(NaturalNews) The FDA has announced an immediate change to the labeling of drugs in a family that includes popular impotence drugs, warning that they may lead to sudden, severe and potentially permanent hearing loss.The erectile dysfunction drugs in the phosphodiesterase type 5 (PDE5) class include Pfizer's Viagra, Eli Lilly's Cialis and GlaxoSmithKline's Levitra. Also receiving a label change will be blood pressure drug Revatio.The FDA reviewed side effect reports on the drugs after a case study was published in thein 2007, reporting that a 44-year-old man had suffered sudden hearing loss after only 15 days on Viagra. Upon review, the FDA uncovered 29 post-approval reports of patients undergoing sudden hearing loss from PDE5 drugs. In two-thirds of cases, the hearing loss appeared to be permanent. Hearing loss was sometimes, but not always, accompanied by dizziness or ringing in the ears. The majority of cases involved only one ear."Because some level of hearing loss is usually associated with the aging process, patients on these drugs may not think to talk to their doctor about it," said Janet Woodcock, the FDA's chief medical officer.The FDA advises all patients on PDE5 erectile dysfunction drugs to stop taking the medication immediately upon the first sign of sudden hearing loss, and to seek immediate medical care."Because Revatio is used to treat a potentially life-threatening condition, the FDA does not recommend [that] patients abruptly stop taking this medication," the agency said. Such patients "should consult their physician if they experience sudden problems with their hearing.""The fact that the FDA is just now finding out about the risk of sudden hearing loss from impotence drugs demonstrates the failure of its drug approval process to identify serious health risks before drugs are approved," said consumer health advocate Mike Adams. "The truth is that most newly-approved prescription drugs are unleashed upon the population as large-scale experiments, and neither the drug's manufacturer nor the FDA really has any idea of the true dangers of the drug."