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28.05.05, 10:43
Updated: 08:11 PM EDT
FDA Probes Reports of Blindness With Viagra
By LAURAN NEERGAARD, AP
The FDA has 42 blindness reports, 38 among users of Viagra, above, and four
among users of Cialis.
WASHINGTON (May 27) - Federal health officials are probing reports of
blindness among dozens of men who used Viagra and other impotence drugs - but
at the same time cautioning that the vision loss can be linked to the same
illnesses that lead to impotence.
The Food and Drug Administration disclosed Friday that it was in discussions
with the makers of Viagra, Cialis and Levitra about what the labels of those
drugs should say about the rare cases of varying degrees of vision loss,
including blindness. The maker of Cialis already has voluntarily added a one-
line mention to its label.
At issue is sudden vision loss when blood flow to the optic nerve is blocked,
a condition called NAION or non-arteritic anterior ischemic optic neuropathy.
The FDA has 43 reports of NAION among the impotence drug users: 38 for
Viagra, four for Cialis and one for Levitra, said spokeswoman Susan Cruzan.
Those are rare numbers, given that Viagra alone has been used by 23 million
men worldwide since its approval in 1998, according to maker Pfizer Inc.
Also complicating the question: 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 disease, two of the leading causes of impotence.
Still, ''we take this seriously,'' Cruzan said.
The questions 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. Pressure on the FDA to investigate reports of side effects has
increased since Merck & Co. yanked its pain reliever Vioxx from the market
last year because of potentially deadly heart trouble.
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.
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.
All three also warn about temporary vision changes - seeing bluish tinges or
having difficulty distinguishing between green and blue. The drugs apparently
have a temporary effect on the retina, a different issue from NAION.
Viagra also is at the center of controversy over Medicaid's payment for
prescriptions of the drug for convicted sex offenders in New York and other
states.
The possibility of a link with blindness was raised publicly earlier this
year, when Dr. Howard Pomeranz of the University of Minnesota reported in an
ophthalmology journal seven patients who reported NAION vision loss occurring
within 36 hours of a Viagra dose.
''A definite causal relationship cannot be established at this time,''
Pomeranz wrote.
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 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, Pomeranz wrote.
Associated Press writers Theresa Agovino in New York and Elizabeth Wolfe in
Washington contributed to this story.
AP-NY-05-27-05 19:52 EDT
