Take the pill with water, and if you like, you can eat it with a bit of food too. What special precautions should I follow? A few over-the-counter remedies that people sometimes explore include: DHEA. You won’t be able to find tadalafil over-the-counter in Canada. The drug works by increasing blood flow to the penis, thus aiding in achieving an erection.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. The most commonly reported side effects in patients treated with Cialis during the testing of the product were: headache. indigestion. back pain. muscle pain. flushing. stuffy nose. Patients who. Cialis comes in several different strengths, including: milligrams (mg) 5 mg. 10 mg. 20 mg. The cost for these different strengths depends on whether you have insurance, your individual plan.