Levetiracetam in toxic seizures

Background/Objectives: The use of levetiracetam (LEV) in the management of drug-induced seizures has not been systematically investigated. Repetitive and continuous seizures that do not respond to benzodiazepines require second line therapy. Levetiracetam has a unique receptor binding site, rapid absorption, no known cardiac effects at therapeutic doses, and is theoretically a good candidate for use in drug-induced seizures. We evaluate the safety of LEV and its association with seizure cessation in this retrospective chart review of patients who received LEV as a control agent in drug-induced seizures. Methods: We identified the medical records of patients presenting to an urban, level 1 trauma center between 1 January 2010 and 31 May 2015 by ICD-9 codes based on the following: (1) a poisoning diagnosis, (2) a seizure diagnosis, and (3) administration of LEV. We included patients with a drug-induced seizure based on history, electroencephalogram results, blood alcohol concentrations, urine drug screens, and adequate documentation. We excluded patients with alcohol withdrawal, anoxic brain injury, subtherapeutic concentrations of other antiepileptics, hypoglycemia, and pseudoseizures. Primary outcomes of interest included cessation of active seizures or the prevention of seizure recurrence. We assessed safety by the presence or absence of adverse drug effects (ADE) attributed to the administration of LEV. Results: Thirty-four patients met inclusion and exclusion criteria. Half of the study cohort (17) presented with generalized tonic-clonic seizures (TCS); half (17) presented in generalized convulsive status epilepticus (GCSE). Six patients in GCSE received LEV during their seizures; 2 also received fosphenytoin. One improved immediately following LEV administration, and the remaining 5 had seizure control. Eleven GCSE patients (65%) remained seizure free after LEV therapy. The patients with TCS (17) received LEV after seizure(s) control. Sixteen (94%) were seizure-free during their hospital course. We found no adverse drug effects. In total, 27 of 34 patients (79%) had a return to baseline neurological and physical health. Six had long-term sequelae; none of which are known LEV side-effects. We identified 46 toxic substances and 22 known seizurogenic agents (48%). The median length of stay was 3.7 days (0.4-96), and the median duration of in-hospital LEV therapy was 1.6 days (0-49). Conclusions: Levetiracetam used as a second-line agent was associated with control of drug-induced seizures and prevention of seizure recurrence without obvious adverse effects. A prospective study is needed to confirm these results.