Sildenafil citrate in Vigora 50 mg works by inhibiting the enzyme phosphodiesterase type 5 (PDE5), which regulates blood flow in the penis. By blocking PDE5, sildenafil allows for increased levels of cyclic guanosine monophosphate (cGMP), which relaxes smooth muscles in the blood vessels of the penis. This relaxation enables increased blood flow, facilitating an erection.

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