You could get dizzy, faint or have a heart attack or stroke. How will Cialis be supplied? You need a prescription from a doctor to buy tadalafil. Prolonged erections can be dangerous. If you are taking tadalafil to treat erectile dysfunction, you should know that it does not cure erectile dysfunction or increase sexual desire.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. Extra 15% off $30 sitewide with code SAVE15; Clip your mystery deal! BOGO 50% off select Walgreens health & wellness. The price you pay for generic Cialis also depends on your treatment plan, if you have insurance or are paying out of pocket, and in some cases, even the pharmacy you choose.