Tadaflo is used to treat male erectile dysfunction (impotence) and pulmonary arterial hypertension (PAH) which is approved by the Food and Drug Administration of the USA. Part of the physiological process of erection involves the release of nitric oxide (NO) in the corpus cavernosum. Tadaflo activates the enzyme guanylate cyclase which results in increased levels of cyclic guanosine monophosphate (cGMP), leading to smooth muscle relaxation in the corpus cavernosum, resulting in an increased inflow of blood and an erection.