FDA To Consider Warning Label Changes for Viagra, Cialis, and Levitra
The FDA is investigating numerous reports of a possible serious side effect from the use of Viagra and other impotence, or erectile dysfunction (ED), drugs. The primary adverse reaction at issue is nonarteritic ischemic optic neuropathy (NAION), described as "stroke of the eye," in men who used Viagra and other impotence, or erectile dysfunction (ED), drugs. NAION occurs when blood flow is cut off to the optic nerve, which injures the nerve, causes sudden vision loss, and results in varying degrees of permanent vision loss, including blindness. An FDA spokesman said that the FDA has 43 reports of NAION among the impotence drug users: 38 for Viagra; four for Cialis; and, one for Levitra.
Complicating the FDA's investigation of these various side effect reports is the fact that NAION is considered one of the most common causes of sudden vision loss in older Americans; it is estimated that there are anywhere from 1,000 to 6,000 new NAION cases a year. Moreover, the risk factors for developing NAION include diabetes and heart disease, which are two of the leading causes of impotence. Thus the issue becomes whether a man's development of NAION is the result of using the ED drug or due to the underlying medical condition which caused his impotence.
The FDA said on May 27, 2005 that the agency was in discussions with the makers of Viagra, Cialis, and Levitra about what the package insert labels of those ED drugs should say about the rare cases of NAION. The package insert label for Cialis already has a one-line mention of this vision-loss side effect. The labels for all three ED drugs currently warn about temporary vision changes -- such as seeing bluish tinges, or having difficulty distinguishing between green and blue. That warning language, however, has to do with these impotence drugs having a temporary effect on the retina, which is a different medical condition, and not NAION.
The possibility of a link between Viagra and blindness was raised earlier in 2005 by Howard Pomeranz, M.D., associate professor of ophthalmology at the University of Minnesota Medical School. Dr. Pomeranz reported in the March 2005 issue of the Journal of Neuro-ophthalmology, the cases of seven men, aged between 50 and 69 years, who developed typical features of NAION within 36 hours after their ingestion of Viagra for erectile dysfunction. Dr. Pomeranz wrote in his article that seven other NAION cases involving Viagra had been previously reported. The onset of NAION within hours after ingestion of Viagra in 14 patients supports an association between the use of the drug and NAION. Dr. Pomeranz cautioned, however, "A definite causal relationship cannot be established at this time."
(Posted by: Tom Lamb)