ObjectiveTo investigate cost effectiveness of administration of flumazenil to patients presenting with suspected acute drug overdose.DesignDouble-blind, prospective, placebo-controlled randomized study.SettingUniversity teaching hospital.PatientsForty-three adults presenting with suspected drug overdose and having a Glasgow Coma Scale (GCS) score of <13. Patients with known benzodiazepine/tricyclic ingestion were excluded.InterventionsIntravenous administration of flumazenil (up to 2 mg) or placebo.Measurements and Main ResultsIndividual patient costs were assessed and data aggregated for each treatment group. Major diagnostic and therapeutic interventions were recorded and between group comparisons performed. Clinical response to study drug administration was assessed by obtaining pre- and post-drug GCS scores and observation of the patient for at least 180 mins for signs of resedation.Aggregate cost or number of major diagnostic and therapeutic interventions were not different between groups.Patients randomized to the flumazenil group showed a marked increase in GCS score (7.4 to 11.8) compared with those in the placebo group (8.2 to 8.6).ConclusionUse of flumazenil in intentional drug overdose of unknown etiology is not cost effective. (Crit Care Med 1999; 27:78-81)