Cialis and Viagra Eye Damage Not Found in Study Funded by Lilly

Although the impotence drugs Viagra and Cialis have been associated with the development of a rare form of eye damage that could cause suddent blindness, new research funded and designed by Eli Lilly & Co. found no reports of the vision side effect among a small group of healthy men under 65 years old who were studied.

Viagra, which is marketed by Pfizer, and Cialis, marketed by Lilly, are popular prescription drugs for treatment of erectile dysfunction, generating sales of $1.9 billion and $1.2 billion respectively last year.

Concerns about potential vision side effects associated with the drugs, particularly Viagra, emerged several years ago. The FDA has received reports about a number of users suffering a rare eye disorder within 48 hours of taking one of the drugs, known as non-arteritic anterior ischemic optic neuropathy or “NAION.”

Viagra and Cialis both work by increasing blood flow to blood vessels in the penis, but can also effect the eye. This could cause vision problems in one or both eyes, with blurring, blue tint, white spots or complete loss of vision that has been reported to be permanent in some patients.

Eli Lilly funded and helped design a study to evaluate the risk of eye damage associated with their drug Cialis and Pfizer’s drug Viagra. The results of the study were published online this week by the Archives of Opthalmology.

Researchers evaluated 244 healthy men between 30 and 65 years old, a third of which used Viagra, a third of which used Cialis and a third of which used a placebo for six months. After measuring the electrical impulses from their eyes and conducting ophthalmologic exams, researchers found no reports of the eye damage that has been linked to the drugs.

According to the National Institutes of Health, about 6.2 percent of U.S. men are unable to achieve an erection. However, the problem is much higher among older men, with 16.7% of men in their 60s experiencing erectile dysfunction.

According to an interview with Bloomberg News, the lead author of the study, Raj Maturi, indicated that the data should provide relief to the average patient that Viagra and Cialis side effects do not cause significant vision problems and can be taken long-term.

However, the research was only done on health men who were under 65 years old, some of which only had mild erectile problems. In addition, the researchers have acknowledged that the results may not apply to individuals with diabetes or other conditions that could make them more susceptible to eye damage.

In July 2005, the FDA required that information about NAION be added to the warning labels for Viagra, Cialis and Levitra, a third drug in the same class. Users were cautioned to stop taking the drugs and call their doctors if they experienced sudden or decreased vision loss in one or both eyes. Among the risk factors identified for the eye damage are diabetes and heart disease, which are also two of the leading causes of impotence.

Pfizer currently faces a large number lawsuits which have been filed by users who suffered from Viagra side effects they allege caused vision problems or hearing loss. All of the federal Viagra lawsuits are consolidated in an MDL, or multidistrict litigation, in the U.S. District Court for the District of Minnesota.