Sildenafil citrate is a medication used for the treatment of erectile dysfunction (ED) in adult men. It is the active ingredient in the well-known brand name medication Viagra. Sildenafil citrate belongs to a class of drugs called phosphodiesterase type 5 (PDE5) inhibitors.

Erectile dysfunction is a condition characterized by the inability to achieve or maintain an erection sufficient for sexual activity. It can be caused by various factors, such as age, underlying health conditions, psychological factors, or lifestyle choices. Sildenafil citrate works by inhibiting the enzyme PDE5, which allows for increased blood flow to the penis, facilitating the ability to achieve and maintain an erection.