Pfizer: No proof Viagra causes blindness

Global pharmaceutical company Pfizer said a review concluded Viagra did not increase patients’ risk of blindness, but that it was still working with US federal regulators to update the drug’s label to reflect rare reports of vision-loss.

Last month, the US Food and Drug Administration said it had 38 reports of blindness caused by a a condition called NAION or non-arteritic anterior ischemic optic neuropathy among users of Viagra.

But Pfizer said it conducted a review of all post-marketing ocular event reports has concluded that there was no evidence of increased risk of blindness among patients taking Viagra.

While the FDA had concluded no causal relationship between Viagra and NAION had been established, Pfizer has agreed to include on the Viagra label that these reports exist in order to inform physicians and patients.

“After more than 10 years of rigorous clinical study and worldwide safety monitoring of a medicine used by more than 27 million men, there is no evidence to suggest a link between Viagra and blindness or other serious ocular events,” said Joseph Feczko, Pfizer’s chief medical officer.

“In addition, several studies specifically looking into the effect of Viagra in the eye by Pfizer as well as independent ophthalmologic experts found Viagra to have no serious adverse effects on the eye.”

Pfizer said it is the company’s understanding the FDA has asked that similar information be included in the labels of all oral erectile dysfunction medicines.

The FDA reported there were instances of NAION among those taking Cialis, which is made by Eli Lilly and ICOS as well as Levitra, which is marketed by Bayer AG, GlaxoSmithKline and Schering-Plough.