How fast does sildenafil work the main component of Viagra is Sildenafil Citrate. Sildenafil Citrate affects the response to sexual stimulation. It acts by enhancing smooth muscle relaxation using nitric oxide, a chemical that is normally released in response to sexual stimulation. This smooth muscle relaxation allows increased blood flow into certain areas of the penis, which leads to an erection. Sildenafil Citrate is applied for the treatment of erectile dysfunction (impotence) in men and pulmonary arterial hypertension. Sildenafil Citrate may also be used for other purposes not listed above. Inform your doctor if you have hypotension or hypertension, cardiac failure, coronary artery disease, deformations of the penis, sickle-cell anaemia, multiple myeloma, leukaemia, retinitis pigmentosa, and also a history of cardiac dysfunction, myocardial infarction, stroke arrhythmia, life-threatening arrhythmia, cardiovascular problems, allergies. Do not take Super P-Force together with other ED medication. If you think you have used too much of this medicine seek emergency medical attention right away. The symptoms of overdose usually include chest pain, nausea, irregular heartbeat, and feeling light-headed or fainting.