The ads say if it lasts more than a few hours to seek immediate medical attention. Can you imagine THAT Emergency Room visit. And when they lay you down on the stretcher ...
Do you know how this line of drugs was discovered? I did a brief stint as a contractor at a major pharma company (who has a product in this market) and my supervisor told me the story. Viagra was initially meant as some kind of heart or blood pressure drug. It failed in patient tests. But when the researchers asked for the remainder of the test samples to be returned after the failure of the tests, the men all refused to give their remaining pills back.