Tadalafil, a phosphodiesterase type 5 inhibitor, is the active ingredient in the medicine Vidalista. It helps men achieve and sustain an erection by increasing blood flow to the penis, which is its major method of treating erectile dysfunction. Vidalista can be used to treat erectile dysfunction as needed, usually 30 to 60 minutes before intercourse. Because of its 36-hour duration of effect on sexual performance, Vidalista has been dubbed "The Weekend Pill." For instance, grapefruit and grapefruit juice should be avoided since they raise blood levels of tadalafil, which increases the chance of adverse effects.