It can also interact with many medicines, particularly nitrates used in some types of heart disease and blood pressure medicines. Tadalafil is in a class of medications called phosphodiesterase PDE inhibitors. What special dietary instructions should I follow? What should I talk to my doctor about when considering if Cialis is right for me? Follow your doctor’s directions carefully, and ask your doctor or pharmacist to explain any part you do not understand.Tadalafil 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). It is sometimes known by its generic name tadalafil, and sometimes known by its trade name, Cialis. There are also other brands of this medicine available. 4 rows · Both treatment options are available in doses of 5, 10, and 20 mg. The costs are: Cialis: A. Side Effects, Cost & More expand_more_outlined. Drug Info: Basics, Side Effects, Dosage & More. tadalafil. Generic Cialis. In clinical studies, people who took the 20 mg dose of tadalafil (Cialis) experienced an average drop in blood pressure by about 2 mm Hg. Most people won’t experience any noticeable symptoms from this blood .