Taking a higher dose of sildenafil will increase your risk of experiencing side effects, including side effects that are potentially dangerous. Patients should never take more than 100 mg of sildenafil within 24 hours.Feb 5, 2021
Sildenafil (Viagra) for ED (erectile dysfunction) lasts about four hours. It reaches peak concentrations in about an hour, so it's best to take sildenafil 30 to 60 minutes before sex. While you can take it up to four hours beforehand, the effects will decrease after two hours or so.Feb 19, 2020
Never take more than 100 mg of Viagra in a 24-hour period. Too much Viagra can cause severe headache, low blood pressure, and orthostasis (drop in blood pressure when standing) that can lead to fainting. Higher doses can also cause priapism, a painful erection that lasts longer than 4 hours.