★★☆Single study — solid evidence, such as one good trial or a large observational dataset, but not replicated at the top tier.
Sildenafil has a window: thirty minutes to four hours before
The approved dose for erectile dysfunction is 50mg, taken between thirty minutes and four hours before sex, no more than once in a day. It moves to 100mg or down to 25mg.
What the study found
The window is thirty minutes to four hours, once a day at most
The approved dose of sildenafil for erectile dysfunction is 50mg, taken between thirty minutes and four hours before sex, and no more than once in a day. From there it moves up to 100mg or down to 25mg depending on how well it works and how well it is tolerated.
The caveat · Lower start for several groups
A prescribing label sets rules without publishing the data behind them. The starting dose is lower than 50mg for several groups, including anyone already taking a drug that slows sildenafil's clearance.