Direct oral anticoagulants (DOACs) are considered advantageous compared to vitamin K antagonists in eligible atrial fibrillation patients.1 Increased body weight is associated with 30% lower exposure to standard doses of DOACs, raising concerns about adequate dosing in obese patients.2,3 Due to lack of sufficient clinical data, use of DOACs in patients with a body mass index (BMI) > 40 kg/m² or a weight of >120 kg should be accompanied by measurement of trough and peak plasma concentrations.3