What is the comparison between dobutamine and milrinone?

From the Guidelines

Dobutamine and milrinone should be used with caution in acute heart failure, with dobutamine preferred in patients with hypotension and milrinone in those with significant beta-blocker use, as evidenced by the most recent guidelines 1.

Key Considerations

• Dobutamine is a synthetic catecholamine that stimulates beta-1 receptors, increasing cardiac contractility and output, typically administered at 2.5-20 mcg/kg/minute 1.
• Milrinone is a phosphodiesterase-3 inhibitor that increases cardiac contractility and causes peripheral vasodilation, usually given as a loading dose of 50 mcg/kg over 10 minutes, followed by a maintenance infusion of 0.375-0.75 mcg/kg/minute 1.
• Both medications require continuous cardiac monitoring and frequent assessment of blood pressure, heart rate, and clinical response 1.
• The choice of inotropic agent should be based on individual patient characteristics, such as the presence of beta-blocker use or hypotension, and the potential for adverse effects 1.

Adverse Effects and Special Considerations

• Dobutamine may cause tachyarrhythmias, hypertension, and nausea, while milrinone may cause thrombocytopenia and hypotension 1.
• Renal function should be monitored with milrinone as it's eliminated by the kidneys, and dose adjustments may be necessary in renal impairment 1.
• The development of tachyphylaxis should be acknowledged, and the choice of agent may need to be changed during longer periods of support 1.

Clinical Context

• The use of inotropic agents should be guided by the underlying cause of heart failure and the patient's individual needs, with a focus on minimizing adverse effects and optimizing clinical outcomes 1.
• The latest recommendations suggest an objective of 65 mmHg of mean blood pressure in cardiogenic shock patients 1.

From the FDA Drug Label

Milrinone lactate is a positive inotrope and vasodilator, with little chronotropic activity different in structure and mode of action from either the digitalis glycosides or catecholamines Dobutamine is a direct-acting inotropic agent whose primary activity results from stimulation of the β receptors of the heart while producing comparatively mild chronotropic, hypertensive, arrhythmogenic, and vasodilative effects.

The two drugs, milrinone and dobutamine, have different mechanisms of action.

• Milrinone is a phosphodiesterase inhibitor with inotropic and vasodilatory effects.
• Dobutamine is a beta-adrenergic agonist with inotropic effects. There is no direct comparison of the two drugs in the provided labels 2 3.

From the Research

Comparison of Dobutamine and Milrinone

• Dobutamine and milrinone are both used in the treatment of acute congestive heart failure and cardiogenic shock, with studies comparing their efficacy and safety profiles 4, 5, 6, 7, 8.
• A study published in 1996 found that milrinone and dobutamine both improved cardiac index, mean pulmonary capillary wedge pressure, and other hemodynamic parameters in patients with congestive heart failure following acute myocardial infarction, but milrinone was more effective in reducing pulmonary congestion 4.
• Another study published in 1986 compared the effects of milrinone, dobutamine, and nitroprusside on hemodynamics and myocardial energetics in patients with severe congestive heart failure, and found that all three agents increased cardiac index, but milrinone and nitroprusside caused a significant fall in pulmonary capillary wedge pressure without increasing heart rate or myocardial oxygen consumption 5.
• A meta-analysis published in 2023 compared the efficacy of dobutamine versus milrinone in acute decompensated heart failure and cardiogenic shock, and found that milrinone was associated with a lower risk of mortality in patients with acute decompensated heart failure, but there was no difference between the two agents in terms of acute kidney injury, initiation of renal replacement therapy, mechanical ventilation, arrhythmias, symptomatic hypotension, and length of hospital stay 6.
• A study published in 1986 found that milrinone and dobutamine similarly increased cardiac index in patients with severe congestive heart failure, but milrinone decreased left ventricular end-diastolic pressure to a greater extent and reduced mean systemic arterial and right atrial pressures, whereas dobutamine increased myocardial oxygen consumption 7.
• A retrospective review published in 2019 compared the effectiveness and safety of milrinone or dobutamine as initial inotrope therapy in cardiogenic shock, and found that both agents had similar effectiveness and safety profiles, but with differences in adverse events, such as arrhythmias and hypotension 8.

Hemodynamic Effects

• Both dobutamine and milrinone increase cardiac index and reduce pulmonary capillary wedge pressure, but milrinone may be more effective in reducing pulmonary congestion 4, 5.
• Milrinone decreases left ventricular end-diastolic pressure and reduces mean systemic arterial and right atrial pressures, whereas dobutamine increases myocardial oxygen consumption 7.

Safety Profile

• Arrhythmias are more common with dobutamine than milrinone, whereas hypotension occurs to a similar extent with both agents 8.
• Milrinone is more commonly discontinued due to hypotension, whereas dobutamine is more commonly discontinued due to arrhythmia 8.