When used for pulmonary arterial hypertension, tadalafil should not be co-administered with potent CYP3A inhibitors. Caution should be exercised when administering sapropterin in combination with drugs that affect nitric oxide-mediated vasorelaxation such as phosphodiesterase inhibitors. See our source here What is Tadalafil? In theory, CYP3A4 inhibitors which may interact with tadalafil include ranolazine. Do not take more or less of it or take it more often than prescribed by your doctor. Keep tadalafil and all medicines out of the reach of children.Talk to your doctor about which dosing schedule is right for you. Tadalafil is sometimes taken as needed, usually at least 30 minutes before sexual activity and not more often .  · Adcirca Cialis Descriptions Tadalafil is used to treat men who have erectile dysfunction (also called sexual impotence). Tadalafil belongs to a group of medicines . Healthcare providers may also prescribe tadalafil to manage two other health conditions involving insufficient blood flow: pulmonary arterial hypertension (PAH) .