Tadalista Professional is a prescription drug used to treat erectile dysfunction. Tadalafil, the main active ingredient in the medication, dilates blood vessels to improve blood flow to the penis. Tadalafil, the active ingredient in Tadalista Professional, belongs to the group of drugs known as phosphodiesterase type 5 (PDE5) inhibitors and is present in an equivalent strength. It works by helping the penile blood arteries relax, allowing blood to flow into a man's penis during sexual activity. Using it more than once a day is not advised. About an hour before the patient intends to have sexual activity, one pill should be taken with a glass of water.