The active component of Cenforce 200mg pills, which are prescribed to treat erectile dysfunction in men, is sildenafil, a phosphodiesterase type 5 inhibitor. The guanylate cyclase enzyme is activated by nitric oxide released by the penis' erectile tissue during sexual stimulation. This enzyme increases cyclic guanosine monophosphate (cGMP), which relaxes the penis's blood arteries and allows blood to enter the spongy erectile tissues, resulting in an erection.
When phosphodiesterase type 5 (PDE5), another enzyme, breaks down cGMP and limits blood supply to the penis, an erection is over.