Take tadalafil exactly as directed. This information is reviewed by a licensed practitioner who will assess your eligibility for the medication. Nitrates come as tablets, sublingual under the tongue tablets, sprays, patches, pastes, and ointments. 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. It may be difficult to remain firm despite wanting to have sex. Cialis can last in the system for up to 36 hours.How to save on generic Cialis There are many ways to save on Cialis, which is available as both a brand-name and generic medication. Save with GoodRx. GoodRx can help you save over 97% off the average retail price of the generic version. Generic Cialis at certain pharmacies is less than $13 with a free GoodRx discount.  · The typical dose for once-daily Cialis for ED is milligrams (mg) to 5 mg. When used as needed for ED, the usual Cialis dose is 10 mg (with a maximum daily dose of 20 mg). The typical dose of. 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.