Sildenafil citrate inhibits the enzyme PDE-5, leading to increased levels of cyclic guanosine monophosphate (cGMP). This, in turn, relaxes the smooth muscles in the blood vessels of the penis, allowing for increased blood flow.Vigora 50 mg is typically taken orally with a glass of water, approximately 30 minutes to an hour before sexual activity. The recommended dosage and usage instructions should be followed as prescribed by a healthcare professional.