Drug sequestration and metabolite formation: key pharmacokinetic challenges for levosimendan use during ECMO support in cardiogenic shock

BACKGROUND: In patients with refractory cardiogenic shock, veno-arterial extracorporeal membrane oxygenation (ECMO) provides temporary circulatory support, but optimal strategies to promote myocardial recovery and facilitate ECMO weaning remain uncertain. Levosimendan is a calcium-sensitizing inotrope and vasodilator that improves cardiac performance and may support cardiac function and shorten the duration of ECMO support. DISCUSSION: The recent multicenter randomized placebo-controlled LEVOECMO trial demonstrated no benefit of early levosimendan infusion on ECMO weaning or clinical outcomes, providing robust evidence against routine and early use. Several pharmacokinetic factors may have attenuated levosimendan efficacy in this setting. Levosimendan is prone to sequestration within the ECMO circuit, particularly early after cannulation. Moreover, its short half life and its reliance on hepatic and intestinal metabolism for the generation of the long-acting active metabolite may limit its effectiveness during the early phase of cardiogenic shock, when high incidence of hepatic dysfunction and mesenteric hypoperfusion may contribute to reduced active metabolite production. In addition, renal replacement therapy is frequently required in ECMO patients and may further reduce plasma concentrations of active metabolites. Taken together, and in the absence of therapeutic drug monitoring, these factors may result in highly variable and unpredictable exposure to active metabolites among patients. These considerations raise the hypothesis that alternative strategies such as delayed initiation with therapeutic drug monitoring might improve exposure to levosimendan and its active metabolites. CONCLUSION: While recent evidence discourages routine early levosimendan use during ECMO for cardiogenic shock, a personalized, pharmacology-driven approach needs further investigation before a definitive conclusion.