A three-month post marketing surveillance investigated the efficacy and tolerability of the sustained release sodium valproate formulation (Orfiril ® retard) in 366 patients with primary generalised or focal seizures. 87 patients were newly diagnosed drug-naive patients, 116 patients had received prior antiepileptic treatment except valproate and 163 patients were receiving conventional valproate preparations. The seizure frequency was reduced and the number of seizure-free patients increased in all subgroups during the observation period. The incidence of adverse events with 16% was lower than under previous therapy. The results of the study show that sustained release valproate can be initially introduced successfully in newly diagnosed patients. Patients who are not seizure-free under other antiepileptic medication benefit from valproate treatment. Patients under conventional valproate therapy may be switched to the same daily dose of sustained release valproate which is administered in a more convenient b.i.d. or once daily dose regimen. This improves the clinical efficacy and tolerability and results in better patient acceptance and compliance.

        Key words: epilepsy, pharmacotherapy, sodium valproate