Predictors of response to carbamazepine extended-release capsules treatment in bipolar disorder.
BACKGROUND
Predictors of response to psychoactive drugs are valuable in providing practical guidance and in optimizing a treatment regimen. Here we used linear regression analysis to identify treatment-specific predictors of response to therapy with beaded extended-release carbamazepine capsules (CBZ-ERC) (Shire, Wayne, PA, USA) in 600 outpatients with bipolar disorder.


METHODS
Data were obtained from medical charts of subjects who received CBZ-ERC in a private practice setting. Illness severity and improvement were assessed using the Clinical Global Impression-Severity (CGI-S) and Clinical Global Impression-Improvement (CGI-I) scales.


RESULTS
We found that increasing baseline CGI-S scores correlated with lower CGI-I scores (R2=0.01, p=0.009); that is, the higher the baseline CGI-S score, the greater the expected degree of improvement. There was also a correlation between increasing CBZ-ERC dose and improvement in CGI-I scores (R2=0.02; p=0.0004). Moreover, we found that increasing carbamazepine (CBZ) blood concentration correlated with decreases in CGI-I scores (R2=0.12; p=0.025), and that there was a correlation between higher total daily CBZ-ERC dose in mg/kg of body weight and decreases in CGI-I scores (R2=0.01; p=0.038).


CONCLUSIONS
These findings suggest that bipolar patients with more severe baseline symptoms, on higher CBZ-ERC doses, and with higher CBZ blood levels were more likely to respond to CBZ-ERC treatment.
Ginsberg
Lawrence D
LD
Red Oak Psychiatry Associates, Houston, TX 77090, USA. larrydg@earthlink.net
D000328:Adult; D018692:Antimanic Agents / Q000627:therapeutic use*; D001714:Bipolar Disorder / Q000175:diagnosis / Q000188:drug therapy*; D002214:Capsules; D002220:Carbamazepine / Q000627:therapeutic use*; D003692:Delayed-Action Preparations / Q000627:therapeutic use; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005260:Female; D006801:Humans; D008297:Male; D011379:Prognosis; D012044:Regression Analysis; D012189:Retrospective Studies
D018692:Antimanic Agents; D002214:Capsules; D003692:Delayed-Action Preparations; D002220:Carbamazepine