53: Herbal Supplements

Published on 27/02/2015 by admin

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CHAPTER 53 Herbal Supplements

James Duke, MD, MBA

1 How does the Federal Food and Drug Administration regulate herbal medications?

In 1994 the Food and Drug Administration (FDA) implemented the Dietary Supplement Health and Education Act, which outlines the regulation of botanicals, called dietary supplements. Under this act manufacturers of alternative medications operate under less rigid guidelines than prescription pharmaceutical companies. The lack of rigorous regulation has resulted in a lack of standardization of doses and purity, contamination with undeclared pharmaceuticals and heavy metals, failure to report adverse events, and no requirement to demonstrate safety or efficacy. However, when presented with a supplement with obvious toxicity issues such as the stimulant effects of ephedra, the FDA does intervene to limit its availability; ephedra is no longer available as an over-the-counter product.

2 What is the incidence of herbal medicine use in the surgical patient population? What are commonly used herbal medicines?

In 2001 over $4 billion was spent on herbs and other botanical remedies. Reported use varies widely, but a self-administered questionnaire of preoperative patients found an incidence of about 40%. Often these are taken without input from a physician. The number of individuals using herbal remedies is rising annually. Use in women is higher than in men, and patients with either neoplastic disease or human immunodeficiency virus have also been noted to use supplements with greater frequency. Supplements most commonly used include vitamins (especially vitamins E and C), garlic (Allium sativum), fish oil, ginkgo biloba (ginkgo), ginseng, Zingiber officinale (ginger), Hypericum perforatum (St. John’s wort), Echinacea angustifolia, valerian, 2-amino-2-deoxyglucose sulfate (glucosamine), chondroitin 4-sulfate, chamomile, kava, and Tanacetum parthenium (feverfew). Oriental patients who receive concoctions from Chinese herbalists often receive more potent compounds with many different herbs contained therein.

3 How can commonly used herbal medicines adversely affect the surgical patient?

Although these supplements are considered natural, they are not free of harmful side effects. They have central nervous and cardiovascular effects (e.g., ephedra) and interact with prescription drugs. For example, St. John’s wort induces the cytochrome P-450 enzymes, accelerating the breakdown of cyclosporine, antiretroviral drugs, digoxin, and warfarin, resulting in a fall in drug levels to subtherapeutic concentrations. Nephrotoxic, hepatotoxic, and carcinogenic effects have been associated with products containing kava, comfrey. Of greatest concern in the perioperative period are effects on coagulation. Vitamin E, garlic, fish oil, ginkgo, ginseng, ginger, and feverfew have anticoagulant potential.

4 What are the risks involved in consuming ephedra?

Ephedra alkaloids have been marketed as a way to boost energy and lose weight. These compounds are powerful cardiovascular and central nervous system stimulants, and severe hypertension, dysrhythmias, myocardial infarction, acute psychosis, seizures, cerebrovascular accidents, and death have been associated with their use. It may be particularly toxic when combined with caffeine. Many hundreds of people have been hospitalized after their use and, as mentioned previously, the FDA has prevented its over-the-counter availability.

5 Review the effects of vitamin E

Vitamin E is consumed for the prevention and treatment of cardiovascular disease, diabetes mellitus, and some forms of cancer. Vitamin E is an antioxidant that prevents the formation of free radicals, but high doses may increase bleeding caused by antagonism of vitamin K–dependent clotting factors and platelet aggregation. Concomitant use of vitamin E and anticoagulant or antiplatelet agents, including aspirin, clopidogrel (Plavix), dalteparin (Fragmin), enoxaparin (Lovenox), heparin, ticlopidine (Ticlid), and warfarin (Coumadin) may potentiate the risk of bleeding.

6 What are the reported benefits and adverse effects of fish oil?

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