Reassessing Carbamazepine in the Treatment of Bipolar Disorder Clinical Implications of New Data

Abstract

This monograph summarizes the proceedings of a roundtable meeting convened to discuss the role of carbamazepine in the treatment of bipolar disorder, in light of new data and the recent indication of carbamazepine extended-release capsules (CBZ ERC) for use in the treatment of acute manic and mixed episodes. Two lectures were presented, followed by a panel discussion among all 6 participants. A summary of the two pivotal trials of CBZ ERC and their pooled data along with other relevant data is presented first. Next, historical trends of carbamazepine and the agent's use in acute mania, bipolar depression, and maintenance are reviewed, emphasizing clinical implications of efficacy, safety, tolerability, and drug interactions. Finally, the panel discussion provides recommendations for the use of carbamazepine in different phases of the illness, taking into account adverse effects and drug-drug interactions.

Panel discussants agree that current data confirm the utility of CBZ ERC as an effective treatment for acute manic and mixed episodes in bipolar disorder. Carbamazepine may also prove to be an option for maintenance treatment. Tolerability of the drug is related to dose and titration, and overall safety limitations regarding carbamazepine usage are comparable to other medications. For some patients, the main challenges to use of carbamazepine may be common drug-drug interactions and increased side effects related to aggressive introduction during treatment of acute manic and mixed episodes. Thus, carbamazepine may be a lower priority option for patients who are taking multiple medications, such as elderly individuals with medical comorbidity, due to the potential for drug interactions. Important benefits of carbamazepine include the low propensity toward weight gain and evidence of good tolerability with long-term treatment. (At present there are no available data from long-term, placebo-controlled studies evaluating the effects of carbamazepine or CBZ ERC on weight.) Thus, carbamazepine may be a good option for patients who are concerned about weight gain or who are intolerant of or respond poorly to other medications. Further efforts are needed to update physicians on the use of carbamazepine relative to other medications in the treatment of bipolar disorder.