Milrinone

Milrinone (Primacor) is a a potent and selective phosphodiesterase 3 inhibitor with an IC50 of 0.42 uM for the inhibition of FIII PDE. It potentiates the effect of cyclic adenosine monophosphate (cAMP). It also enhances relaxation of the left ventricle by increasing Ca2+-ATPase activity on the cardiac sarcoplasmic reticulum. This increases calcium ion uptake.It has positive inotropic, vasodilating and minimal chronotropic effects. It is used in the management of heart failure only when conventional treatment with vasodilators and diuretics has proven insufficient. This is due to the potentially fatal adverse effects of milrinone, including ventricular arrhythmias.