How to judge an herbal remedy
How do you determine usefulness? It’s a matter of efficacy, safety, quality, and cost.
TABLE 3
7 herbal medicines associated with serious adverse effects*
| COMMON (LATIN) NAME | INDICATION | ADVERSE EFFECTS (EXAMPLES) |
|---|---|---|
| Aloe vera (Aloe barbadensis) | Various | Juice may cause intestinal pain and electrolyte loss |
| Feverfew (Tanacetum parthenium) | Migraine prevention | “Post-fever syndrome” after discontinuation (migraine, anxiety, insomnia, muscle stiffness) |
| Hawthorn (Crataegus) | Congestive heart failure | Additive effects with other cardiac glycosides |
| Kava (Piper methysticum) | Anxiety | Toxic liver damage |
| St. John’s wort (Hypericum perforatum) | Depression | Increased clearance of a range of prescribed drugs |
| Tea tree oil (Malaleuca alternifolia) | Skin problems (external) | Allergic reactions |
| Valerian (Valeriana officinalis) | Insomnia | Morning hangover |
| * This is a sampling only. Also, without positive safety data, herbal medications cannot be considered safe for pregnant or nursing women. | ||
Uneven quality marks herbal medicines
The quality of an herbal preparation contributes to its efficacy and safety. Herbal dietary supplements usually are unregulated as drugs and can vary widely in quality—to the point of being ineffective.7,16
In the United States, herbal preparations must meet the requirements set forth in the Dietary Supplement and Health Education Act (DSHEA) of 1994. Thus, they are marketed without FDA approval of their efficacy and safety. The DSHEA prohibits companies from making medical claims for dietary supplements, but does allow structure or functional claims. If safety concerns arise, the burden of proof lies not with the manufacturer, but with the FDA.
Many experts believe this regulation is insufficient to guarantee consumer safety and argue for it to be changed.16 In Europe, new legislation will soon require efficacy to be based on bibliographic data, and safety will be governed as it is with conventional drugs.17
Not enough data to base decisions on cost
As a general rule, clinicians should try to recommend treatments that save money for patients and the health-care system. Although herbal medications are relatively inexpensive, few proper economic analyses exist.18,19 So far, only 1 cost evaluation20 of an herbal medicine has been published. This study involved treatment of symptomatic chronic venous insufficiency and compared the cost-effectiveness of compression stockings with that of an extract of horse chestnut seeds; the treatments were comparable.
For the prescribing physician, this means decisions cannot be based on conclusive cost-analyses. Until such studies are available, decisions must be informed by our knowledge of the efficacy, safety, and quality of herbal medications.
One of 5 Ayurvedic herbal medicine products may contain potentially toxic levels of lead, mercury, and/or arsenic, according to a study in the December 15 issue of JAMA. The Ayurvedic tradition is a holistic healing system that originated in India. When researchers tested Ayurvedic products produced in South Asia and sold in the Boston area, 14 of 70 contained heavy metals. If taken according to the package directions, the preparations would exceed published standards for the metals, some of them by a huge margin.
Pharmaceuticals in an herbal remedy?
Among other hazards detected in herbal products are undeclared prescription drugs mixed into the ingredients of some Chinese preparations, according to the FDA. And last May, Consumer Reports identified 12 dietary supplements “too dangerous to be on the market,” yet all were readily available in stores or online. They include comfrey, androstenedione, chaparral, and kava.
Pose the question
All the more reason to ask patients what products they may be using. Ask specifically about herbal or natural remedies, since many people do not consider them drugs and fail to disclose them to physicians.
—The editors
