Seizure Therapy With Intravenous Levetiracetam and Lorazepam

The overarching aim of STILL is assessment of IV LEV in the management of seizures in the ED setting. The main study endpoints are considered in the two patient groups of interest (SE and non-SE): * For non-SE patients, STILL will compare IV LEV vs. the current standard-care of placebo, with respect to the following questions: * Does IV LEV administration result in lower seizure duration and/or recurrence rate than does administration of placebo? (Ho: No difference in seizure duration or recurrence rates between the two groups.) * Is IV LEV associated with a different rate of significant side effects than placebo? (Ho: No difference in significant side effect rates between the two groups.) * For SE patients, STILL will compare \[IV LEV + lorazepam 2mg\] vs. \[lorazepam 3 mg\], with respect to the following questions: * Does addition of IV LEV to a BZD allow for a BZD-sparing effect (i.e. achievement of seizure control with lower dose of BZD)? (Ho: No difference in seizure duration and/or recurrence rates between the two groups.) * Is IV LEV + lower-dose BZD associated with a different rate of significant side effects than the higher-dose BZD administered as monotherapy? (Ho: No difference in significant side effect rates between the two groups.)