Milrinone

Overview
Milrinone is a phosphodiesterase III inhibitor. It potentiates the effect of cyclic adenosine monophosphate (cAMP).

Milrinone 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.

Whereas beneficial hemodynamic effects are shown (at least short-term), several studies have shown no or a negative effect on mortality rates of hospitalized patients receiving milrinone.

One negative side to the use of milrinone is the prolonged half-life (2.5 hrs). This can result in a prolonged weaning and possible adverse outcomes from stopping this medication rapidly.