Sildenafil, which is found in Suhagra 100 sildenafil, belongs to a class of drugs known as phosphodiesterase type 5 (PDE5) inhibitors. It is used to treat erectile dysfunction, often known as impotence, in adult men. It occurs when a guy is unable to obtain or maintain a hard, erect penis that is suited for sexual engagement. Erectile dysfunction is defined as a man's inability to achieve and keep an erect penis stiff enough to facilitate sexual intercourse. This medication works by assisting in the relaxation of the blood vessels in the penis, allowing blood to flow into the penis when sexually stimulated. Sildenafil works by relaxing blood vessels, allowing more blood to flow into the penis while you're sexually stimulated.