What is the use of Milrinone (Amrinone)?

From the Guidelines

Milrinone should be used with caution in patients with acute decompensated heart failure and cardiogenic shock, with a typical dosing of 50 mcg/kg loading dose administered intravenously over 10 minutes, followed by a continuous infusion of 0.375-0.75 mcg/kg/minute, as recommended by the most recent guidelines 1. The medication works by inhibiting phosphodiesterase-3 (PDE3), which increases intracellular cyclic adenosine monophosphate (cAMP) in cardiac and vascular smooth muscle cells. Some key points to consider when using milrinone include:

• The elevated cAMP levels enhance cardiac contractility while simultaneously causing peripheral vasodilation, which reduces both preload and afterload.
• Unlike traditional inotropes, milrinone improves cardiac output without significantly increasing myocardial oxygen demand or heart rate.
• Common side effects include hypotension, arrhythmias, and thrombocytopenia.
• Milrinone requires dose adjustment in patients with renal impairment as it is primarily excreted by the kidneys.
• Continuous hemodynamic monitoring is essential during administration, and the drug should be used cautiously in patients with severe aortic or pulmonic valvular disease due to its vasodilatory effects, as noted in previous studies 1. However, the most recent study 1 provides the most up-to-date guidance on the use of milrinone in clinical practice.

From the FDA Drug Label

INDICATIONS AND USAGE Milrinone Lactate Injection is indicated for the short-term intravenous treatment of patients with acute decompensated heart failure. The main use of Milrinone is for the short-term intravenous treatment of patients with acute decompensated heart failure 2.

• Key points:
  • Indication: acute decompensated heart failure
  • Administration: short-term intravenous treatment
  • Monitoring: patients should be observed closely with appropriate electrocardiographic equipment

From the Research

Milrinone Overview

• Milrinone is a phosphodiesterase 3 inhibitor with both positive inotropic and vasodilator properties 3.
• It is used in the treatment of acute decompensated heart failure and can be employed as a home infusion therapy or a bridge to cardiac transplant 4.

Clinical Use

• Milrinone is indicated for the short-term treatment of patients with acute decompensated heart failure 3.
• It can be used as a continuous infusion in pediatric outpatients as a treatment for cardiac dysfunction, as a destination therapy for cardiac transplant, or as palliative therapy for cardiomyopathy 3.
• Milrinone is also used in adults with congestive heart failure, although data supporting long-term therapy is limited 3.

Efficacy and Safety

• The use of milrinone has been associated with risks such as hypotension, atrial and ventricular arrhythmias, and possibly increased postdischarge mortality, particularly in those with coronary artery disease 5.
• Studies have shown that milrinone may have a bidirectional effect based on etiology in decompensated heart failure, being potentially deleterious in ischemic heart failure but neutral to beneficial in nonischemic cardiomyopathy 6.
• Comparison with other agents, such as nesiritide, has shown that milrinone may have similar or worse outcomes in terms of length of stay and readmission rates 7.

Dosage and Administration

• Concerns about adverse effects often limit the doses of milrinone used in clinical practice, and there is a need for comprehensive studies to guide milrinone dosing 4.
• Milrinone is primarily cleared by renal excretion, and its use is often avoided or limited in patients with acute renal failure or end-stage renal disease 4.