Zolpidem-induced arousal by paradoxical gabaergic stimulation: A case report with F-18 flumazenil positron emission tomography and single photon emission computed tomography study

Zolpidem is a non-benzodiazepine drug that has selectivity for the gamma-aminobutyric acid (GABA) receptors. We experienced paradoxical effect of zolpidem in a 48-year-old male patient with hypoxic-ischemic brain injury after cardiac arrest. The patient was in stupor and could not communicate. His Glasgow Coma Scale (GCS) was E2M4V2 and Rancho Los Amigos (RLA) was grade III to IV. Zolpidem was prescribed to induce sedation but paradoxically, he became alert (GCS 15, RLA VII) and was able to communicate. The arousal lasted for 2 hours repeatedly following each administration of the medication. While he was alert, electroencephalogram showed the reversal of slow wave into beta range fast activity and F-18 flumazenil positron emission tomography (PET) showed increased GABAergic receptor activity in both frontoparietotemporal cortices. Single photon emission computed tomography (SPECT) also showed increased cerebral perfusion and reversal of cerebellar diaschisis.