Inodilators are a class of medication used in acute heart failure and cardiogenic shock that combine positive inotropic effects that increases heart muscle contractility with systemic and pulmonary vasodilation.
By increasing cardiac output while simultaneously lowering vascular resistance, these agents help the heart pump more effectively with less effort.Key
The most common inodilators are milrinone, levosimendan, and to a lesser extent, dobutamine.
Inodilators often act as phosphodiesterase 3 (PDE3) inhibitors, increasing intracellular cyclic AMP, which boosts calcium influx for contraction and causes vascular smooth muscle relaxation.
Used in the intensive care unit (ICU) for acute decompensated heart failure, severe ventricular failure, or as temporary support for patients with low cardiac output.
These drugs improve oxygen delivery, support right ventricular function, and can reduce left ventricular filling pressures.
Potential side effects include hypotension due to excessive vasodilation and arrhythmias.
Types of Inodilators
PDE3 Inhibitors (e.g., Milrinone): Increase contractility and reduce preload and afterload.
Calcium Sensitizers (e.g., Levosimendan): Enhance contractility without a massive increase in intracellular calcium, while also opening ATP-sensitive potassium channels to cause vasodilation.
Sympathomimetic Agonists (e.g., Dobutamine): Act through beta-receptor stimulation.
Clinical Role
Inodilators are often used alongside or instead of pure vasopressors, like norepinephrine, in severe cardiogenic shock to maintain blood pressure and improve perfusion.
They are particularly effective when the patient has high systemic vascular resistance.