Erectile dysfunction medications require a prescription from a licensed provider. 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. What Is Cialis? You’ll also need to fill out a medical questionnaire with answers about your medical history, current medications, and lifestyle habits. It depends on the platform and insurance provider. If you are already taking medication to treat BPH, your doctor may tell you to stop taking your other medication at least one day before starting treatment with tadalafil.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. Side Effects. Headache, stomach upset, back pain, muscle pain, stuffy nose, flushing, or dizziness may occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly. To. Compare prices and print coupons for Cialis (Tadalafil (Cialis)) and other drugs at CVS, Walgreens, and other pharmacies. Prices start at $ See more.