PDE5A and benign prostatic hyperplasia: To date, a consensus has been reached that the potential mechanisms of PDE5-Is in treating LUTS/BPH are multifactorial28: (1) Slight-to-moderate relaxation of muscle tone in prostate and bladder; (2) Significant dilation of local blood vessels which provide adequate blood; (3) Significant augmentation of oxygen perfusion to local organs; (4) Inhibition of afferent nerve activity of bladder; (5) Bluntness of intraprostatic inflammation; (6) Antiproliferation in prostate.