Erectile dysfunction drugs may harm hearing

FDA requires Viagra, Levitra, Cialis and blood pressure med Revatio manufacturers to add hearing loss risk warnings on the label.

WASHINGTON (CNN) -- Men taking any of the three erectile dysfunction drugs - Viagra, Levitra or Cialis - or the blood pressure medication Revatio may be at increased risk for sudden hearing loss, prompting Food and Drug Administration officials to require label changes by the manufacturer.

Revatio has the same active ingredient as the other drugs.

The FDA is now requiring the drug labels "to display more prominently the potential risk of sudden hearing," according to the agency's Web site.

The FDA also recommended that men taking one of the ED drugs and experiencing hearing loss should immediately stop taking the drug and see their physician.

However, patients taking Revatio and experiencing hearing loss should not discontinue taking this drug, according to the FDA, because that could have life-threatening consequences. Those patients are urged to see their physicians immediately.

The FDA is requiring manufacturers of the entire class of drugs -- called Phosphodiesterase Type 5 Inhibitor, or PD-5 inhibitors -- to prominently prominently display the risk of sudden hearing loss or hearing impairment on their drugs' labels.

The FDA says all manufacturers have agreed to the change their labels.

"This is basically a public health announcement to let people decide if they want to take the drug," Dr. Robert Boucher told CNN. Boucher is an ear, nose and throat specialist for the FDA who reviewed reports of sudden hearing loss in patients taking these drugs.

According to FDA spokeswoman Rita Chappelle, the FDA began investigating the possible link between hearing loss and ED drugs following the publication of an article for ear, nose and throat specialists in last April's Journal of Laryntology and Otology. The study reported on a man taking Viagra who had experienced sudden hearing loss.

This prompted the FDA to look for other reports of sudden hearing loss. The FDA found a total of 29 post-marketing reports which involved patients reporting ringing in their ears, vertigo and/or dizziness. In most cases, the hearing loss only occurred in one ear, and for about one third of patients, the hearing loss was temporary.

Boucher said "these 29 adverse event reports date back to 1996, when Viagra, the first impotence drug, was approved."

"So we're only talking about a couple cases per year," he said.

He said 40 millions prescriptions of all four drugs have been filled worldwide so far.

"This is a very small number of cases, but because we're talking about a person's ability to hear, we thought it was important to make the label clear that this is a possible event," Chappelle told CNN.

Sudden hearing loss can happen to anyone, but it is generally uncommon.

According the National Institutes of Health, there about 4,000 new cases of sudden hearing loss in the United States each year. Usually hearing loss can be caused by blood flow blockage as a result of diabetes or other illness, smoking, age and antibiotics.

Pfizer manufactures Viagra and Revatio and Eli Lilly manufactures Cialis. Levitra, developed by GlaxoSmithKline and Bayer HealthCare, is jointly promoted in the United States by GSK and Schering-Plough Corporation.

Representatives from Pfizer (Charts, Fortune 500) and Eli Lilly (Charts, Fortune 500) stressed to CNN that this is a "class label change" for all such drugs. In separate statements, Pfizer and Lilly representatives told CNN "the FDA is making this change in the interests of patients so that patients can make informed decisions regarding PD-5 medications."

GlaxoSmithKline (Charts) did not return calls, but Schering-Plough (Charts, Fortune 500) noted that "based on patient reports, all occurrences of sudden hearing loss in patients taking Levitra were temporary."

CNN's Amy Burkholder and Ben Leach contributed to this report.

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