what is pde5 enzyme
All three are known as phosphodiesterase-5 (PDE5) inhibitors. By blocking the PDE-5 enzyme, these drugs help the smooth muscles of the penis to relax and increase blood flow. PDE5 inhibitors are generally the first choice of treatment for erectile dysfunction.y blocking the PDE-5 enzyme, these drugs help the smooth muscles of the penis to relax and increase blood flow. PDE5 inhibitors are generally the first choice of treatment for erectile dysfunction.