FDA Recalls Herbal Remedies--A Healthnotes Newswire Opinion
In February 2002, the U.S. Food and Drug Administration (FDA) recalled two herbal products, PC-SPES and SPES, after testing by the California Health Department revealed the apparent presence of prescription drugs in these products. PC-SPES, which is used by some men as an alternative treatment for prostate cancer, was said to contain warfarin, a blood-thinning drug that can cause serious bleeding. SPES, a product that is claimed to enhance the immune system, contained alprazolam (Xanax®), a drug used to treat anxiety and panic attacks. The apparent identification of these drugs in nonprescription herbal formulas has raised new concerns about quality control and adulteration of herbs. However, additional information seems necessary before these incidents can be unequivocally be classified as cases of adulteration.
There has been one report of excessive bleeding occurring in a man who was taking PC-SPES.1 However, the warfarin concentration in this patient's blood was not high enough to explain his abnormal bleeding. Chemical analysis of the PC-SPES product he was using suggested the presence of compounds that, though distinct from warfarin, could potentially be mistakenly identified as warfarin using currently available laboratory methods. That observation raises the possibility that what the California Health Department identified in PC-SPES was something other than warfarin.
The other herbal product, SPES, was found to contain alprazolam, a drug in the class known as benzodiazepines (which includes diazepam [Valium®] and lorazepam [Ativan®]). However, benzodiazepines are known to occur naturally in some plants. In one study, seven different benzodiazepines (including diazepam and lorazepam) were identified in wheat, potato, or both of these foods.2 The amount of these compounds was extremely small and medically insignificant; for example, one would have to consume thousands of slices of bread to obtain a single therapeutic dose of diazepam. Based on these observations, it is conceivable that alprazolam occurs naturally in one of the components of the SPES formula. It would be useful to know how much alprazolam was found by the California Health Department, and whether the drug is present in freshly harvested samples of any of the herbs that make up SPES.
PC-SPES is an herbal preparation that has become popular as an alternative treatment for prostate cancer. The name of the product is derived from the abbreviation for "prostate cancer" and from the Latin word for "hope." PC-SPES contains eight herbs: Dendranthema morifolium tzvel (chrysanthemum), Isatis indigotica (Isatis), Glycyrrhiza glabra (Licorice) and Glycyrrhiza uralensis, Ganoderma lucidum (Lucid gandermal), San-qi ginseng (Panax pseudo-ginseng), Rabdosia rubescens, Serenoa repens (saw palmetto), and Scutellaria baicalensis.
Some studies have demonstrated a beneficial effect of PC-SPES in men with prostate cancer. In a study of 32 patients with "androgen-dependent" prostate cancer (a relatively early and mild form of the disease), all 32 patients had a reduction in the level of prostate-specific antigen (PSA; a measure of disease activity) after treatment with PC-SPES for approximately one year.3 Other markers of disease progression also showed improvement. In the same study, 19 of 35 people with "androgen-independent" prostate cancer (a more advanced form of the disease) showed at least temporary improvement in their PSA levels. Other researchers have reported similar results with PC-SPES.4
PC-SPES has been associated with a number of side effects, some of which are severe. The most serious adverse reaction has been the formation of blood clots that sometimes lodge in the lungs (thromboembolism), which occurred in three (4.5%) of 67 participants in one study. However, thromboembolism is common in men with prostate cancer, so it is not clear whether PC-SPES was actually responsible for this complication. Other adverse effects have included allergic reactions, abnormal breast enlargement (gynecomastia), breast tenderness, loss of libido, erectile dysfunction, leg cramps, and diarrhea. Because of these potential side effects, individuals should never take PC-SPES without the close supervision of a doctor.
To reduce the risk of thromboembolism, some doctors have recommended that patients using PC-SPES also take blood-thinning medication, such as heparin or warfarin. However, each of these drugs can cause excessive bleeding, and combining PC-SPES with one of these medications falls clearly within the realm of complex medical therapy. Thus, there can be no justification for the presence of warfarin in an over-the-counter herbal product. However, whether PC-SPES does, indeed, contain warfarin is not entirely clear.
1. Weinrobe MC, Montgomery B. Acquired bleeding diathesis in a patient taking PC-SPES. N Engl J Med 2001;345:1213–4.
2. Wildmann J, Vetter W, Ranalder UB, et al. Occurrence of pharmacologically active benzodiazepines in trace amounts in wheat and potato. Biochem Pharmacol 1988;37:3549–59.
3. Small EJ, Frohlich MW, Bok R, et al. Prospective trial of the herbal supplement PC-SPES in patients with progressive prostate cancer. J Clin Oncol 2000;18:3595–603.
4. Pfeifer BL, Pirani JF, Hamann SR, Klippel KF. PC-SPES, a dietary supplement for the treatment of hormone-refractory prostate cancer. BJU Int 2000;85:481–5.
Alan R. Gaby, MD, an expert in nutritional therapies, served as a member of the Ad-Hoc Advisory Panel of the National Institutes of Health Office of Alternative Medicine. He is the Medical Editor for Clinical Essentials Alert, is the author of Preventing and Reversing Osteoporosis (Prima, 1994), and co-author of The Natural Pharmacy, 2nd Edition (Healthnotes, Prima, 1999), the A–Z Guide to Drug-Herb-Vitamin Interactions (Healthnotes, Prima, 1999), Clinical Essentials Volume 1 and 2 (Healthnotes, 2000), and The Patient’s Book of Natural Healing (Prima, 1999). Currently he is the Endowed Professor of Nutrition at Bastyr University of Natural Health Sciences, Kenmore, WA.
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