Buying prescription drugs online from unknown foreign sources is risky business, and people are being advised by the Food and Drug Administration once again to use care when doing so. A recent analysis of three commonly prescribed drugs purchased by the FDA from a Canadian-advertised Web site showed that the 'generics' were fake, substandard, and potentially dangerous.

'Consumers who believe they are getting equivalent products from reputable sources are being misled and putting their health at risk,' says Dr. Lester M. Crawford, Acting FDA Commissioner. 'This firm shipped drugs that were the wrong strength, including some that were substantially super-potent and that pose real health risks as a result, drugs that didn't dissolve properly, drugs that contained contaminants, and drugs that should not have been given because of potentially dangerous drug interactions,' he says.

The FDA purchased so-called 'generic' versions of Viagra (sildenafil), Lipitor (atorvastatin), and Ambien (zolpidem). None of the drugs has a U.S.-approved generic version, so all of the purchased drugs were unapproved.

The 'generic' Ambien, a controlled substance approved for short-term insomnia, contained too much active ingredient, including one tablet that was nearly double the labeled potency. Taking super-potent Ambien puts patients at risk for central nervous system depression, especially in elderly or debilitated patients.

The 'generic' Lipitor, a drug used for lowering cholesterol, was subpotent and failed to dissolve, providing on average only 57 percent of the active ingredient claimed on the label. It also failed the FDA's purity testing. Subpotent products could present a long-term risk for the various complications of high cholesterol, such as heart disease. Further, the Lipitor product was furnished to the FDA's online purchaser, even though the purchaser said that he was taking the antibiotic erythromycin. Lipitor's label warns against taking these two drugs at the same time.

The 'generic' Viagra, normally sold to treat impotence, contained too little of the active ingredient, failed to dissolve, and had an unacceptable level of impurities.

The FDA warns that, although a Web site may appear to be reputable and may look similar to other retail pharmacy Web sites, many of these are in fact operating from outside the United States and are providing unapproved drugs from unreliable sources. The National Association of Boards of Pharmacy (NABP) has established a program called Verified Internet Pharmacy Practice Sites (VIPPS), designed to certify Web sites that meet industry standards. Consumers should look for the VIPPS certification seal on the site or check with the NABP for a list of VIPPS-certified pharmacies at www.nabp.net/vipps/ to help minimize the risks of getting bad quality drugs from disreputable sources.

FDA Consumer magazine