Perfomedil is a vasodilator. Perfomedil is a buflomedil analog. Perfomedil like its parent compound buflomedil, antagonizes both alpha1- and alpha2-adrenoceptors. An important difference between perfomedil and its parent compound is the preferential antagonism exerted against alpha2-adrenoceptors. In the saphenous vein of the dog perfomedil acts as a relatively weak alpha-adrenergic blocker in vascular smooth muscle, with a preferential effect on postjunctional alpha2-adrenoceptors. At the adrenergic nerves, the compounds inhibit prejunctional alpha2-adrenoceptors and displace stored transmitter.