Amphotericin B Formulation Selection During Veno-Venous Extracorporeal Membrane Oxygenation: Two Case Reports Illustrating Clinical Dilemmas in the Absence of Data

Abstract

The use of amphotericin B (AmB) in patients requiring extracorporeal membrane oxygenation (ECMO) remains poorly characterized because of concerns about drug sequestration within the circuit, particularly with liposomal formulations. We describe 2 patients with life-threatening coccidioidomycosis who received different AmB formulations during veno-venous (VV) ECMO support. The first patient, a 23-year-old male with disseminated disease involving massive splenomegaly and multi-organ failure, received liposomal AmB at 5 mg/kg/day but died within 8 days of antifungal initiation due to progressive critical illness before treatment efficacy could be assessed. The second patient, a 37-year-old male with pulmonary disease, was transitioned from liposomal to conventional AmB at 1 mg/kg/day upon VV-ECMO initiation due to theoretical sequestration concerns and survived to hospital discharge, although he developed acute kidney injury potentially attributable to conventional AmB nephrotoxicity. These cases highlight medication use dilemmas associated with AmB formulation selection during VV-ECMO, including potential underexposure with liposomal formulations and nephrotoxicity with conventional AmB. Our experience highlights that formulation selection requires an individualized risk-benefit assessment that balances potential drug underexposure against nephrotoxicity in already vulnerable patients. These cases contribute to the limited literature on AmB use during ECMO but, more importantly, highlight the urgent need for systematic pharmacokinetic studies with therapeutic drug monitoring to transform clinical decision making from expert opinion to evidence-based practice.