It affects the way the medicine works. Physicians should discuss with patients the potential for CIALIS to augment the blood-pressure-lowering effect of alpha-blockers and antihypertensive medications. To prevent stomach problems, have a small meal before or after you take Cialis. Tadalafil is in a class of medications called phosphodiesterase PDE inhibitors. It’s also sometimes used to treat pulmonary hypertension high blood pressure in the blood vessels that supply the lungs. If you become pregnant while taking tadalafil, call your doctor. Most erectile dysfunction medications belong to the drug class known as PDE5 inhibitors , which help relax the muscles and increase blood flow to allow for a full erection.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 prostate) which include difficulty urinating (hesitation, dribbling, weak stream, and incomplete bladder emptying), painful urination, and urinary frequency and urgency in adult men. About tadalafil Brand names: Cialis, Adcirca. About tadalafil. Tadalafil is a medicine used to treat erection problems (erectile dysfunction) and symptoms of an enlarged prostate (benign prostate enlargement). It’s also sometimes used to treat pulmonary hypertension (high blood pressure in the blood vessels that supply the lungs). Tadalafil (Cialis) is a medicine used to treat erectile dysfunction (ED, also called impotence) and problems with urination caused by an enlarged prostate (benign prostatic hypertrophy or BPH). Tadalafil works by helping to relax the blood vessels in the penis, allowing blood to flow into the penis, and causing an erection.