The information provided is for educational purposes only and is not intended to replace discussions with a healthcare provider. In these studies, involving about patients, analyses of patient diaries showed no effect of VIAGRA on rates of attempted intercourse about 2 per week , but there was clear treatment-related improvement in sexual function: per patient weekly success rates averaged 1. Many people have no side effects or only mild ones. Brand names Why is this medication prescribed? Stop taking VIAGRA and call your healthcare provider right away if you have any sudden vision loss sudden hearing decrease or hearing loss. Based upon measurements of sildenafil in semen of healthy volunteers 90 minutes after dosing, less than 0. One-third to one-half of the subjects in these studies reported successful intercourse at least once during a 4-week, treatment-free run-in period.Keep in mind that Viagra isn’t approved in the United States to treat PE. And it’s not recommended in current PE treatment guidelines from the American Urological Association. In most countries, including the United States, Viagra is not available without a prescription. However, in , Viagra became available over the counter in the United . Examples of Viagra’s more commonly reported side effects include: headache. flushing (temporary warmth, redness, or deepening of skin color) stuffy nose. indigestion (upset stomach) mild vision.