Dietary supplements, which include substances known as botanical and herbal medications, are available without prescription and, unlike over-the-counter medications, are considered to be nutritional supplements rather than drugs*. These substances are marketed in the United States without FDA or other governmental premarketing review of efficacy or safety, and with little government oversight of purity, variations in potency, or adverse effects. The burden of proof of harm lies with the FDA, before a product can be removed from the market. Purified nonherbal nutritional supplements such as coenzyme Q10 and melatonin are also used widely by the general public in pursuit of “alternative medicine.” For many herbal products and nutritional supplements, evidence from controlled clinical studies for their medical effectiveness is incomplete or nonexistent. A summary of the intended uses of some herbal products and nutritional supplements is presented in Table 61–1.
TABLE 61–1Common intended uses of some botanical or nutritional supplements. ||Download (.pdf) TABLE 61–1 Common intended uses of some botanical or nutritional supplements.
|Botanical or Nutritional Supplement ||Common Intended Use |
|Echinacea ||Decrease duration and intensity of cold symptoms |
|Ephedra (Ma Huang) ||Banned as supplement by FDA; treatment of respiratory ailments such as bronchitis and asthma, and as a CNS stimulant |
|Garlic ||For cholesterol lowering and atherosclerosis |
|Ginkgo ||Treatment of intermittent claudication, and cerebral insufficiency and dementia |
|Ginseng ||Improvement of physical and mental performance |
|Milk thistle ||Limitation of hepatic injury and as an antidote to Amanita mushroom poisoning |
|Saw palmetto ||Improvement in symptoms of benign prostatic hyperplasia |
|St. John’s wort ||Treatment of mild to moderate depression |
|Coenzyme Q10 ||Improvement of ischemic heart disease and for Parkinson disease |
|Glucosamine ||Reduction of pain associated with osteoarthritis (sulfate formulation) |
|Melatonin ||Decrease jet lag symptoms and as a sleep aid |
Leaves and roots of three echinacea species (Echinacea purpurea, E pallida, and E angustifolia) contain flavonoids, polyacetylenes, and caffeoyl conjugates.
In vitro studies have shown that echinacea has cytokine activation and anti-inflammatory properties. There is some evidence for the efficacy of aerial (above-ground) parts of E purpurea plants in the early treatment of colds. Pooled clinical trials using echinacea for cold prevention show a small risk reduction of 10%, but none of the individual trials show a statistically significant benefit.
3. Toxicity and drug interactions
Unpleasant taste and gastrointestinal effects may occur, sometimes with dizziness or headache. Some preparations have a high alcohol content, but no drug interactions have been reported. Echinacea should be used with caution ...