Monitoring of Apixaban in a Super-Obese Patient: Impact of Renal Failure and Topical Application of Econazole

Direct oral anticoagulants (DOACs) are considered advantageouscompared with vitamin K antagonists in eligible atrial fibrillation patients, but the efficacyand the safety of DOACs are not well defined in the morbidly obese population.We report the case of a 59-year-old woman (160 cm, 188 kg, body mass index 73.5 kg/m²) with multiple comorbidities including non-valvular atrial fibrillation,who was anticoagulated with apixaban 5 mg twice a day and who was admitted to our hospitalbecause of acute renal failure.We report changes in apixaban concentrations over the course ofmanagement. Apixaban concentrations were quantified using Liquid Anti-XaHemosIL® Werfen. The table and figure show apixaban concentrations according totherapeutic modifications and renal function.This case illustrates the importance of occasionally measuring the DOACconcentration in the case of intercurrent pathology, in particular acute renal insufficiency,or in the case of topical use of drugs known to interact with DOACs by the oralroute. Plasma DOAC measurement would be also interesting in the case of co-medicationswith an unknown potential for drug interactions. This case also shows an effective and safeanticoagulation by DOAC in a super-obese patient.