Lorazepam: a controlled trial in patients with intractable partial complex seizures

Lorazepam was studied in a double-blind, placebo-controlled, crossover trial in eight patients with frequent partial complex seizures refractory to therapy with a combination of standard anticonvulsant drugs. Concomitant antiepileptic drugs were maintained at therapeutic serum levels throughout the study, and concentrations of lorazepam were monitored. Following an 8-week baseline observation, patients were randomly assigned to placebo or lorazepam (1 mg BID). The dose was increased biweekly until seizures stopped or unacceptable side effects occurred. Eight weeks later, patients were crossed over, and the same escalating dose paradigm was followed. When seizure frequency during the last 2 weeks of each treatment was compared, seven of eight patients had fewer seizures on lorazepam, and the eighth had decreased seizure duration (a significant difference: p less than 0.01, two-tailed sign test). Blood level data suggest a narrow therapeutic window, with seizure improvement occurring at concentrations of 20-30 ng/ml and side effects at greater than 33 ng/ml. Lorazepam appears to be a useful adjunct in refractory partial complex seizure therapy. It should not be stopped abruptly, as an increase in seizure frequency may result.