Inamrinone (Amrinone) is a positive inotropic cardiotonic with vasodilator properties, phosphodiesterase inhibitory activity, and the ability to stimulate calcium ion influx into the cardiac cell. Inamrinone is a phosphodiesterase inhibitor (PDE3), resulting in increased cAMP and cGMP which leads to an increase in the calcium influx like that caused by beta-agonists resulting in increased inotropic effect. Inamrinone is used in the treatment of congestive heart failure.