Rationale and objectives: Carbamazepine has shown reasonable antimanic properties, but its use has been limited because of enzyme-inducing effects. The keto-derivative oxcarbazepine (OXC) is very similar to carbamazepine, however, the metabolic pathway is different. OXC is not metabolized to the 10, 11-epoxide, which seems to be responsible for several undesirable side-effects of carbamazepine and furthermore OXC has less enzyme-inducing properties.
Methods: In this non-random open label study, patients were treated with OXC for 14 days, crossed over to no OXC for 7 days, and then crossed back over to OXC for the remaining 14 days. OXC was titrated to a final dose in a range of 900-2100 mg due to individual response. Treatment success was defined as a reduction of the original Young Mania Rating Scale (YMRS) score of more than 50% at the end of study period.
Results: Four of the 12 included patients (33%) met defined response criteria at the end of study period. Fifty percentage of the patients had to be prematurely excluded from the trial. The mean YMRS scores of the on-periods were obviously different from the off-period. Forty-two percentage of the patients experienced side-effects leading to premature discontinuation in two of 12 patients.
Conclusion: Antimanic activity of OXC was demonstrated in this pilot study only for patients with mild or moderate manic symptoms. Further studies are encouraged to clarify OXC's role as mood-stabilizer and assess whether it has a profile similar to that of carbamazepine.