Sildenafil is an oral prescription drug used to treat erectile dysfunction (ED) and in some cases pulmonary arterial hypertension (PAH). This medicine is used to relax the blood vessels, improving the flow of blood to certain parts of the body. In the case of erectile dysfunction, sildenafil assists in achieving and maintaining an erection when sexual stimulation occurs. Since there may be interactions between sildenafil and other medications, such as nitrate drugs, patients must use this drug under the direction of a healthcare provider. Medszee offers informative material on prescription drugs, such as approved uses, possible side effects, precautions, and medication usage.