FDA probing reports of blindness among some men who use Viagra

NEW YORK – The Food and Drug Administration is investigating 43 reports of sudden partial blindness in men who used three impotence drugs – Viagra, Cialis and Levitra.

However, the FDA said it is not clear whether the drugs played a role since conditions that lead to the erectile problem can themselves cause vision loss.

The number of blindness cases – 38 for Viagra, four for Cialis and one for Levitra – is minuscule compared with the more than 28 million men who have used the drugs. The vision loss – nonarteritic ischemic optic neuropathy or NAION – is essentially a stroke of the eye. NAION can occur in patients with diabetes or heart disease, conditions that can lead to impotence.

In the past, some men have experienced a blue haze following the use of impotence drugs, but that side effect is not what occurred in the 43 men. And manufacturers caution men with heart problems or those who take other drugs containing nitrates not to use the impotence pills because the combination could cause a fatal blood pressure drop.

More than 23 million men have used Viagra since the baby blue pill made its 1998 debut. About 5 million men have used Cialis since approval in 2003. Levitra also became available in 2003. The company could not provide prescription figures Friday. The FDA has not connected vision loss to use of the impotence drugs, an agency spokeswoman said Friday, but added the agency is taking the reports seriously. Quinn would not say how the FDA learned about the cases of blindness. “Basically, we have those reports, but haven’t determined there’s a direct cause,” she said.

The FDA is in discussions with Pfizer Inc., which makes Viagra; Eli Lilly & Co., which makes Cialis; and GlaxoSmithKline, which sells Levitra in the United States, concerning possible labeling changes.