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 200 mg apixaban, 35 mg ramipril, 105 mg bisoprolol, 280 mg atorvastatin, 6 mg colchicine, 37.4 mg magnesium, 4 × 500 mg paracetamol/9.5 mg codeine/5 mg phenylephrine and alcohol. He developed hypotension that was treated with noradrenaline. His initial and peak apixaban concentration was 1022.6 ng/ml and was associated with only minor bleeding from his femoral central line insertion site, which improved with local compression. Vitamin K 10 mg (at 9 h post-ingestion) and Prothrombinex-VF 2000 units (at 13 h 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 7.4 h. His plasma apixaban concentration was within the therapeutic dose range 10 h 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.