Abstracts

Levetiracetam (LEV) is a new antiepileptic drug licensed for add-on treatment of patients with partial seizures with or without secondary generalization. In several placebo-controlled clinical studies its efficacy as well as tolerability has been demonstrated. Although the mechanism of action of LEV has not been fully elucidated , the drug does not appear to act at any recognized site of antiepileptic drug activity implying a potentially unique mechanism of action. So far, only few patients with increase of seizure frequency have been reported under LEV medication which can occur with every antiepileptic drug treatment. We report two patients with intractable epilepsy with partial seizures who developed a nonconvulsive status epilepticus on treatment with LEV. Both patients never had a status epilepticus in their medical history. Patient 1: 71 year old male patient with symptomatic epilepsy with complex partial seizures after radiotherapy of a frontal astrocytoma 1985. Seizure frequency 1-3 seizures per month with carbamazepine (CBZ) monotherapy. Add-on LEV in a dosage of 2000 mg/day since end of 2001. In april 2003 emergency admission in nonconvulsive status epilepticus by means of clinical status and EEG pattern. After intravenous administration of clonazepam the manifestations ceased. CBZ monotherapy was started.
Patient 2: 30 year old male patient with epilepsy with primary complex partial seizures due to mesial temporal lobe sclerosis. Seizure frequency on treatment with valproic acid (VPA) and CBZ was 1 - 2 seizures per month. Following presurgical monitoring with only one seizure after drug withdrawal LEV monotherapy was started with dosage up to 2000 mg/day. After a 4-week seizure free interval the patient was admitted in nonconvulsive status epilepticus with complex partial seizures. Diagnosis was made on clinical presentation and EEG changes. Status ceased under intravenous treatment with clonazepam. LEV was tapered off and lamotrigin started. Te patient was again admitted in nonconvulsive status epilepticus while still on 500 mg LEV per day. Status ceased again on intravenous clonazepam, LEV was discontinued. In both patients first-ever nonconvulsive focal status epilepticus occurred on treatment with LEV monotherapy in a dosage of 2000 mg/day. Patient 2 even had status recurrence under 500 mg LEV. We postulate a correlation between occurrence of nonconvulsive status and treatment with LEV in these two patients.To our knowledge, apart from singular mentally retarded patients with status epilepticus under high dosages of LEV this has not been described before. Seizure aggravation as well as a possible paradoxical effect have to be considered as underlying mechanism.