The perils of inhibiting deficient factors.
Essentials Anticoagulation in patients with factor X deficiency is an evidence-poor area. A patient with factor X deficiency was anticoagulated with warfarin followed by rivaroxaban. Warfarin may be a safer anticoagulant option than rivaroxaban in hereditary factor X deficiency. A baseline coagulation screen should be performed prior to commencement of anticoagulation.


SUMMARY
We report a case of a previously undiagnosed factor X deficiency in an 83-year-old man who had no previous bleeding history despite multiple hemostatic challenges. He was anticoagulated with warfarin for atrial fibrillation without bleeding complications; however, major hemorrhage occurred soon after a switch to rivaroxaban.
['Sayar|Z|Z|http://orcid.org/0000-0001-8838-9257', 'Speed|V|V|', 'Patel|J P|JP|http://orcid.org/0000-0003-4197-8294', 'Patel|R K|RK|', 'Arya|R|R|']
factor X rivaroxaban coagulation oral anticaogulants pharmacotherapeutics