If you are a Mayo Clinic patient, this could include protected health information. This medicine comes with a patient information leaflet. Taking Cialis does not mean you are guaranteed to get an erection. If you drink a large amount of alcohol more than five glasses of wine or five shots of whiskey while you are taking tadalafil you are more likely to experience certain side effects of tadalafil such as dizziness, headache, fast heartbeat, and low blood pressure. Sorry something went wrong with your subscription Please, try again in a couple of minutes Retry. Before taking tadalafil, tell your doctor and pharmacist if you are allergic to tadalafil, any other medications, or any of the ingredients in tadalafil tablets. · Tadalafil is used to treat men who have erectile dysfunction (also called sexual impotence). Tadalafil belongs to a group of medicines called phosphodiesterase 5 (PDE5) inhibitors. These medicines prevent an enzyme called phosphodiesterase type-5 from working too quickly. The penis is one of the areas where this enzyme works. Cialis is taken as an oral tablet, either as a low dose daily medication or as a higher-dose “on-demand” medication. It is the brand name for tadalafil, a medication . 5 mg orally once a day at approximately the same time, without regard to timing of sexual activity; Use: Treatment of the signs and symptoms of benign prostatic hyperplasia (BPH) Renal Dose Adjustments. Use as needed for ED: CrCl 30 to 50 mL/min: 5 mg orally once a day. The maximum dose is 10 mg not more than once in every 48 .