It affects the way the medicine works. John’s wort. To prevent stomach problems, have a small meal before or after you take Cialis. If you have erection problems, tadalafil works by temporarily increasing blood flow to the penis when you get sexually excited. You can only get it on prescription for erectile dysfunction if you have a specific condition such as multiple sclerosis or a spinal cord injury. If you have certain health conditions or are taking certain medications, your doctor may tell you to take tadalafil less often or may prescribe a lower dose to be taken once a day.CIALIS for once daily use is a lower dose you take every day. • Do not take CIALIS more than one time each day. • Take one CIALIS tablet every day at about the same time of day. You may attempt sexual activity at any time between doses. • If you miss a dose, you may take it when you remember but do not take more than one dose per day. 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. Roman is a telehealth prescription service and online pharmacy that provides prescription Cialis for ED and a host of other conditions, like hair loss, cold sores, and premature ejaculation. When.