LOS ANGELES - Many of the pills marketed as safe herbal alternatives to Viagra and other prescription sex medications pose a hidden danger: For men on common heart and blood-pressure drugs, popping one could lead to a stroke, or even death.
'All-natural' products with names like Stamina-RX and Vigor-25 promise an apothecary's delight of rare Asian ingredients, but many work because they contain unregulated versions of the very pharmaceuticals they are supposed to replace.
That dirty secret represents a special danger for the millions of men who take nitrates - drugs prescribed to lower blood pressure and regulate heart disease. When mixed, nitrates and impotency pharmaceuticals can slow blood flow catastrophically, leading to a heart attack or stroke.
An Associated Press investigation shows that spiked herbal impotency pills are emerging as a major public health concern that officials haven't figured out how to track, much less tame.
Emergency rooms and poison control hot lines are starting to log more incidents of the long-ignored phenomenon. Sales of 'natural sexual enhancers' are booming - rising to nearly $400 million last year. And dangerous knockoffs abound.
At greatest risk are the estimated 5.5 million American men who take nitrates - generally older and more likely to need help with erectile dysfunction.
The all-natural message can be appealing to such men, warned by their doctors and ubiquitous TV commercials not to take Viagra, Cialis or Levitra.
James Neal-Kababick, director of Oregon-based Flora Research Laboratories, said about 90 percent of the hundreds of samples he has analyzed contained forms of patented pharmaceuticals - some with doses more than twice that of prescription erectile dysfunction medicine. Other testers report similar results, particularly among pills that promise immediate results.
While no deaths have been reported, the AP found records of emergency room visits attributed to all-natural sex pills in Georgia, Chicago, Philadelphia, San Diego and elsewhere.
Mark B. Mycyk, a Chicago emergency room doctor who directs Northwestern University's clinical toxicology research program, said he is seeing increasing numbers of patients who unwittingly took prescription-strength doses of the alternatives, a trend he attributes to ease of purchase on the Internet and the desperation of vulnerable men. He said he wouldn't be surprised if there'd been undetected deaths from bad herbal pills.
Some men in their 30s who went to emergency rooms after taking herbal sex pills were presumably otherwise healthy, but they showed the transitory side effects of the active ingredients in regulated impotency pharmaceuticals, such as difficulty seeing clearly or severe headaches, records show.
While public health officials don't know the extent of the problem, they agree that incidents are vastly underreported.