Viagra Side Effects: It may cause sudden vision loss, loss of hearing . For at least 30 million American men distressed by impotence, Viagra may seem like THE wonder drug. But it’s not. Sure, it’s vastly effective in reversing erectile dysfunction. But the drug, known chemically as sildenafil citrate, has a number of equally distressing side effects — and a few downright dangerous ones.
Sudden loss of hearing in one ear, sudden loss sight and abnormal vision are among the more frightening side effects.