Cenforce 200mg made from one ingredient, sildenafil citrate, belongs to a class of drugs called phosphodiesterase inhibitors. Penile erection in men occurs when blood flow to the p*nis improves blood vessels and the volume of blood flowing out of the penis decreases. This high blood flow can cause an erection. Sildenafil citrate treats pulmonary arterial hypertension (PAH) by narrowing the blood vessels in the organ to provide regular blood flow. If you are taking Cenforce 200 Black pills to treat male impotence, keep in mind that they do not cure male impotence or erectile dysfunction.