Subsequently, the FDA approved both vardenafil [27] and tadalafil in The FDA has also approved tadalafil for treatment of both benign prostatic hypertrophy and erectile dysfunction where the two conditions co-exist. Tadalafil was approved in in the United States for the treatment of pulmonary arterial hypertension [28] and is under regulatory review in other regions for this condition. Mechanism of action[ edit ] Penile erection during sexual stimulation is caused by increased penile blood flow resulting from the relaxation of penile arteries and the smooth muscle of the corpus cavernosum. Equally, if you have any kind of heart condition, you need to be careful — medications for heart disease are often from the nitrate family, and those and Cialis do not mix well.tadalafil. erectile dysfunction (ED) benign prostatic hyperplasia, or BPH). Tadalafil (Cialis) is available both as brand-name and generic tablets. Common side . What is tadalafil? Tadalafil relaxes muscles of the blood vessels and increases blood flow to particular areas of the body. Tadalafil under the name of Cialis is . Cialis is a PDE5 inhibitor medication approved for use for erectile dysfunction (ED) and benign prostatic hyperplasia. Don’t take Cialis with nitrate class .