Counterfeit medicines can be very dangerous. Tadalafil may not be safe for people with certain medical conditions, including people who have had a stroke , have coronary heart disease or retinitis pigmentosa an eye disease. If you are taking tadalafil on a regular schedule, take it at around the same time every day. Check the healthdirect’s medicines section for more information about tadalafil. How should this medicine be used? What special precautions should I follow? It affects the way the medicine works.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. MNT ‘s review. Lemonaid sells Cialis in these forms: Cialis: available in doses of 5, 10, and 20 mg, starting at $65 per tablet. Daily Cialis: 5 mg tablet with pricing starting from $50 per tablet. CIALIS for Use as Needed. Creatinine clearance 30 to 50 mL/min: A starting dose of 5 mg not more than once per day is recommended, and the maximum dose is 10 mg not more than once in every 48 hours. Creatinine clearance less than 30 mL/min or on hemodialysis: The maximum dose is 5 mg not more than once in every 72 hours [see .