Divalproex extended-release versus the original divalproex tablet: results of a randomized, crossover study of well-controlled epileptic patients with primary generalized seizures.

PURPOSE

To compare the safety and efficacy of two formulations of divalproex, extended-release divalproex versus the original divalproex tablet, in adolescent and adult patients with epilepsy.

METHODS

Eligible patients were between the ages of 12 and 65 years with primary generalized epilepsy, which was controlled over the month prior to study enrollment with divalproex or valproic acid 1000 mg to 2000 mg/day. The patients were well-controlled; 39 of 43 (91%) had no seizures in the previous year. Patients were randomized to receive 84 days of either divalproex two times a day (b.i.d.)/three times a day (t.i.d.) or extended-release divalproex qd and then (crossed over to) 84 days of the comparator formulation. During the two treatment periods, patients received the same daily dose equivalent of divalproex as was taken during the month prior to study entry. The clinical status of patients was evaluated at a screening visit and at four subsequent visits conducted every 42 days.

RESULTS

There was no statistically significant difference between the formulation groups for seizure control rate (95% [41/43] for divalproex and 93% [40/43] for extended-release divalproex). Likewise, the formulation groups were similar based on the incidence of treatment-related adverse events. The most frequently reported (< or =11.4% for either formulation) treatment-related adverse events were asthenia, tremor, nausea, and dizziness.

CONCLUSIONS

Extended-release divalproex was similar to divalproex for the treatment of well-controlled, primary generalized epilepsy in terms of overall safety and efficacy parameters.