Viagra Report Spurs Reaction

A consumer group says it will soon ask the FDA to add the strongest warning possible – a black box – to Viagra and other drugs in the same class after reports of blindness among dozens of men who used the impotence drugs, reports CBS News Correspondent Sharyl Attkisson.

In some respects, the writing may have been on the wall. The makers of Cialis, a Viagra rival, have updated their label warning of rare cases of blindness. The makers of Levitra say they're unaware of any issue with that drug.

But consumer advocate Dr. Sidney Wolfe flagged the potential risk of vision loss in all three drugs in his book "Worst Pills Best Pills," and he alerted the FDA seven years ago when sporadic reports first surfaced.

"We will be asking the FDA in the next couple of weeks to put a black box warning on all three of these drugs' labeling," says Wolfe, "and also to require when a patient gets a prescription filled, that they get an informative and accurate information sheet that warns, among other things, about vision loss."

On Thursday, Attkisson was first to report that a small number of men have gone blind after taking Viagra.

"I've pretty much accepted that my eyesight is not going to come back," said Jimmy Grant, who started using Viagra in 1998, when he was 57. "But I've also pretty much accepted that Viagra done it."

Eye specialist Dr. Howard Pomeranz was first to flag the potential problem in 1998.

"I can't tell you how many other people have contacted me thinking that there may have been an association," said Pomeranz, "that they had raised the issue with their physicians and their physicians had said, 'Well, I'm not aware of that.'"

The FDA says no definite link has been proven, but agrees the public needs to be warned promptly. Just how to do that is what they're discussing. Pfizer says there's no evidence of more vision loss in men taking Viagra than similar men who don't.

Attkisson notes that when talking about a lable change, there are a lot of discussions and negotiations between the FDA and the drug company. It's unlikely the product would be removed from the market.

CBS News Correspondent Elizabeth Kaledin explains the vision loss is often called "the stroke of the eye." There is a certain group of the population that is at high risk, and that would be the same group at risk for having a stroke.

Those would be men over 50 with diabetes, high blood pressure, heart disease. Coincidentally, that is the same population of men most likely to be taking Viagra, notes Kaledin. So until the FDA can prove or disprove a causal link, that population should really check with their doctor about this.

Viagra and its competitors are blockbuster drugs that revolutionized treatment of erectile dysfunction, and they already come with serious warnings: They're not to be used by men who take nitrate-containing drugs, because the interaction could cause deadly drops in blood pressure, or by men with heart conditions whose doctors have warned that sex itself could be too much exertion

Viagra and its competitors work by slightly dilating arteries so that blood flow in the penis increases. Whether it affects blood flow to the eye isn't known, but Pomeranz argued that some effect on the optic nerve is plausible.

So he urged that ophthalmologists ask patients whether they use impotence drugs, and report any additional cases. Also, Viagra users who suffer blindness in one eye should be cautioned that continued use might raise the risk of vision loss in the other eye, Pomeranz wrote.

Big money is at stake. Pfizer Inc. said in its most recent quarterly filing with the Securities and Exchange Commission that sales of Viagra rose 5 percent — to $438 million — in the first quarter of the year.

Pfizer shares declined Friday on the New York Stock Exchange after news of the blindness cases.