac patients.

The largest proportion of complementary and alternative medications is derived from plants or plant products. As such, these products are regarded as food products and not subjected to regulations as are prescription medications. Thus the manufacturers are exempt from documenting benefit or safety before or after releasing their products. Despite the claims that the products are natural and safe, many adverse effects can occur that can produce life-threatening problems.

As many senior citizens taking prescription medications also take complementary products and as there has been limited research about interactions, dangerous drug interactions may occur. In the following paragraphs commonly used herbal products will be reviewed as well as their cardiovascular complications and drug interactions.

Some herbal products have direct effects on the cardiovascular and clotting systems and others have indirect effects by resulting in potentially serious drug interactions. Such agents include St. John’s wort, motherwort ginseng, ginkgo biloba, garlic, grapefruit juice, hawthorn, saw palmetto, danshen, echinacea, tetrandrine, aconite, yohimbine, gynura, licorice and black cohosh. For lack of space only some of these agents will be discussed. A separate table will provide a more complete summary.

St. John’s wort is among the top 10 bestselling herbs in the U.S. It is used to treat depression, anxiety, sleep disorders, colds, shingles, and AIDS. It also has been used to spread on skin for pain relief and as an enema for ulcerative colitis.

St. John’s wort may affect a liver enzyme system that acts to metabolize or break down medications. The effect on the enzyme system will be to reduce blood levels of medications affected by this system resulting in possible heart rhythm disturbances, high blood pressure. Organ transplant patients may have up to 50% reductions of a medication given to prevent transplant rejection. Also St. John’s wort will reduce effectiveness of Coumadin and statin medications. Another reaction will be to cause low blood sugar with some diabetic medications and dangerous complications with some antidepressant medications.

Ginseng is advertised as a stimulant that increases vigor, sexual potency, longevity, and benefits diabetes management. Ginseng has been shown to have capability to raise and lower blood pressure. In traditional Chinese herbal medicine, this product has been used for angina, heart attack, and heart failure. However, there is no scientific evidence of benefit for any of these conditions. Ginseng has been shown to cause change in behavior, diarrhea, and may cause kidney damage. Also it may reduce Coumadin effects and produce effects similar to estrogen. Neonatal death has been reported and is related to maternal use.

Ginkgo biloba has been used for dementia. Recent randomized clinical trials showed no difference between ginkgo and placebo. Ginkgo has also been used for cardiovascular disease, cerebrovascular disease, peripheral vascular disease, impotence, stress, depression, premenstrual syndrome, and inner ear dysfunction. When used with Coumadin or other blood thinning agents, the risk of bleeding is increased. Intracranial hemorrhage has been reported with ginkgo biloba and blood thinning agents.

Grapefruit juice inhibits a liver enzyme system. Blockage of this system may interfere with metabolism of statins, estrogen, terazosin, or calcium channel blocking agents. Patients taking these agents should limit grapefruit consumption as this will raise the level of the concerned medication in their blood.

Saw palmetto is used by more than two million men for treatment of symptoms of an enlarged prostate. Clinical trials have shown no benefit and no evidence of reduced residual bladder volume after urination. This agent may increase bleeding with Coumadin and cause pancreatitis, hepatitis and surgical complications with cataract surgery.

In short, most herbal products have not been scientifically evaluated and little is known about their action and safety. Randomized controlled studies have not been done to establish efficacy and safety. There is not effective regulation of these agents. The only requirement for the manufacturer is to send a product label to the FDA. Thus, a new supplement can be introduced and marketed very quickly without restriction despite containing unregulated herbal ingredients. There is no supervision of quality control. Published studies have shown that more than 40% of herbal products do not contain the concentration of active ingredients claimed or cheaper ingredients may be substituted. Contamination may also be a problem.

There are concerns about false advertisements in the media and some claim doctor recommendations. The sales of these products can only be halted if the product is deemed dangerous and proof is sent to the Secretary of Department of Health and Human Services. As these products are not routinely tested, the chances are reduced that the FDA would find a product unsafe and take action to remove the product from the marketplace. Consumers are unlikely to report an adverse effect from a supplement and manufacturers rarely report adverse effects. A report from the inspector general indicated that less than 1% of adverse effects are reported to the FDA.

Large numbers of vulnerable people are taking supplements. In one clinical trial, 64% of patients with atrial fibrillation or other cardiac conditions took supplements. Over 50% took supplements that could interact with Coumadin or other cardiac medications. In another clinic, 46% of Coumadin patients took supplements. In one study, 40% of participants indicated that both supplementary and prescription medications together was better than taking either alone.

In short, patients wishing to mix complementary and prescription medications could be at risk. Patients should tell their doctors what complementary medications they take. Even then, physicians may be limited in their ability to evaluate with limited information available about supplement safety and interactions. The public may benefit from better scientific study of complementary products and more effective regulation. It is uncertain if improved regulation will be available in the near future. Some leadership may come from the National Center for Complementary and Alternative Medicine which has an ongoing study evaluating the effectiveness of ginkgo biloba for prevention of dementia.

A publication of Jefferson Cardiology Association
Alan D. Bramowitz, M.D. | Michael S. Nathanson, M.D. | Gennady Geskin, M.D.

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