A double-blind, randomized, placebo-controlled prophylaxis trial of oxcarbazepine as adjunctive treatment to lithium in the long-term treatment of bipolar I and II disorder

We evaluated the prophylactic efficacy and the long-term tolerability of oxcarbazepine administration in the treatment of bipolar I and II disorder as an adjunctive therapy to lithium. We conducted a 52-wk, double-blind, randomized, placebo-controlled, parallel-group, multicentre, clinical trial. Bipolar I and II DSM-IV outpatients, having had two or more episodes in the last year, but currently being in remission, were randomly assigned on a 1:1 ratio to oxcarbazepine (n=26) or placebo (n=29) as adjuncts to ongoing treatment with lithium. The primary efficacy variable was the length of the remission period assessed by means of the Young Mania Rating Scale (YMRS) and Montgomery-Asberg Depression Rating Scale (MADRS). Other assessments were the Clinical Global Impression (CGI-BP-M), functional activity (GAF), anxiety (HAMA) and impulsiveness (BIS-11). The average time until first recurrence of any type was 19.2+/-13.9 wk and 18.6+/-17.0 wk for oxcarbazepine and placebo respectively (p=0.315). Ten (38.46%) patients had a recurrence of any kind in the oxcarbazepine group vs. 17 (58.62%) in the placebo group (p=0.1354). There was a trend for depressive episodes being less likely in the oxcarbazepine group compared to the placebo group (11.54% and 31.03% respectively, p=0.085), and for better functionality with the GAF (p=0.074). Impulsivity was significantly better prevented by oxcarbazepine (p=0.0443). Overall, oxcarbazepine was well tolerated. This pilot, randomized clinical trial, suggests that oxcarbazepine might have some prophylactic efficacy with regards to impulsivity and perhaps mood episodes in patients taking lithium, although further, adequately powered controlled trials are needed to confirm these findings.