FDA Looking Into Blindness-Viagra Link By LAURAN NEERGAARD, AP Medical Writer
WASHINGTON - Federal health officials are examining rare reports of blindness among some men using the impotence drug Viagra.
The Food and Drug Administration still is investigating, but has no evidence yet that the drug is to blame, said spokeswoman Susan Cruzan.
This type of blindness is called NAION, or non-arteritic anterior ischemic optic neuropathy. It can occur in men who are diabetic or have heart disease, the same conditions that can cause impotence and thus lead to Viagra use.
The FDA has 50 reports of the blindness. Viagra has been taken by more than 23 million men worldwide.
"We take this seriously," said FDA's Cruzan.
On its Web site, Viagra manufacturer Pfizer Inc., states: "The most common side effects of Viagra are headache, facial flushing, and upset stomach. Less common are bluish or blurred vision, or being sensitive to light. These may occur for a short time." That language had been available before the current inquiry.
Pfizer spokesman Daniel Watts confirmed Friday that the drugmaker was in discussions with the FDA about adding a disclosure to Viagra's label to say that in rare cases, men taking Viagra had developed blindness. However, he said there is no proof that Viagra caused the blindness. He said that men who take Viagra often have high blood pressure and high cholesterol, which are also associated with the conditions that can cause blindness.
FDA is working with Pfizer to determine what, if any, information about the condition should be added to the drug's label. The story was first reported by CBS News.
Viagra was approved by the government in 1998. It may aid in the treatment of enlarged hearts that can result from high blood pressure, tests on animals indicate.
Viagra, approved to treat erectile dysfunction, should not be used by men with heart conditions whose doctors have warned them not to have sex. Also, patients taking drugs that contain nitrates have been warned not to take Viagra because of sudden, unsafe drops in blood pressure.
The drug's label also warns of erections lasting longer than four hours, painful erections lasting longer than six hours, headache, flushed skin and vision problems.
Pfizer Inc., the New York-based maker of Viagra, said in its most recent quarterly filing with the Securities and Exchange Commission that sales of the drug rose 5 percent — to $438 million in the first quarter of the year. Pfizer also said at the time that Viagra had a 68 percent worldwide market share.