Avanafil is a selective phosphodiesterase‑5 inhibitor for erectile dysfunction that boosts nitric‑oxide–cGMP signaling to relax corpus cavernosum smooth muscle, improving penile blood flow during sexual stimulation without increasing libido. It is known for a very fast onset and shorter duration within the class, aiding on‑demand use when timing flexibility is desired under clinician guidance. High PDE5 selectivity reduces off‑target effects relative to older agents, and counseling typically covers cardiovascular status, nitrate avoidance, and coordination with meals, alcohol, and other medicines to optimize reliability and safety in everyday scenarios.