Suhagra 100 mg (sildenafil citrate), Sold by the brand name Viagra among others, has a medication used to treat erectile dysfunction and pulmonary arterial hypertension. Sildenafil acts by blocking phosphodiesterase 5 (PDE5), an enzyme that can promote the breakdown of cGMP, which can regulate blood flow in the penis. It can require sexual arousal, however, to work. It can result in the spread of the blood vessels in the lungs. If you want to get more detail about ED and men's impotence then have a peek here: pharmev.com.