Editing Functional: Pharmacological Management of LUTS (section)

=== Phosphodiesterase Inhibitors ===
* '''Mechanism''': drugs acting through the nitric oxide (NO)/cGMP system, such as PDE5 inhibitors, can '''relax the smooth muscle of the bladder outflow region and may improve urinary bladder blood perfusion'''
* '''<span style="color:#ff0000">As monotherapy, PDE5 inhibitors significantly improve IPSS and International Index of Erectile Function (IIEF) scores, but not Qmax, when compared with placebo.</span>'''
** '''PDE inhibitors seem to improve subjective measurements but not objective ones, eg. Qmax'''
** '''The mechanism behind the beneficial effect of the PDE inhibitors on LUTS and OAB and their site(s) of action largely remain to be elucidated.'''
** Combination of PDE5 inhibitors and α-blockers led to significant improvements of the IPSS and IIEF scores as well as Qmax when compared with the use of α-blockers alone.
* As of the time of Campbell’s writing, only tadalafil has been approved for the treatment of LUTS caused by benign prostatic obstruction (BPO)
* There is insufficient information is available on the combination of PDE5 inhibitors with other LUTS medications such as 5α-reductase inhibitors.