Study To Be Published In February Edition of British Journal of Ophthalmology
In mid-January 2006 the British Journal of Ophthalmology issued a statement previewing an American study that suggests there is a link between impotence, or erectile dysfunction (ED), drugs and blindness, specifically non-arteritic anterior ischaemic optic neuropathy (NAION). The results of this study, conducted by scientists at the University of Alabama in Birmingham (UAB), will be published in the February 2006 edition of the medical journal.
In particular, this study focused on the ED drugs Viagra, made by Pfizer Inc., and Cialis, made by Eli Lilly & Co. According to the preview statement issued by the British Journal of Ophthalmology (BJO), the UAB scientists investigated a small sample of 76 men who had attended one eye specialist clinic in the U.S. All of the men had histories of heart attack or high blood pressure, and were similar in terms of age, race, and lifestyle. According to the BJO statement, the scientists found among this group those men who had taken Pfizer's Viagra or Eli Lilly's Cialis and had had a heart attack were ten times more likely to develop NAION than men with heart attacks who had not taken either of the ED drugs. NAION can cause permanent loss of vision in one or both eyes.
According to the BJO statement, Dr. Gerald McGwin, the lead scientist in the UAB study, states in the soon-to-be-published report:
"For patients with a history of myocardial infarction (heart attack), we did observe a strong and statistically significant association suggestive of a link between the use of Viagra and/or Cialis and an increased risk of NAION."
A January 17, 2006 article in The Wall Street Journal (WSJ) about the UAB study and BJO statement included this retort by Eli Lilly:
"Aside from the small sample size of the study, it's important to note that there are several other limitations to the authors' findings.
"Some of these include patient recall of medical history and details, the study's retrospective and observational nature, potential interviewer bias and the study population was pulled from a database of only patients who had been treated for eye-related disorders."
According to the same WSJ article, no Pfizer spokespeople were available to comment.
As background, in May 2005 the FDA announced that the agency had received more than 40 reports of non-arteritic anterior ischaemic optic neuropathy, or NAION, involving impotence drugs, but it had not determined at that time whether the impotence drugs were responsible for those blindness incidents. Two facts have complicated the ED drug-blindness issue analysis for the FDA, and all interested parties. The first is that NAION is the most common cause of acute optic nerve disease in people over 50 years old. The second is that most patients who take the impotence drugs have other medical risk factors which make them potentially susceptible to NAION.
Some products liability lawsuits have been filed in the U.S. on behalf of patients who have developed NAION after taking an ED drug.
(Posted by: Tom Lamb)