The Potential of Bemegride as an Activation Agent in Electroencephalography in Dogs

SIMPLE SUMMARY: Electroencephalography is being increasingly recognized as invaluable in the diagnosis and management of epilepsy in veterinary medicine. However, the occurrence of seizures cannot be predicted, and abnormal findings are not always readily available at the time of examination. Activation methods are techniques that provoke interictal electroencephalogram abnormalities, such as epileptiform discharges (EDs), and are routinely used in clinical settings in human medicine. Only a few activation methods have been investigated in veterinary medicine, and their effectiveness remains controversial. Therefore, the present study investigated the potential of bemegride as a pharmacological activator in dogs. The obtained results demonstrated that bemegride activated interictal EDs under anesthesia in all dogs with epilepsy, seemingly at spontaneous irritative zones. The dose required for ED activation was significantly lower in dogs with epilepsy (median; 7.3 mg/kg) than in those without (median; 19.7 mg/kg) (p = 0.0294). Furthermore, there were no serious adverse effects, such as the induction of clinical seizures, associated with the administration of bemegride. Therefore, bemegride has potential as a safe and effective activation agent in dogs with epilepsy. The present results provide more options for the diagnosis and therapeutic planning of epilepsy, including presurgical evaluations, in dogs. ABSTRACT: The present study investigated the potential of bemegride as a pharmacological activation agent that elicits epileptiform discharges (EDs) in interictal electroencephalogram (EEG) recordings in dogs. Four laboratory dogs with idiopathic epilepsy and four without epilepsy were included. The dogs were anesthetized using sevoflurane during EEG recordings. Bemegride was administered intravenously and repeatedly until EDs were enhanced or induced, or until the maximum dose (20 mg/kg) had been administered. Bemegride activated EDs in all dogs with epilepsy. These EDs predominantly occurred in each dog’s spontaneous irritative zones, which were identified without the administration of bemegride. EDs occurred after the administration of bemegride in 50% of dogs without epilepsy. The dose required for activation was significantly lower in dogs with epilepsy (median; 7.3 mg/kg) than in those without (median; 19.7 mg/kg) (p = 0.0294). The only suspected adverse effect associated with the administration of bemegride was vomiting in two dogs after awakening from anesthesia. There were no other adverse effects, including seizures. The present results demonstrated the potential of bemegride as a safe and effective pharmacological activation agent of EDs in anesthetized dogs with epilepsy and provided more options for the diagnosis and therapeutic planning of epilepsy, including presurgical evaluations, in dogs.