Finally, while the review aimed to explore inflammatory effects in humans, there was some variation in the primary indication for PDE5 inhibitor treatment (e.g., erectile dysfunction, pulmonary hypertension, cystic fibrosis, benign prostatic hyperplasia), which introduces potential confounding factors, as the pathophysiology, inflammatory pathways, and clinical contexts differ across these conditions, making appropriate interpretation harder. This evidence concerns the gene PDE5A and erectile dysfunction.