A double blind, randomized, placebo-controlled trial of quetiapine as an add-on therapy to lithium or divalproex for the treatment of bipolar mania

The aim of this study was to evaluate the efficacy and tolerability of quetiapine combined with lithium or divalproex in the treatment of bipolar mania. Patients were randomized to 6 weeks of quetiapine (up to 800 mg/day) and lithium/divalproex (Li/DVP) (target trough serum concentrations of 0.7-1.0 mEq/L and 50-100 microg/mL, respectively) or placebo and lithium/divalproex. Quetiapine+lithium/divalproex treatment (n=104) showed a 2.0-point greater improvement on the primary outcome (change from baseline in Young Mania Rating Scale total score at day 21) compared with placebo+lithium/divalproex (n=96), and a 2.8-point greater difference by day 42, but the differences between groups were not statistically significant. Other efficacy measures, however, did show a statistically significant advantage in favor of quetiapine+lithium/divalproex over lithium/divalproex monotherapy at day 42. Improvement of mean Young Mania Rating Scale scores with quetiapine+lithium/divalproex was numerically but not statistically significantly greater than lithium/divalproex monotherapy in the treatment of bipolar mania. Potential reasons for the failure of quetiapine+lithium/divalproex to differentiate from placebo+lithium/divalproex treatment on the primary outcome measure and the implications of this for the treatment of mania and future studies are discussed. Overall, the combination of quetiapine with lithium or divalproex was well tolerated.