USRF Research

Cases of Blindness in Men on Viagra Reported to FDA
Concern about NAION Raises Possibility of Labeling Change

Source: CBS News and Other USRF Sources

Pfizer refutes notion that Viagra can cause blindness (6-27-05)

FDA Mandates Label Change (7-5-05)

Petition for Label Change

Washington, DC, May 26, 2005---The U.S. Food and Drug Administration is studying cases of blindness reported in men using the oral impotency drugs Viagra, Cialis, and Levitra. The story was first reported by CBS news and confirmed by FDA spokesperson Susan Cruzan, who said that 43 reports of NAION (non-arteritic anterior ischemic optic neuropathy) had been reported---38 in men using Viagra, 4 using Cialis, and one using Levitra. Such occurrences, if found to be causally related, would be an extremely rare complication, considering the tens of millions of men who have used these drugs since the FDA first approved Viagra in 1998.

“A definite causal relationship cannot be established at this time,” said Dr. Howard Pomeranz, a University of Minnesota ophthalmologist who first reported NAION in a Viagra-user in 2000. A total of 14 cases of NAION, each occurring within minutes to hours after Viagra ingestion, was reported by Dr. Pomeranz in the March, 2005 issue of the Journal of Neuro-Opthalmology. All reported cases had atherosclerotic risk factors such as diabetes, hypertension, or hyperlipidemia. These risk factors are also associated with erectile dysfunction, the indication for Viagra; however, the close temporal relationship between onset of blindness and drug ingestion has raised FDA scrutiny. “We are taking this seriously,” said FDA spokesperson Cruzan.

Pfizer, maker of Viagra (sildenafil), has posted to its website the statement that among 13,000 men in 103 clinical trials, NAION was not observed.

NAION is the most common acute optic nerve disease, with thousands of cases reported annually in the U.S. The disorder is associated with swelling of the optic nerve head, possibly as a result of altered blood flow, leading to ischemia. NAION is typically heralded by blurred vision and/or visual field defects, before progressing to complete loss of vision. The Viagra-class of drugs (PDE-5 inhibitors) have long been known to have potential ocular side-effects, which are well-described in the package inserts, but blindness has not been previously reported.

A USRF study describing Viagra efficacy vis-à-vis E.D. severity and partner’s perception was published in 1999.

A comparison of Viagra, Levitra and Cialis was the subject of a recent USRF Special Report.



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