Bipolar I and II disorder residual symptoms: oxcarbazepine and carbamazepine as add-on treatment to lithium in a double-blind, randomized trial. A double-blind, randomized, placebo-controlled trial of oxcarbazepine in the treatment of bipolar disorder in children and adolescents. Comparative efficacy and safety of oxcarbazepine versus divalproex sodium in the treatment of acute mania: a pilot study.
Bipolar affective disorders often require adjunctive therapy to treat persistent symptoms. In order to evaluate bipolar symptoms inadequately responsive to lithium, we have compared the effects of two structurally related compounds carbamazepine (CBZ) and oxcarbazepine (OXC). We evaluated the efficacy and safety of CBZ and OXC administration in residual symptoms as an adjunctive therapy in Bipolar I (BP I) and Bipolar II (BP II) patients while on lithium maintenance treatment. We selected from 153 bipolar patients in treatment those fulfilling Research Diagnostic Criteria for mania or hypomania, according to the SADS-L and conducted in 52 bipolar patients (27 BP I, 25 BP II) a double-blind, randomized, parallel-group, single centre, clinical trial. Bipolar I and II outpatients, were randomly assigned on a 1:1 ratio to OXC (n=26) or CBZ (n=26) for an 8-week period as add-on treatment to the existing lithium regimen. Outcome measures included the Young Mania Rating Scale (YMRS), Hamilton Depression Rating Scale 21 items (HDRS-21) and Montgomery-Asberg Depression Rating Scale (MADRS), Clinical Global Impression severity (CGI-S) and improvement illness (CGI-I). These scales were administered at baseline and at the end of weeks 2, 4 and 8. All the fifty-two patients completed the trial. Overall, females were 35 (65%) and mean (S.D.) age was 39.4 (11.9) years; final doses at the end of week 8 in OXC group was 637.7 (210) mg/day and in the CBZ group 673.5 (179) mg/day; lithium plasma levels were 0.73 (0.25) meq/l and 0.71 (0.28) meq/l, respectively. Both OXC and CBZ were effective in reducing bipolar scores from baseline to endpoint (p<0.01). OXC was more effective than CBZ at weeks 4 and 8 on all 5 outcome measures. OXC resulted in greater significant mean reductions in YMRS, HDRS-21, MADRS, CGI-S and CGI-I scores from baseline to week 4 (p<0.05) and from baseline to week 8 (p<0.001), except YMRS (p<0.01). OXC appeared to be significantly more effective and with better tolerability than CBZ as add-on strategy treatment in BP I and BP II patients. This pilot, randomized clinical trial, suggests the potential usefulness of OXC as adjunctive therapy to lithium both in acute and long-term treatment of bipolar disorder. However, further adequately placebo-controlled trials are needed to expand these findings. This multicenter trial examined the efficacy and safety of oxcarbazepine in the treatment of bipolar disorder in children and adolescents.
                A total of 116 outpatients 7 to 18 years of age with bipolar I disorder, manic or mixed, were recruited at 20 centers in the United States and randomly assigned to receive 7 weeks of double-blinded, flexibly dosed treatment with oxcarbazepine (maximum dose 900-2400 mg/day) or placebo. The primary efficacy measure was the mean change from baseline to endpoint in the Young Mania Rating Scale (YMRS), using the last-observation-carried-forward method.
                Oxcarbazepine (mean dose=1515 mg/day) did not significantly improve YMRS scores at endpoint compared with placebo [adjusted mean change: oxcarbazepine, -10.90 (N=55); placebo, -9.79 (N=55)]. Dizziness, nausea, somnolence, diplopia, fatigue, and rash were each reported in at least 5% of the patients in the oxcarbazepine group with an incidence at least twice that of the placebo group. The majority of adverse events were mild to moderate and occurred during the titration period. Eleven patients (19%) in the oxcarbazepine group discontinued the study because of adverse events, compared with two (4%) in the placebo group.
                Oxcarbazepine is not significantly superior to placebo in the treatment of bipolar disorder in youths. While the overall adverse event profile was similar to that reported for patients with epilepsy, the incidence of psychiatric adverse events for both the oxcarbazepine and placebo groups was higher than that reported for the epilepsy population. This study compared the efficacy and safety of oxcarbazepine and divalproex sodium in acute mania patients.
                In this 12 week, randomized, double-blind pilot study, 60 patients diagnosed with acute mania (DSM-IV) and a baseline Young Mania Rating Scale (YMRS) score of 20 or more received flexibly dosed oxcarbazepine (1,000-2,400 mg/day) or divalproex (750-2,000 mg/day). The mean decrease in the YMRS score from baseline was used as the main outcome measure of response to treatment. A priori protocol-defined threshold scores were <or=12 for remission and >or=15 for relapse. Number of patients showing adequate response and the time taken to achieve improvement was compared. Adverse events were systematically recorded throughout the study.
                Over 12 weeks, mean improvement in YMRS scores was comparable for both the groups including the mean total scores as well as percentage fall from baseline. There were no significant differences between treatments in the rates of symptomatic mania remission (90% in divalproex and 80% in oxcarbazepine group) and subsequent relapse. Median time taken to symptomatic remission was 56 days in divalproex group while it was 70 days in the oxcarbazepine group (p=0.123). A significantly greater number of patients in divalproex group experienced one or more adverse drug events as compared to patients in the oxcarbazepine group (66.7% versus 30%, p<0.01).
                Oxcarbazepine demonstrated comparable efficacy to divalproex sodium in the management of acute mania. Also the overall adverse event profile was found to be superior for oxcarbazepine.
Currently, there are insufficient trials of adequate methodological quality on oxcarbazepine in the acute treatment of bipolar disorder to inform us on its efficacy and acceptability. Studies predominantly examine the treatment of mania: there are data from subgroup analysis on mixed affective, hypomania and rapid-cycling states.
From the few studies included in this review, oxcarbazepine did not differ in efficacy compared to placebo in children and adolescents. It did not differ from other active agents in adults. It may have a poorer tolerability profile compared to placebo. No data were found on outcomes relevant to patients and clinicians, such as length of hospital admission.  
There is a need for adequately powered randomised controlled trials of good methodological quality to inform us of the therapeutic potential of oxcarbazepine across the spectrum of acute episodes in bipolar disorder.