Considerations of safety for women prescribed apixaban or rivaroxaban who breastfeed—a physiologically based pharmacokinetic analysis

BACKGROUND: The risk of venous thromboembolism is significantly increased during the perinatal period. The safety of the direct oral anticoagulants, apixaban and rivaroxaban, has not been established in women who breastfeed. Physiologically based pharmacokinetic (PBPK) modeling provides a means to understand drug disposition and is increasingly being used to predict infant exposure to maternal medication via breastmilk. OBJECTIVES: To utilize established PBPK models of apixaban and rivaroxaban to simulate infant exposure to maternal ingestion. METHODS: Existing PBPK models for apixaban and rivaroxaban were adapted to the lactation setting. These models were verified using published reports of apixaban and rivaroxaban from breastfeeding women. A virtual postpartum population was then generated to simulate maternal and infant exposure to rivaroxaban and apixaban at different doses and time points during the postpartum period. Work was conducted on Simcyp Simulator (v23). RESULTS: was 2041 (±466) ng/mL. Maternal exposure to apixaban and rivaroxaban was lower immediately postdelivery and then normalized by 6 weeks postpartum. CONCLUSION: Our work demonstrates that apixaban would not be a suitable agent for breastfeeding women during the postnatal period, while rivaroxaban shows significant promise due to low infant exposure and warrants further investigation.