Evaluation of levetiracetam loading dose in adult patients with benzodiazepine-refractory status epilepticus

Abstract

BackgroundStatus epilepticus (SE) is a neurologic emergency defined as continued seizure activity greater than five minutes or recurrent seizure activity without return to baseline. Benzodiazepine-refractory SE is continuous seizure activity despite treatment with a benzodiazepine. Treatment of benzodiazepine-refractory SE includes levetiracetam with loading doses ranging from 20 mg/kg to 60 mg/kg up to a maximum dose of 4500 mg. While levetiracetam has minimal adverse effects, there is currently a lack of studies directly comparing the safety and efficacy of various loading doses of levetiracetam. ObjectiveThe objective of this study was to evaluate the safety and efficacy of three loading doses of levetiracetam in the setting of benzodiazepine-refractory SE. MethodsThis was a single center, retrospective cohort study of adult patients with benzodiazepine-refractory SE who were treated with levetiracetam from April 1, 2016, to August 31, 2023. Patients with documented hypersensitivity to levetiracetam, those who were pregnant or incarcerated and patients who received an alternative antiepileptic drug (AED) prior to levetiracetam were excluded. Patients with other identifiable causes of SE including hyperglycemia, hypoglycemia, hyponatremia or who were post cardiac arrest were also excluded. Patients were divided into three arms based on loading dose of levetiracetam administered (≤20 mg/kg [LEVlow], 21‐–39 mg/kg [LEVmed] or ≥40 mg/kg [LEVhigh]). The primary endpoint was the rate of seizure termination, defined as the lack of need for an additional AED within 60 min following levetiracetam administration. Secondary outcomes included the rate of intubation, and recurrent seizure activity 60 min to 24 h post seizure termination as defined by positive EEG results or need for an additional AED. Subgroup analyses were performed to assess the influence of adequate loading doses of benzodiazepines, and outpatient levetiracetam use. ResultsOverall, 740 patients were screened for inclusion, with 218 patients being included in the primary analysis. Patients were divided into three groups with an average levetiracetam loading dose of 14.5 mg/kg in the LEVlow group, 28.8 mg/kg in the LEVmed group, and 48.8 mg/kg in the LEVhigh group. There was no difference in rates of seizure termination at 60 min (92.9% LEVlow vs 89.3% LEVmed vs 84.7% LEVhigh; p = 0.377). Additionally, no difference was found in rates of recurrent seizure activity between 60 min and 24 h post levetiracetam loading dose (32.1% LEVlow vs 32.0% LEVmed vs 28.8% LEVhigh; p = 0.899). However, the LEVhigh group did have a higher rate of intubation (45.8%) compared to the LEVmed (28.2%) and LEVlow (26.8%) group (p = 0.040). ConclusionThe loading of levetiracetam did not result in a statistically significant difference in rate of seizure termination at 60 min nor did it appear to impact the rate of recurrent seizures at 24 h. However, we did find higher rates of intubation in patients who received levetiracetam >40 mg/kg. Further research is warranted to determine the optimal loading dose of levetiracetam in benzodiazepine-refractory SE.