Tadalafil is prescribed for benign prostatic hyperplasia, erectile dysfunction, and pulmonary arterial hypertension. Learn about side effects and more. Tadalafil 5 mg daily is FDA-approved to treat the symptoms of enlarged prostate, including difficulty urinating, weak stream, and frequent or urgent urination. It can treat BPH alone or in combination with ED. Tadalafil increases blood flow to particular areas of the body and is used to treat erectile dysfunction. Learn about side effects, interactions and indications. Learn about tadalafil (Cialis) usage and dosing. Read the latest news and reviews about the drug as well as potential side effects and popular alternatives. Tadalafil is used to treat men who have erectile dysfunction (also called sexual impotence). Tadalafil belongs to a group of medicines called phosphodiesterase 5 (PDE5) inhibitors. It works to treat erectile dysfunction by increasing blood flow to the penis during sexual stimulation. This increased blood flow can cause an erection. Tadalafil treats PAH by relaxing the blood vessels in the lungs to allow blood to flow more easily. Tadalafil belongs to a group of medicines, known as phosphodiesterase-5 (PDE-5) inhibitors, which are used to treat erectile dysfunction or pulmonary arterial hypertension. In this case, the dosage usually starts at 2.5 mg a day. If this daily dosage doesn’t work well enough to treat your ED, your doctor may increase it to 5 mg a day. Tadalafil (Erectile Dysfunction, Benign Prostatic Hyperplasia) reference guide for safe and effective use from the American Society of Health-System Pharmacists (AHFS DI). Dosage for ED and BPH For people who have ED and BPH (ED/BPH), the recommended starting dose of tadalafil is 5 mg. You’ll usually take this once daily. This is also the maximum recommended.