The active component in Fildena double 200, sildenafil citrate, is used to treat pulmonary arterial hypertension or erectile dysfunction (PAH). When sildenafil citrate transforms, it affects the hormone cGMP in your body. Nitric oxide starts to activate itself, which starts the process of vasodilation surrounding arteries. It aids in obtaining a solid erection by increasing blood flow to the penis for ED. You might get a hard erection since it increases the blood and oxygen flow to the penis.