Furthermore, the longer half-life is the basis for tadalafil’s daily therapeutic use in treating pulmonary arterial hypertension. Ask them for medical advice if you have any concerns or need a guideline explained. BPH is caused by an enlarged prostate. There may be rare occurrences of priapism or painful, prolonged erections. FDA encourages anyone aware of a serious side effect, including consumers or patients, to make a MedWatch report.Some vendors market liquid versions of Cialis and other ED medications for sale online, usually labeled as “research chemicals.” These products aren’t .  · Cialis; Descriptions. Tadalafil is used to treat men who have erectile dysfunction (also called sexual impotence). Tadalafil belongs to a group of medicines . 1. What is Cialis used to treat? Cialis is approved for the treatment of men who experience difficulty having and maintaining an erection (impotence). 2. How does Cialis work? .