NCIt definition : A synthetic bipyridine phosphodiesterase inhibitor with inotropic and vasodilator
properties. Inamrinone inhibits type III phosphodiesterase, which is abundant in cardiac
and vascular tissues, thereby preventing the degradation of cyclic adenosine monophosphate
(cAMP) and increasing intracellular concentrations of this secondary messenger. Elevated
levels of cAMP increase the contractile force of the cardiac muscle and produce positive
inotropic effects. Although the mechanism of action is not fully understood, inamrinone
causes smooth muscle relaxation, resulting in peripheral vasodilation (reduced afterload)
and a decreased pulmonary vascular resistance (reduced preload).;