A total of 38 cases of blindness caused by non-arteritic anterior ischemic optic neuropathy (NAION) were reported to the FDA during May 2005.
Although this condition was at first linked to the use of Viagra, Pfizer now believes erectile dysfunction and NAION may be comorbid at least to the extent that both conditions share the same risk factors. Therefore a concordance may exist between rates of erectile dysfunction and the development of NAION regardless of the treatment used.
“There is no evidence that Viagra causes blindness or any other serious ocular condition,” said Dr Joseph Feczko, Pfizer’s chief medical officer. “Men taking Viagra are at no greater risk for blindness, including vision loss from NAION, than men of similar age and health not taking the medicine.”
While the FDA found no causal relationship between Viagra and NAION, Pfizer has agreed with the agency to include a warning on the Viagra label to help inform physicians and patients. Other companies are also expected to include similar information in the labels of their oral erectile dysfunction medicines.