Tadalafil comes as a tablet to take by mouth. Tadalafil is sometimes taken as needed, usually at least 30 minutes before sexual activity and not more often than once every 24 hours. If you are taking tadalafil to treat erectile dysfunction, follow your doctor’s directions and the guidelines in this paragraph. Cialis was also investigated in combination with finasteride, another BPH medication, in another trial. Ask your pharmacist or doctor for a copy of the manufacturer’s information for the patient. When the smaller blood vessels in the lungs become more resistant to blood flow, the right ventricle must work harder to pump enough blood through the lungs. For this purpose, one dose works for up to 72 hours.Tadalafil (Cialis) is used to treat erectile dysfunction (ED, impotence; inability to get or keep an erection), and the symptoms of benign prostatic hyperplasia (BPH; an enlarged .  · Cialis (tadalafil) is prescribed to treat erectile dysfunction and symptoms of benign prostatic hyperplasia. It comes as a tablet that’s taken as needed or once per . Cialis is a prescription medication containing the active ingredient tadalafil. Cialis belongs to a group of medications known as phosphodiesterase-5 (PDE-5) .