Cialis is a commonly used medication for the treatment of erectile dysfunction (ED) and benign prostatic hyperplasia (BPH). It is also marketed under the brand name Adcirca for the treatment of pulmonary arterial hypertension (PAH). Cialis belongs to a class of drugs known as phosphodiesterase type 5 (PDE5) inhibitors, which work by increasing blood flow to the penis and relaxing the muscles in the walls of blood vessels. Cialis was first approved...