Efficacy of Low-Dose Ketamine and Propofol in the Treatment of Experimental Refractory Status Epilepticus on Male Rats

Abstract

Refractory status epilepticus (RSE) is a condition with serious mortality and morbidity rate, resistant to benzodiazepine and second-line antiepileptic drugs. This study aimed to electrophysiologically investigate the combination of NMDA receptor antagonist ketamine and GABAergic agent propofol in an RSE model induced by lithium-pilocarpine in male Sprague–Dawley rats. Seventy-two male Sprague–Dawley rats were divided into nine groups. The RSE model was induced by subcutaneous injection of lithium-CI (5 mEq/kg) and intraperitoneal injection of pilocarpine-HCl (320 mg/kg), after implanting tripolar EEG electrode. Ketamine (30, 60, and 90 mg/kg), propofol (20, 40, and 80 mg/kg), and combinations of both drugs (15 + 20 and 30 + 40 mg/kg) were administered intraperitoneally to animals with RSE. Video-EEG recordings were taken after inducing model and 48 h later. The efficacy of drugs was statistically evaluated based on spike frequencies (spikes/min) and amplitudes (mV). Compared to RSE group, it was determined that 30 and 60 mg/kg doses of ketamine provided effective seizure control and prevented mortality (p < 0.001), while the 90 mg/kg showed toxic effects in all animals and caused mortality. The 80 mg/kg dose of propofol provided seizure control and reduced the mortality rate to 16.7% (p < 0.001), whereas the 20 mg/kg resulted in a 100% mortality rate. The low-dose ketamine+propofol (15 + 20 mg/kg) combination provided early onset seizure control and were as effective as 80 mg/kg propofol (p < 0.05). The study concluded that in the experimental RSE model, seizure control could be achieved with low-dose combination of ketamine and propofol without the need for high doses as in monotherapy, thus preventing dose-related adverse effects.