How does Pfizer Viagra ® work?
Pfizer Viagra ® (sildenafil citrate) enables many men with erectile dysfunction (ED) to respond to sexual stimulation. When a man is sexually aroused, the arteries in the penis relax and widen, allowing more blood to flow into the penis. As the arteries in the penis expand and harden, the veins that normally carry blood away from the penis become compressed, restricting the blood flow out of the penis. With more blood flowing in and less flowing out, the penis enlarges, resulting in an erection. Please understand that sildenafil citrate is not a hormone or aphrodisiac, it works only when a man is sexually stimulated. See Diagram for more detail.
