Sildenafil Citrate, a PDE5 Inhibitor included in Fildena, enhances erectile performance by boosting blood flow to the penis. It functions by preventing PDE5, an enzyme, from breaking down cyclic guanosine monophosphate (cGMP), a chemical that relaxes blood arteries. This inhibition makes it possible for the penis to get more blood, which strengthens the erection. But since Fildena 200 doesn't start sexual arousal on its own, it only functions when sexual stimulation is present.