sildenafil is a medication primarily used to treat erectile dysfunction in men. It works by increasing blood flow to the penis, helping to achieve and maintain an erection when sexually stimulated. This medication is often taken about 30 minutes to an hour before sexual activity and its effects can last for several hours. In addition to erectile dysfunction, sildenafil is also prescribed for pulmonary arterial hypertension, a condition that causes high blood pressure in the lungs. By relaxing blood vessels in the lungs, it helps improve exercise capacity and overall quality of life for those affected by this condition.