What important information should you know about Cialis? A newer form of the medicine that dissolves on the tongue might work faster than the pill that you swallow. Patients should seek prompt medical attention if their erection lasts longer than four hours. However, there was a long way to that recognition. In fact, the presence of any difficulties with getting and maintaining an erection may signal some more serious health issues like coronary artery disease, diabetes mellitus, atherosclerosis, and a wide range of other physical health problems. It lasts 4 to 5 hours, or longer if you have mild to moderate ED. There may be rare occurrences of priapism or painful, prolonged erections.stockcam / Getty Images What is generic Cialis? Generic Cialis is called tadalafil, which is the active ingredient in Cialis. Cialis is Food and Drug Administration Missing: australia. The four main medicines taken by mouth for erectile dysfunction are: Avanafil (Stendra). Sildenafil (Viagra). Tadalafil (Cialis). Vardenafil. These medicines are called PDE5 inhibitors. They enhance the effects of a chemical the body makes that relaxes muscles in the penis, called nitric oxide. headache. indigestion. back pain. muscle pain. flushing. stuffy nose. Patients who get back pain and muscle aches usually get them 12 to 24 hours after taking Cialis and these usually go away by.