<prompt> Sildenafil acts by inhibiting?PDE 2PDE 5Adenyl cyclaseGaunyl cyclase  <response>: Sidenafil, verdenafil, tadalafil acts by inhibiting PDE5 they increase NO- increases blood supply to the penis making it erect But they can produce ceain cardiac events They are also used in Pul HTN Ref: KD tripathi 8th ed 