Feds Eye Viagra-Blindness Reports<br /><br />Small Number Of Viagra Users Going Blind<br /><br />May 27, 2005 1:05 pm US/Eastern<br />WASHINGTON (AP) Federal health officials are investigating rare reports of blindness among some men using Viagra and other impotence drugsbut caution that this type of vision loss also is linked to the same illnesses that lead to impotence.<br /><br />The questions about the impotence drugs come at a time when federal regulators and the drug industry are facing criticism about what they do to ensure the safety of drugs already on the market.<br /><br />The Food and Drug Administration has 43 reports of varying degrees of vision loss, including blindness, among users of the drugs: 38 among Viagra users, four among Cialis users and one among Levitra users, said spokeswoman Susan Cruzan.<br /><br />The FDA now is in discussions with the makers of the drugs about whether the labels should contain a disclosure that in very rare cases, users had developed blindness.<br /><br />We take this seriously, Cruzan said.<br /><br />The makers of Cialis, Eli Lilly & Co. and ICOS Corp., already have voluntarily added a single-line notice to that drugs label.<br /><br />At issue is NAION, or non-arteritic anterior ischemic optic neuropathy, which causes sudden vision loss when blood flow to the optic nerve is blocked.<br /><br />NAION is considered one of the most common causes of sudden vision loss in older Americans, and estimates suggest there are anywhere from 1,000 to 6,000 cases a year. Risk factors include diabetes and heart diseasetwo of the leading causes of impotence.<br /><br />The routine NAION cases plus overlapping risk factors means it may be impossible for FDA to tease out whether the drugs really increase risk for this eye problem.<br /><br />Viagra maker Pfizer Inc. says about 23 million men worldwide have taken Viagra since its approval in 1998. There is no proof that the drug caused the blindness, stressed Pfizer spokesman Daniel Watts.<br /><br />But the possibility of a link was raised publicly earlier this year, when Dr. Howard Pomeranz of the University of Minnesota reported in an opthalomology journal seven patients who reported NAION vision loss occurring within 36 hours of a Viagra dose.<br /><br />A definite causal relationship cannot be established at this time, Pomeranz wrote.<br /><br />Viagra and its competitors work by slightly dilating arteries so that blood flow in the ***** increases. Whether it affects blood flow to the eye isnt known, but Pomeranz argued that some effect on the optic nerve is plausible.<br /><br />So he urged that ophthalmologists asked NAION patients whether they use impotence drugs, and report any additional cases. Also, Viagra users who suffer NAION in one eye should be cautioned that continued use might raise the risk of vision loss in the other eye.<br /><br />Viagra and its competitors are blockbusters that revolutionized treatment of erectile dysfunction, from a seldom-discussed problem to a $2 billion market. But they already come with serious warnings: Theyre 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.<br /><br />All three also warn about temporary vision changesseeing bluish tinges or having difficulty distinguishing between green and blue. The drugs apparently have a temporary effect on the retina, a completely different issue than NAIONs vision loss.<br /><br />The FDA has been under increasing pressure to investigate reports about the safety of prescription drugs since Merck & Co. yanked its pain reliever Vioxx from the market last year because of its potentially lethal side effects.<br /><br />Merck potentially faces thousands of lawsuits over Vioxx and analysts have estimated its liability may reach $18 billion.<br /><br />Viagra also is at the center of controversy over Medicaids payment for prescriptions of the drug to convicted sex offenders in New York and other states.<br /><br /><br />(© 2005 The Associated Press. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. )
