Eriacta 100 Mg is a generic version of Viagra, and it is often used as a more affordable alternative to the branded medication. Sildenafil Citrate, the active ingredient in Eriacta, belongs to a class of medications called PDE5 inhibitors. These drugs work by blocking the action of an enzyme called phosphodiesterase type 5 (PDE5), which plays a role in reducing blood flow to the penis. By inhibiting this enzyme, Sildenafil helps to relax blood vessels, thus increasing blood flow to the genital area, which is essential for an erection.