Carbamazepine Extended-Release Capsules Use in Bipolar Disorder: Efficacy and Safety in Adult Patients

Abstract

Safety, tolerability, and efficacy of carbamazepine (CBZ) have been demonstrated in numerous studies over the last three decades. Until recently, CBZ studies largely involved immediate-release formulations, while long-term studies have been few in number. The recent development of beaded CBZ extended-release capsules (CBZ-ERC) (Shire, Wayne, PA, USA) provides a new formulation with potential advantages in safety, tolerability, and efficacy over earlier formulations. The present study assesses these parameters in patients of various bipolar subtypes (mixed/manic, bipolar I depression, and bipolar II), in a single-site private practice setting. Data were obtained from the charts of 300 patients>or=18 years old who met DSM-IV criteria for bipolar disorder. Clinical response to CBZ-ERC therapy was defined as a score of <or=3 on the Clinical Global Impression-Improvement (CGI-I) scale, while relapse was defined as a change in CGI-I to >or=4 in those subjects who had previously achieved clinical response. Clinical response occurred in 73% of patients, leading to a mean CGI-I score of 2.5 (SD=1.2). Relapse was seen in 33% of responders. Most common adverse events were somnolence, dizziness, and nausea. A high level of treatment response and a low relapse rate were observed in long-term treatment with CBZ-ERC in adults with bipolar disorder. The limited number and nature of the adverse events observed during the course of this study provide evidence of the safety and tolerability of CBZ-ERC. Carbamazepine extended-release capsules appear safe and efficacious for the treatment of bipolar disorder. Controlled studies are warranted to further establish the safety, tolerability, and efficacy of CBZ-ERC for treatment of adult bipolar patients.