Activated charcoal can be used to aid the diagnosis of an overdose of dabigatran etexilate.

The direct-acting oral anticoagulant dabigatran etexilate (DE prevent systemic thromboembolism and cerebral apoplexy in patients with nonvalvular atrial fibrillation. On September 22, 2021, an 86-year-old female patient in Peking University People's Hospital presented with a severely reduced fibrinogen level and significantly prolonged prothrombin time (PT) and activated partial thromboplastin time (APTT). She had a history of hypertension, hyperlipidemia, arrhythmia, and a 1-year history of taking DE (110 mg, p.o., b.i.d.). She had no apparent bleeding tendency but had abnormalities in coagulation markers. She denied taking a DE overdose. Before deciding whether to transfuse plasma for replacement therapy, the attending physician wanted to ascertain if the abnormal results resulted from the drug or the abnormal coagulation mechanism of the patient. Tentatively, we used activated charcoal to treat plasma and then retested her coagulation markers: all coagulation tests nearly returned to normal levels. Hence, the cause was a DE overdose. Re-investigation revealed that she had lived alone in the previous week and possibly mistook the number of doses taken due to confusion. DE was withdrawn, and diuretics (Furosemide injection, 40 mg, QD2) were administered simultaneously to accelerate drug excretion. Five days after drug withdrawal, the coagulation tests returned to normal levels. This case report shows that activated charcoal could be used to show that the coagulation disorder was caused by a DE overdose, thereby providing support for the clinical diagnosis and treatment.