Many users of ephedra-based supplements take a whole lot more than that, further compounding the risks. "Athletes in particular often assume that if a little is good, more is better," said Earnest, who has worked in the supplement industry. "And your body adapts, like it does to coffee. You take it for a week or two weeks, and suddenly you find you need more to get the same sensation."
Earnest said he knows of bike racers who take 10 times the recommended dose of these products to get up for a race. Before the race has even begun, he said, the bicyclists' heart rates have sometimes reached 150 beats per minute, and "they're ready to explode."
Add 100 degrees of summer heat, a heavy quilt of humidity--plus the exercise--and you put an enormous strain on the heart, doctors agree. As the heart beats frantically, the body sweats, losing water, which lowers blood volume, which can in turn further increase blood pressure, cardiologists said. "The body is already releasing adrenaline, and the sympathetic nervous system is highly stimulated," said Ricuarte, "and you're combining this with the product, which is doing the same things. It's excessive stimulation. In vulnerable individuals, it's a recipe for big problems."
Industry executives have long argued that ephedra has a good safety record: Millions of people use the supplements each year, and there were only 140 complaints to the FDA between June 1997 and March 1999. But the FDA does not require supplement makers to report consumer complaints, and industry critics believe there are thousands of side-effects caused by the products that the FDA never hears about.
According to Gurley, several surveys now show that consumers are less likely to attribute headaches, nausea, dizziness or other symptoms to supplements than to prescription drugs they're taking. "Even when people are having some strange reaction or symptoms," he said, "they don't think of the supplements. They think the supplements are somehow 'natural' and wouldn't cause problems."
The FDA took action against drugs containing ephedrine compounds in the early 1980s. But because ephedra supplements are not regulated as drugs, the FDA has limited power to act. "The important thing to know," Gurley said, "is that these are active drug entities, whether they're called drugs or not."
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Effect on the Body
Ephedra compounds are derived from the ma huang shrub native to China. Even small doses of these extracts noticeably stimulate the central nervous system, researchers say, and heighten alertness. But documenting potential adverse effects and who's at risk has been difficult.
Researchers consider 25 milligrams to be the recommended, "therapeutic" dose, usually given with about 200 milligrams of caffeine. One dose usually produces:
* Heart rate quickens.
* Bronchial airways open, making more oxygen available.
* Blood vessels constrict, increasing blood pressure.
Some people react more strongly to ephedra compounds than others. In a recent study of adverse events reported to the FDA, researchers found that a variety of problems were definitely or probably due to the supplements. They included:
* Palpitations, and/or rapid heart rate
* Cardiac arrest, or sudden death
\o7 Source: New England Journal of Medicine, Dec. 21, 2000
* Sampling of popular products containing ephedra extracts:
Up Your Gas
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* Label ingredients indicating ephedra compounds:
* Ingredients that contain other stimulants, such as caffeine:
Source: University of Arkansas College of Pharmacy