Tadalafil does not prevent pregnancy or the spread of sexually transmitted diseases such as human immunodeficiency virus HIV. What should I do if I forget a dose? Cialis is the brand name for the generic medicine tadalafil. Cialis As Needed will be prescribed in doses of 5 to 20 mg. Tadalafil treats PAH by relaxing the blood vessels in the lungs to allow blood to flow more easily. It works to treat erectile dysfunction by increasing blood flow to the penis during sexual stimulation. Ask the pharmacist at your local pharmacy to enter your BuzzRx savings card or Cialis coupons when you drop off your prescription at the pharmacy counter.Compare tadalafil prices, print discount coupons, find manufacturer promotions, copay cards and patient assistance programs. Cialis Coupons, Copay Cards and Rebates. Cialis offers may take the form of printable coupons, rebates, savings or copay cards, trial offers, or free samples. Certain offers may be printable from a site while others may require registration, completing a questionnaire, or obtaining a sample from a medical professional. A manufacturer coupon or copay card is not available for Cialis. However, GoodRx discounts are available to help make it more affordable. Tadalafil, the generic version of Cialis is available for about $9 for 30 tablets of the 5 mg strength. See more.