class="Serp__item__snippet--34vQF">Viagra, generic name Sildenafil citrate, is also a PDE5 inhibitor, similar to Cialis and also works in the same way. It protects cyclic guanosine monophosphate (cGMP) from degradation by cGMP-specific phosphodiesterase type 5 (PDE5) in the corpus cavernosum. It is...