A small number of men die after ingesting Viagra. Most of these deaths are attributed to the high risk of mortality these men have due to cardiovascular disease. The US Food and Drug Administration (FDA) and manufacturer Pfizer Inc are aware of the deaths but believe the drug continues to be safe for patients when correctly prescribed.
But some pharmacoepidemiologists argue that the safety of Viagra (sildenafil), hailed as a significant new treatment for erectile dysfunction (ED), should be questioned. They say postmarketing surveillance isn't as stringent as it should be—that an unanswered question remains: are some men who take Viagra dying because of the underlying disease or because of the drug?
Mitka M. Some Men Who Take Viagra Die—Why?. JAMA. 2000;283(5):590-593. doi:10.1001/jama.283.5.590-JMN0202-2-1