Erectile dysfunction, the inability to get or keep an erection during sexual activity, happens when the penile erection chambers fail to generate and maintain the high pressures that characterize a fully hard erection. Usually, sexual stimulation is enough to get things going, but men with ED have trouble staying firm through ejaculation. Lots of things can contribute, like age, high blood pressure, vascular disease, disease, stress, and more.

Yes, the good news is ED drugs, like sildenafil and tadalafil have been clinically proven to be effective treatments for ED. Both sildenafil and tadalafil are an oral tablet, that have been approved by the FDA to treat erectile dysfunction (ED). 

Sildenafil is in a group of medications called phosphodiesterase 5 (PDE5) inhibitors. Sildenafil treats ED by increasing blood flow to the penis during sexual stimulation, which leads to an erection. This medication comes in tablet form and is taken one hour before sexual activity. Sildenafil’s effects last 4-6 hours.

Tadalafil is in a group of medications called phosphodiesterase 5 (PDE5) inhibitors. It works by increasing blood flow to the penis during sexual stimulation. Tadalafil can be taken up to 36 hours before sexual activity and therefore is often known as the "weekender."

Although the effects of Tadalafil can help you achieve an erection for up to 36 hours, both Tadalafil and Sildenafil can be taken 1 hour before sexual activity. Maximum dose is 20mg for Tadalafil and 100mg for Sildenafil. Both medications should be taken with a full glass of water and can be taken on an empty stomach or with a normal sized meal. It's important to note that Sildenafil and Tadalafil will not give you an erection for the entire period that they are in your system. They simply allow you to achieve a satisfactory erection when you are sexually stimulated.