A comparison of carbamazepine divitabs with carbamazepine normal formulation in psychiatric and oligophrenic patients. Preliminary pharmacokinetic results.

In an open, randomized, two-centre, cross-over study 20 patients formerly adjusted to a stable oral twice daily 200-600 mg carbamazepine dose, used ordinary tablets and divitabs (a new sustained-release formulation) for periods of three weeks, whereafter the serum level courses of carbamazepine and its metabolite carbamazepine-10,11-epoxide were measured. The mean peak/mean trough carbamazepine-serum concentration ratio was slightly lower after the intake of divitabs in comparison to normal formulation: 1.14 +/- 0.447 versus 1.23 +/- 0.545 (mean +/- SD). The mean trough levels of carbamazepine and its metabolite were 9% and 16% lower in the case of divitabs. In patients with peak/trough carbamazepine-serum level ratios of at least 1.30 after the intake of normal formulation, divitabs had a significant advantage.