OBJECTIVE: Nonsedating antiepileptic drugs (AEDs) that can be initiated rapidly are desirable in a variety of clinical situations. Levetiracetam (LEV) is a newer AED, with a recently approved parenteral formulation, that can be initiated at doses effective in controlling seizures. We investigated whether oral loading of levetiracetam is well tolerated and facilitates stabilization and discharge of patients in epilepsy monitoring units (EMU). METHODS: Adult patients in the EMU at two centers were identified who received 1,500 mg of LEV in a single dose. This was an observational study of these patients where LEV was thought to be an appropriate component of the therapeutic regimen. Patients were either LEV naive or had been off all LEV for at least 3 days. LEV maintenance was begun 12 hours later at doses of 500 to 1,000 mg twice a day. RESULTS: A total of 37 adult patients (20 female) were identified. There were no spontaneous complaints of side effects. Upon questioning, 33 patients (89%) denied side effects. The remaining 4 patients (11%) reported transient irritability, imbalance, tiredness, or lightheadedness. Eleven patients (mean weight = 85.0 Kg) had mean LEV serum concentration of 31.5 microg/mL after 1 hour, 23 (mean weight 85.7 Kg) had mean concentration of 30.77 microg/mL after 2 hours, five (mean weight 84.3 Kg) had mean concentration of 12.1 microg/mL after 12 hours, and two (mean weight 94 Kg) had mean concentration of 7.4 microg/mL after 14 hours. No seizures occurred within 24 hours of loading. All patients were able to be discharged 3 to 30 hours after loading. CONCLUSIONS: In the population surveyed, oral loading with levetiracetam was well-tolerated and rapidly yielded serum concentrations thought to decrease seizure frequency. This regimen facilitated discharge from the epilepsy monitoring units.