Viagra (sildenafil) belong to a group of medicines put off an enzyme called phosphodiesterase to work too quickly. Phosphodiesterase to control the erection sildenafil to help maintain production at the penis physical stimulation. We have all heard about the popularity of Viagra. In fact, the men at all ages, sexual young people to find new discoveries the little blue pill. However, any prescription drug, Viagra is not without its pitfalls and problems. RETTSUBAIAGURA take a closer look at.