Viagra, a drug that treats erectile dysfunction, is one of the most counterfeited drugs in the world. Men can order the little blue pill online without a prescription via a quick Internet search and credit card payment. They can also order "all-natural" sexual enhancement alternatives such as Rock Hard for Men or Lightning Rod.
But what are they really getting?
It could be Viagra or its generic version, sildenafil, which dilates blood vessels and helps increase blood flow into the penis during sexual stimulation. Or it might contain tainted chemicals or other prescription drugs.
Drugmaker Pfizer took the unprecedented step last week of creating a website to sell Viagra, which is still under patent, in an effort to thwart online counterfeiters. Pfizer's "buy real Viagra" website comes up first as a paid-sponsor link in a Google search of the terms "generic Viagra" and "buy Viagra".
Men who opt to buy fake Viagra or other sexual enhancement supplements have no idea what they're actually taking because the product labels don't reflect the true ingredients, according to a commentary published earlier this week in the journal JAMA Internal Medicine.
"These supplements might contain the active ingredients found in prescription erectile dysfunction medications -- though made illegally without any quality control -- or they might contain one of more than 45 chemical agents that have never been tested in humans," said Dr. Pieter Cohen, an internist at Cambridge Health Alliance and assistant professor at Harvard Medical School, who co-authored the commentary. "The consumer has become a guinea pig."
On Thursday, the US Food and Drug Administration warned men not to buy Boost -- Ultra Sexual Enhancement Formula because it was found to contain sildenafil. On May 6, the makers of Lightning Rod announced that they were issuing a voluntary recall after the FDA found sildenafil in its "herbal" capsules. The FDA also issued a warning last week against the supplement Vicerex because it contains tadalafil, the active ingredient in the prescription drug Cialis, also used to treat erectile dysfunction.
"These products aren't just sold on the internet," Cohen said. "You can purchase them in local mom and pop stores throughout the Boston area."
Men on nitrate medications for high blood pressure or high cholesterol may be warned by their doctors not to take a prescription erectile dysfunction medication because the drug interactions could cause their blood pressure to drop to a dangerously low level. But Cohen said these men could unknowingly be incurring the same risks with a sexual enhancement supplement that contains the same active ingredients.
Other sexual enhancement supplements, like Rock Hard for Men, have been found to contain tadalafil, along with glibenclamide, an active ingredient in diabetes medications; glibenclamide lowers blood sugar and -- when taken by a person who doesn't have diabetes -- can cause blood sugar levels to drop precipitously low.
"More than a dozen deaths have occurred outside the U.S. from those who have taken [supplements containing diabetes drugs] and fallen into a coma from low blood sugar," Cohen said.
While no deaths have been reported in this country from such sexual enhancement supplements, common side effects from ingredients they may contain include stomach upset, light-headedness, and vision changes.
Bottom line: Men should avoid purchasing any supplements to enhance their sexual performance, Cohen advised, because such products contain unknown ingredients with unknown risks.