Federal health officials are probing reports of blindness among dozens of men who used Viagra and other impotence drugs ? but at the same time cautioning that the vision loss can be linked to the same illnesses that lead to impotence.
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The Food and Drug Administration disclosed Friday that it was in discussions with the makers of Viagra, Cialis and Levitra about what the labels of those drugs should say about the rare cases of varying degrees of vision loss, including blindness. The maker of Cialis already has voluntarily added a one-line mention to its label.
At issue is sudden vision loss when blood flow to the optic nerve is blocked, a condition called NAION or non-arteritic anterior ischemic optic neuropathy.
The FDA has 43 reports of NAION among the impotence drug users: 38 for Viagra, four for Cialis and one for Levitra, said spokeswoman Susan Cruzan.
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Those are rare numbers, given that Viagra alone has been used by 23 million men worldwide since its approval in 1998, according to maker Pfizer Inc.
Also complicating the question: NAION is considered one of the most common causes of sudden vision loss in older Americans, and estimates suggest there are anywhere from 1,000 to 6,000 cases a year. Risk factors include diabetes and heart disease, two of the leading causes of impotence.
Still, "we take this seriously," Cruzan said.
Side effects include vision problems
The questions come at a time when federal regulators and the drug industry are facing criticism about what they do to ensure the safety of drugs already on the market. Pr ...