Pharmacokinetics of fondaparinux 1.5 mg once daily in a real-world cohort of patients with renal impairment undergoing major orthopaedic surgery

International audience; Purpose Fondaparinux, a selective activator factor X (factor Xa) inhibitor, is effective and safe for preventing venous thromboembolism after major orthopaedic surgery (MOS) at the once-daily subcutaneous dose of 2.5 mg. As the drug is mainly eliminated by the kidneys, a reduced dosage (1.5 mg once daily) was developed for patients with renal impairment. Methods We studied the pharmacokinetics (PK) of this dosage regimen using data from a real-world cohort of 442 patients with renal impairment (creatinine clearance 20-50 ml/min) undergoing MOS. Data were analysed using NON-linear Mixed Effect Modelling software (NONMEM) software. Fondaparinux PK was modelled using a two-compartment model with first-order absorption. Results This analysis confirmed the relationship between renal function and fondaparinux PK profiles. The mean predicted steady-state area under the plasma concentration time curve, peak and trough plasma concentrations of fondaparinux were lower by 15.6 %, 13.0 % and 10.3 %, respectively, in patients with renal impairment treated with 1.5 mg compared with patients with normal renal function treated with 2.5 mg (p Conclusion Although administration of 1.5 mg fondaparinux in patients with renal impairment resulted in a predicted exposure slightly lower than that achieved with 2.5 mg in patients with normal renal function, fondaparinux 1.5 mg is a valuable thromboprophylactic option in MOS patients with renal impairment who are at risk of bleeding.