Abstract

Dexamethasone (DEX) is currently the treatment of choice for patients with oxygen‐dependent COVID‐19. It has been observed, primarily in vitro , that dexamethasone induces the expression of CYP3A and the ABCB1 gene, which encodes P‐glycoprotein (P‐gp). This has raised concerns about potential interactions between DEX and substrates of CYP3A and P‐gp, such as direct oral anticoagulants (DOAC). Currently, there is limited robust evidence to support a clinically significant interaction between DEX and DOAC. Using physiologically based pharmacokinetic modeling (PBPK), we investigated the impact of DEX administered in the context of SARS‐CoV‐2 infection on the pharmacokinetics of apixaban (APX) and rivaroxaban (RVX). After validating the induction effect of the DEX compound on two CYP3A4 substrates using the limited available studies, we optimized the compound in a COVID‐19 patient population, where significantly higher DEX plasma concentrations were observed compared to healthy volunteers. Our PBPK‐based PK simulations showed a 20% decrease in the AUC of APX and RVX in a worst‐case scenario and when DEX was administered at 6 mg PO for 10 days. This finding confirms the limited clinical data currently available and supports the use of APX and RVX with DEX in COVID‐19 patients at low‐risk for thrombo‐embolism. In addition, our results suggest that prednisone (PRED), when used at an equipotent dose, could serve as a viable alternative to DEX, given its less pronounced induction effect on APX and RVX. Further research is needed to validate these findings and to explore the clinical implications of using PRED in place of DEX in such scenarios.