Store at room temperature away from moisture and heat. Use the medicine exactly as directed. Take Cialis just before sexual activity, but not more than once per day. Tadalafil treats PAH by relaxing the blood vessels in the lungs to allow blood to flow more easily. If you are taking tadalafil to treat erectile dysfunction, you should know that it does not cure erectile dysfunction or increase sexual desire.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. strength safety effectiveness stability quality Usually, generic drugs aren’t available until the expiration of the brand name’s patent. Eli Lilly and Company’s patent for Cialis expired in Pros lasts up to 36 hours for some people, which is longer than Viagra can be taken as needed or on a daily, regular basis daily use allows for a more spontaneous sex life can be taken with or.