Tadalafil is a prescription drug used in treating erectile dysfunction (ED) and the symptoms of enlarged prostate in men. It is also indicated to treat pulmonary arterial hypertension (PAH). Tadalafil is one of the phosphodiesterase type 5 (PDE5) inhibitors. When these groups of drugs inhibit PDE5 they in turn enhance erectile function. Tadalafil can reduce the symptoms of enlarged prostate glands including urgent/frequent urination, difficulty in peeing, and urinary incontinence. It achieves this by relaxing the muscles in the prostate and bladder.