비아그라 - 개요

If the cGMP is wrecked from the phosphodiesterase-five enzyme, the erection ends. Viagra helps prevent phosphodiesterase-five from destroying cGMP so cGMP stays around for a longer period, which ends up in a more extended erection. Should you expertise a painful erection or an erection that lasts lengthier than 4 several hours, get crisis treatmen