Sildenafil is used for men with erection problems (erectile dysfunction). It works by increasing blood flow to the penis, to help achieve an erection. It will only work if you are sexually excited. Read more about erectile dysfunction.
Sildenafil belongs to a group of medicines called phosphodiesterase type-5 (PDE5) inhibitors. They help to make a penis erect. Read more about PDE5 inhibitors.