For CIALIS for use as needed, over and subjects were treated for at least 6 months and 1 year, respectively. Such an event may be a sign of non-arteritic anterior ischemic optic neuropathy NAION , a rare condition and a cause of decreased vision, including permanent loss of vision, that has been reported rarely postmarketing in temporal association with the use of all PDE5 inhibitors. It can also interact with many medicines, particularly nitrates used in some types of heart disease and blood pressure medicines. John’s wort. What special precautions should I follow?Tadalafil (Cialis) is a medicine used to treat erectile dysfunction (ED, also called impotence) and problems with urination caused by an enlarged prostate (benign prostatic hypertrophy or BPH). Tadalafil works by helping to relax the blood vessels in the penis, allowing blood to flow into the penis, and causing an erection. Cialis is a very popular and potent impotence treatment, based on the active ingredient tadalafil. / 5. Blanca Johnston. The majority of men will at some point struggle with attaining and maintaining aThe biggest difference between Viagra and Cialis is how long the drugs last in your system. Tadalafil, sold under the brand name Cialis among others, is a medication used to treat erectile dysfunction, benign prostatic hyperplasia, and pulmonary arterial hypertension. Tadalafil is an annulated 2,5-diketopiperazine. It is also a 1,2,3,4-tetrahydro-β-carboline.