Daily doses are often between 2. What should I do if I forget a dose? These include a heart attack, stroke or a serious heart rhythm disorder in the past six months. Emling S. A newer form of the medicine that dissolves on the tongue might work faster than the pill that you swallow. Talk with your healthcare provider about your sex life and desired use. · But on average, its effects start to lessen 2 to 3 hours after you take a dose. The typical dose for once-daily Cialis for ED is milligrams (mg) to 5 mg. When used as needed for ED, the usual. If you do buy medicines over the internet: Check to see if an online pharmacy is legitimate. Never order medicines from an online pharmacy that doesn’t list its phone number and . Can you legally buy Cialis online? Yes, it is legal to purchase Cialis online. However, people should only use reputable telehealth companies and online pharmacies.