title: Medication Error When Switching from Warfarin to Rivaroxaban Leading to Spontaneous Large Ecchymosis of the Abdominal and Chest Wall.
abstract: Non-vitamin K oral anticoagulant (NOAC) therapy may be inappropriate if prescription was incorrect, the patient's physiological parameters change, or interacting concomitant medications are erroneously added. The aim of this report was to illustrate inappropriate NOAC prescription in a 78-year-old woman with non-valvular atrial fibrillation and borderline renal dysfunction who was switched from warfarin to rivaroxaban and subsequently developed bruising with hemorrhagic shock and acute on chronic renal failure. Administration of 4-factor prothrombin complex concentrate effectively reversed coagulopathy and stopped bleeding. Retrospective determination of circulating plasma levels of rivaroxaban and warfarin confirmed that excessive anticoagulation was likely due to warfarin that the patient probably continued to take although rivaroxaban was initiated. Pharmacodynamic interaction between rivaroxaban and warfarin may not only be additive but synergistic. In patients at high risk of complications, judicious prescribing and dosing of NOACs, and regular monitoring of concomitant medications and renal function are highly recommended.
authors: Department of Internal Medicine, Central Hospital of Bolzano , BZ, Italy.
authors: Flavio
authors: F
authors: Egger
authors: Department of Clinical Pathology, Central Hospital of Bolzano , BZ, Italy.
authors: Federica
authors: F
authors: Targa
authors: Department of Internal Medicine, Central Hospital of Bolzano , BZ, Italy.
authors: Ivan
authors: I
authors: Unterholzner
authors: Center for Esoteric Testing, Laboratory Corporation of America® Holdings , Burlington, NC, USA.
authors: Russell P
authors: RP
authors: Grant
authors: Department of Clinical Pathology, Central Hospital of Bolzano , BZ, Italy.
authors: Markus
authors: M
authors: Herrmann
authors: Department of Internal Medicine, Central Hospital of Bolzano , BZ, Italy.
authors: Christian J
authors: CJ
authors: Wiedermann
keywords: Direct oral anticoagulants; anticoagulant reversal; drug safety; drug-drug interaction; pharmacovigilance; prothrombin complex concentrate; therapeutic drug monitoring