Postsurgical Risks of Herbal Supplements

E-Newsletter No. 8

Once used by only a small segment of the population, the use of so-called "natural" herbal supplements has in recent years become widespread. Herbal supplements have become increasingly popular, and, since the passage of the Dietary Supplement Health and Education Act of 1994, also largely unregulated with respect to purity, potency, and claims made for particular products. Of particular concern is the question of poorly understood and often even more poorly publicized effects of herbal preparations. Consumers may find themselves lulled into a false sense of security by buzzwords such as "organic" and "all natural".

In the present study taken from the Journal of the American Medical Association, July 11, 2001, Dr. Michael Ang-Lee and his colleagues investigate one limited set of unintended consequences arising from the use of eight selected herbal supplements. The investigators examined a group of the more widely used herbal preparations: Echinacea, ephedra, garlic, ginkgo, ginseng, kava, St. John’s wort, and valerian. Their principle concern was whether and how any of these substances might contribute to perioperative complications. Other points are addressed that have bearing on non-surgical practice as well.

The researchers investigated the effects of these herbal medications beginning with searches of Medicine and Cochrane Collaboration databases. They gathered information for each substance concerning usage patterns, drug effects, pharmcokinetics, and drug interactions both proved and suspected. The results are collected and published in a series of brief digests as well as in tabular form.

Highlights for Particular Herbal Preparations Include:

• Echinacea was found to have immunostimulatory effects, which might be problematic especially in patients with asthma or allergies.
• Ephedra (Ma Huang) is a stimulant containing several alkaloids including ephedrine. It has sympathomimetic effects associated with numerous adverse incidents such as interfering with sleep, raising blood pressure, speeding up heart rate, increasing stress response, and formation of kidney stones.
• Garlic reduces blood pressure and can inhibit platelet aggregation, possibly irreversibly.
• Ginkgo Biloba may affect vasoregulation (blood pressure) and appears to inhibit platelet aggregation.
• Ginseng may lower blood sugar levels, as well as inhibit the effects of anticogulants.
• Kava (Piper methysticum) has sedative and anti-anxiety effects. It may potentiate effects of other drugs with sedative effects.
• St. John’s Wort works on neurotransmitter reuptake, and can interact with drugs such as antidepressant SSRIs. It can also increase metabolism of several types of drugs including ethinyl estradiol and cyclosporin.
• Valerian is a sedative, commonly used in herbal sleep preparations. It appears to act similarly to benzodiazepines, should be expected to increase the effect of other sedatives. There have been several case reports of hepatoxicity (liver) associated with use of multi-ingredient preparations containing valerian. Four other cases of hepatoxicity involving long-term use of single-ingredient valerian preparations have also been reported.

New research suggests that patients facing surgery stop taking herbal supplements days, or sometimes weeks, before an operation.

The authors also note that patients who make extensive use of herbal preparations are unreliable self-reporters of their use of these substances. They physician requires accurate knowledge of the patient’s complete medical history, including an accurate knowledge of the patient’s use of herbal preparations. This is important not only because of the effects of these drugs, but because patients who use them may be self-mediating undiagnosed and potentially serious health problems.

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