The honeymoon may be over for Viagra

This pharmaceutical phenomenon now faces new reports of waning efficacy after two years; attempts to reign in prescribing practices; and competitors on the horizon.

By Victoria Stagg Elliott, AMNews staff. Oct. 1, 2001.

It may seem like Viagra, one of the pharmaceutical industry's big success stories, is increasingly coming under siege.

Researchers are reporting that, for some patients, it loses efficacy or needs to be administered at a higher dosage after two years.

The German government recently announced that it would be reviewing prescription guidelines after several hundred European deaths were connected to the drug.

And competitors are in phase III clinical trials and nipping at the drug, which defined the erectile dysfunction segment of the prescription drug market.

When Viagra (sildenafil citrate) burst onto the scene in 1998, it triggered both worries about possible adverse cardiac events and talk show host jokes. The laughter has since died down to giggles, as respectable figures such as former presidential candidate Bob Dole spoke out about their Viagra use, and most studies showed the drug to be safe. In addition, adverse events have not been linked directly to the drug -- rather to the overall health of those who take it or to abuses of it.

"Many of the patients who have erectile dysfunction may also have coronary artery disease because they do share a number of risk factors and common pathophysiology. But the drug is very safe. One just has to be aware of caveats in its use," said Howard Herrmann, MD, professor of medicine with the University of Pennsylvania in Philadelphia, who has been researching the cardiac effects of the drug.

Several months after approving Viagra, the Food and Drug Administration strengthened its warnings about combining the drug with nitrates. The agency also emphasized that sex is a risky activity that in itself can increase cardiac risk. [...]