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Viagra Side Effect

Men were greeted with a shock after the Food and Drug Administration (FDA) recently confirmed that it was investigating reports of partial vision loss among some users of anti-impotence drugs. A recent study also noted these vision problems, known as non-arteritic anterior ischemic optic neuropathy (NAION), in seven men who had taken Viagra.

Erection Drug Blindness

The FDA has yet to issue a formal ruling. But according to FDA spokeswoman, Susan Cruzan, the agency is currently examining reports of vision problems in 38 men who took Viagra and in four who took a newer anti-impotence drug, Cialis. The lawsuits are already beginning to pile up. Well over 20 million men have taken these anti-impotence drugs, meaning that whatever risk there is of developing vision loss—if there is a risk at all—would seem extremely small. Still, just how serious of a condition is NAION, and what can be done in men who develop it?

NAION

NAION is one of the most common causes of sudden vision loss in older Americans. The condition leads to swelling around the optic disc, a connection point where the optic nerves reach the back of the eye. Ultimately, this swelling compresses the optic nerves and causes a rapid drop in vision. About 6,000 people develop NAION each year, according to the National Eye Institute.

The symptoms are painless and often appear without notice. In a study led by researchers at the University of Iowa, about three quarters of NAION patients first discovered their vision was blurry and impaired after waking up in the morning. The condition starts in one eye and can cause complete blindness if both eyes are eventually affected.

Hysterical Blindness

No one can say for sure. Pfizer, the manufacturer of Viagra, defends the safety of its drug. "A review of 103 Viagra clinical trials involving 13,000 patients found no reports of non-arteritic anterior ischemic optic neuropathy," the company stated. "There is no evidence showing that NAION occurred more frequently in men taking Viagra than men of similar age and health who did not take Viagra."

Andrew Schachat, MD, an ophthalmologist with the Wilmer Eye Institute at Johns Hopkins University, who has no financial ties to Pfizer, is equally skeptical. "With the millions of patients who use Viagra, it is not surprising to find cases of NAION and in fact, one would expect to find some," he said.

The FDA is currently investigating whether there is a connection. Schachat said he doubts Viagra or other anti-impotence drugs cause NAION, "but a careful study would be needed."

The chance that Viagra might lead to NAION was first brought up by Howard Pomeranz, MD, an eye expert at the University of Minnesota. In 2000, he reported the case of a man who developed NAION soon after he took Viagra. There have been several other reports since then. In a study published in the Journal of Neuro-Ophthalmology this past March, Pomeranz noted seven new cases, bringing the total to 14 men who developed NAION possibly because of Viagra. On May 26, the FDA first confirmed to CBS News that they were investigating similar reports in nearly 50 men.

The seven men in Pomeranz's recent study all developed NAION soon after they took Viagra. After taking two blue Viagra pills the day before, one 50-year old man said he felt "a flashbulb go off in my eyes." The onset of vision loss within hours of taking Viagra "supports an association between use of this agent and NAION," Pomeranz wrote. However, NAION appears suddenly in some 6,000 people a year for a variety of unknown reasons. "We don't really know what the natural history of NAION is," said Dickersin. Pomeranz is also cautious about Viagra causing NAION: "A definite casual relationship cannot be established at this time," he noted.

Viagra causing Blindess Conlusion

Recent guidelines from the American Urological Association recommended either Viagra, Cialis or Levitra as the first option for treating erectile dysfunction, which have not changed in light of the recent bad publicity about their potential link to NAION.

In general, as many as 80 percent of men will benefit from these drugs, said Drogo Montague, MD, of the Cleveland Clinic in announcing the new guidelines. Men can try injections, external penis pumps or a penile implant if Viagra or similar drugs fail to work. "For those men who are not helped by these agents, one or more of the remaining treatment options are almost always successful," said Montague.

Sam Fields