Nadroparin Pharmacokinetics in Different Stages of COVID-19

Objective: The risk of thrombotic complications in critical COVID-19 patients remains extremely high, and multicenter trials failed to prove the survival benefit of escalated doses of low molecular weight heparins (LMWH) in this group. The aim of this study was to develop a pharmacokinetic model of LMWH (nadroparin calcium) according to different stages of COVID-19 severity. Design: The investigators performed a prospective observational study. Patients: Blood samples were obtained from 43 COVID-19 patients that received nadroparin and were treated with conventional oxygen therapy, mechanical ventilation, and extracorporeal membrane oxygenation. Setting: The investigators recorded clinical, biochemical, and hemodynamic variables during 72 hours of treatment. The analyzed data comprised 782 serum nadroparin concentrations and 219 anti-factor Xa levels. The investigators conducted population nonlinear mixed-effects modeling (NONMEM) and performed Monte Carlo simulations of the probability of target attainment (PTA) for reaching 0.2-0.5 IU/ml anti-Xa levels in study groups. Interventions: None. Measurements and Main Results: The investigators successfully developed a one-compartment model to describe the population pharmacokinetics of nadroparin in different stages of COVID-19. Conclusions: Different nadroparin dosing is required for patients undergoing mechanical ventilation and ECMO to achieve the same targets as those for non-critically ill patients.