Anti-Xa activity in apixaban overdose: a case report

Introduction: Apixaban is a novel oral anticoagulation agent that exerts its effect through direct factor Xa inhibition. We present a case of multi-drug overdose including apixaban with associated apixaban concentrations.Case: A 53 year-old man presented to our metropolitan hospital following a deliberate self-poisoning with 200mg apixaban, 35mg ramipril, 105mg bisoprolol, 280mg atorvastatin, 6mg colchicine, 37.4mg magnesium, 4x500mg paracetamol/9.5mg codeine/5mg phenylephrine and alcohol. He developed hypotension that was treated with noradrenaline. His initial and peak apixaban concentration was 1022.6ng/ml and was associated with only minor bleeding from his femoral central line insertion site, which improved with local compression. Vitamin K 10mg (at 9h post-ingestion) and Prothrombinex-VF 2000 units (at 13h post-ingestion) were also administered without any observed effect on coagulation studies. Apixaban elimination appeared to display first-order kinetics with an elimination half-life of 7.4h. His plasma apixaban concentration was within the therapeutic dose range 10h post-ingestion and he recovered uneventfully.Conclusion: A case of apixaban overdose with associated apixaban concentrations is presented. There was rapid resolution of anticoagulation with no demonstrable benefit of currently available clotting factor replacement.