Viagra has been linked to blindness and vision loss in some users, the maker of the anti-impotence drug said Friday. Pfizer Inc. has received 23 reports of such side effects since Viagra was introduced in 1998, spokesman Daniel Watts told the Bloomberg financial news agency. The New York-based company is in talks with the U.S. Food and Drug Administration (FDA) to update Viagra's label to "reflect those rare occurrences", he said. Viagra, with 1.68 billion dollars in sales last year, has been used by about 23 million men worldwide. Viagra users might be prone to vision loss already because of illnesses that cause erectile dysfunction, such as diabetes and high blood pressure, which are also linked to sight problems, Watts said. The FDA said there have been 38 cases in which men taking Viagra lost vision because of a condition called non-arteritic ischemic optic neuropathy. Spokeswoman Suzanne Trevino confirmed that the FDA is working with Pfizer. She advised people with concerns to talk to their doctors. Pfizer shares were down 2.2 per cent from Thursday's close, trading at 28.26 dollars around midday on Wall Street. --SP 2143 Local Time 1843 GMT
