The efficacy and tolerability of chewable carbamazepine compared to conventional carbamazepine in patients with epilepsy

Abstract

Carbamazepine (CBZ) is a widely used antiepileptic drug (AED). Recently, a chewable tablet (Tegretol chewtabs) has been formulated. This open substitution study was designed to compare the two formulations with respect to efficacy and tolerability in patients with intractable epilepsy. Thirty patients (24 males, 6 females, mean age 46 years, range 28–83) were studied. Duration of epilepsy was 21–68 years (median 34 years). Four patients were taking CBZ monotherapy, 17, 6 and 3 patients were respectively taking CBZ plus 1, 2 and 3 additional AEDs. Upon entry to study, patients were switched to an equivalent dose of chewtabs and subsequently evaluated at 2, 4, 8 and 12 weeks. Two patients did not complete the study. On entry, the mean 14 day seizure rate was 2.5. On chewtabs mean 14 day rates were 2.4, 2.2, 2.4 and 2.7 after 2, 4, 8 and 12 weeks of treatment respectively. On entry the mean steady state trough serum CBZ concentration was 35 μmol/l compared to 32, 31, 32 and 34 μmol/l after 2, 4, 8 and 12 weeks respectively. Nineteen patients were classified showing good or excellent tolerability, 7 satisfactory and 2 fair. In conclusion, chewtabs were essentially equivalent to the conventional formulation in efficacy and tolerability. After 12 weeks treatment, 19 patients preferred the chewable formulation.