Lemborexant overdose presenting with mild sedation despite high plasma levels: A case report.

Introduction: Lemborexant is a dual orexin receptor antagonist (DORA) with a favorable safety profile at therapeutic doses. However, clinical data regarding its toxic effects in overdose scenarios are limited. This is the first published case report of serially measured plasma concentrations of lemborexant in a patient who survived following acute overdose. Case report: A 33-year-old woman presented to the emergency department four hours after ingesting an estimated 720 mg of lemborexant and 78 mg of eszopiclone. She exhibited mild central nervous system depression (Glasgow Coma Scale score 11) but was hemodynamically stable. With supportive care alone, the patient's consciousness spontaneously improved. Retrospective analysis revealed that her plasma lemborexant concentration increased from 0.144 µg/mL at four hours to a peak of 1.410 µg/mL at nine hours post-ingestion, despite undergoing clinical recovery. Discussions: This case suggests that massive lemborexant overdoses may not cause life-threatening toxicity even when plasma levels approach those reported in fatal cases. This case provides preliminary but clinically important data and highlights the need for further research to better characterize the clinical implications and management of lemborexant overdoses.