OBJECTIVE:

To evaluate the efficacy and tolerability of topiramate monotherapy in adults with acute manic or mixed episodes of bipolar I disorder.

METHODS:

In four trials, adults hospitalized with acute mania, a diagnosis of bipolar I disorder, history of > or =1 previous manic or mixed episodes, and > or =20 Young Mania Rating Scale (YMRS) score were randomized to double-blind treatment with topiramate (target doses: 200, 400, or 600 mg/day) or placebo; two trials included an active comparator (lithium, 1500 mg/day). The core study duration in all trials was 3 weeks; three trials also had 9-week double-blind extensions. The primary efficacy variable was mean change from baseline in YMRS in the core 3-week study.

RESULTS:

Changes in YMRS score during 3 weeks were not significantly different for topiramate versus placebo (mean YMRS reductions, -5.1 to -8.4). Mean YMRS reductions in lithium-treated groups were significantly greater (p < or = 0.001 versus placebo and topiramate). A similar pattern was observed after 12 weeks of double-blind treatment in studies with double-blind extensions. Paresthesia, appetite decrease, dry mouth, and weight loss were more frequently associated with topiramate than with placebo.

CONCLUSIONS:

These studies do not support the efficacy of topiramate as monotherapy in acute mania or mixed episodes in adults with bipolar I disorder. Topiramate was not associated with mood destabilization measured as mania exacerbation or treatment-emergent depression. Lithium was confirmed as an effective therapy in this population.