Use of Therapeutic Drug Monitoring to Personalize Antifungals for Blastomycosis in Pediatric Patients on Extracorporeal Membrane Oxygenation: A Case Series.

Amphotericin B and posaconazole are used in the treatment of pulmonary blastomycosis. Previous reports found inadequate treatment to both antifungals due to potential sequestration in extracorporeal membrane oxygenation (ECMO). There is a lack of evidence supporting routine use of therapeutic drug monitoring (TDM) with these agents. We report amphotericin B and posaconazole TDM in two separate cases of patients with pulmonary blastomycosis and on ECMO. Plasma concentrations were collected pre- and post-ECMO membranes and used to calculate pharmacokinetic and pharmacodynamic parameters. Drug sequestration within ECMO was not evident in our cases. As such, we speculate the drugs may have saturated the circuits over time. TDM of amphotericin B and posaconazole may be beneficial in pediatric patients on ECMO, especially near initiation of therapy or after a circuit change. Further studies are warranted to evaluate the relationship between plasma concentrations of these antifungals and efficacy and safety outcomes.