Dabigatran overdose: case report of laboratory coagulation parameters and hemodialysis of an 85-year-old man.

Dabigatran is an oral direct inhibitor indicated for stroke prevention in patients with atrial fibrillation. Unlike warfarin, dabigatran's observed therapeutic window and minimal drug-to-drug interaction suggest that laboratory test and dose adjustments are not necessary; nevertheless, circumstances of excessive anticoagulation, decreased kidney function, and instances of significant bleeding and thrombosis require laboratory assessment. In order to gather experience in the management of global [activated partial thromboplastin time (APTT) and thrombin time (TT) with extended endpoint] and specific [ecarin chromogenic assay (ECA) and diluted thrombin time (dTT)] laboratory coagulation tests in patients receiving dabigatran with untoward effects, we describe a case in which hemodialysis was used in attempt to remove dabigatran in a patient with excessive anticoagulation, rectal bleeding, and severe anemia. Our experience confirmed that APTT is an unreliable method for the assessment of dabigatran in patients with acute complications because it was often normal in spite of the therapeutic drug plasma levels. Both ECA and dTT showed a linear correlation with dabigatran levels over a broad range, and identified therapeutic and supratherapeutic levels. TT assay, which is highly sensitive to dabigatran, correlated well and linearly not only with low drug levels, but also, because of the introduction of the extended endpoint (400 s), with high concentrations of the drug, and demonstrated to be a simple and reliable alternative to ECA and dTT to assess dabigatran in patients with acute complications.