Amrinone is a positive inotropic agent and selective phosphodiesterase 3 (PDE3) inhibitor used for the short-term, intravenous treatment of acute decompensated congestive heart failure.
It increases cardiac contractility and causes vasodilation, improving output while lowering pressure.
Medical Use and Indications
Acute Heart Failure: for the short-term management of acute decompensated heart failure.
As a PDE3 inhibitor, it increases intracellular cyclic adenosine monophosphate (cAMP) in myocytes, enhancing calcium release and contraction, while simultaneously relaxing vascular smooth muscle.
It boosts cardiac output, reduces pulmonary capillary wedge pressure, and reduces systemic vascular resistance.
Amrinone is associated with significant, though sometimes minimal, adverse effects, with its use often limited by its narrow therapeutic range.
Thrombocytopenia: A notable, often dose-dependent, decline in platelet count, occurring in about 10–30% of cases.
Cardiac Arrhythmias: High risk of arrhythmia.
Potential for hypotension, hepatotoxicity, fever, gastrointestinal disturbances (diarrhea, nausea), and severe injection site reactions.
No established benefit for long-term use and often leads to limiting side effects.
Interactions and Precautions
Often acts synergistically with other inotropes like catecholamines.
Drug Incompatibility: Direct, physical incompatibility exists with dextrose-containing solutions.
Continuous monitoring of blood pressure, heart rate, and platelet counts is required.
Amrinone has largely been replaced by other inotropic agents, though it was foundational in the development of modern cardiac care.