Sildenafil is a prescription medicine commonly used to treat erectile dysfunction (ED), a condition in which a man has difficulty achieving or maintaining an erection sufficient for sexual activity. It belongs to a group of medicines called phosphodiesterase type 5 (PDE5) inhibitors. While sildenafil is available in several strengths, including 25 mg, 50 mg, and 100 mg, 150 mg is higher than...