Objectives: The aim of this preliminary open-label trial was to evaluate the efficacy and safety of oxcarbazepine (OXC) as adjunctive therapy in 18 patients with bipolar disorder who did not respond satisfactorily to lithium.
Methods: Eighteen patients with bipolar I (n=16) and bipolar II (n=2) disorder were treated openly with OXC for a 8-week period as add-on treatment to the existing lithium regimen. After the 8-week trial, all patients continued the treatment with OXC, and were followed-up prospectively. Outcome measures included the Clinical Global Impression-Bipolar Version Scale, the Bech-Rafaelsen Mania-Melancholia Scale and the Brief Psychiatric Rating Scale. These scales were administered at baseline and at the end of weeks 2, 4 and 8. Patients were subsequently assessed every 4 months for a period of time ranging from 4 to 12 months with the Longitudinal Interval Follow-up Evaluation.
Results: The mean dose of OXC at the end of week 8 was 919.4 mg/day (SD+/-335.7). Eleven of the 18 patients were considered responders. The remaining seven patients were rated as nonresponders. Of the eleven responders to the 8-week trial, seven patients remained mood-stabilized for the entire period of follow-up.
Conclusions: OXC appeared to be significantly effective as add-on strategy in 60% of patients after 8 weeks of treatment. A substantial proportion (66.3%) of the 8-week trial responders maintained a satisfactory mood stabilization during the follow-up. Despite several limitations, our study suggests the potential usefulness of OXC as adjunctive therapy to lithium both in acute and long-term treatment of bipolar disorder.