Rexulti (Brexpiprazole) for Bipolar I Disorder
Rexulti is NOT FDA-approved for bipolar I disorder and failed to demonstrate efficacy in clinical trials for acute mania. While it is FDA-approved for major depressive disorder (as adjunctive therapy) and schizophrenia, you should use established first-line agents for bipolar I disorder instead 1.
Evidence Against Use in Bipolar I Disorder
The most definitive evidence comes from two failed Phase 3 trials specifically designed to test brexpiprazole for acute mania in bipolar I disorder. Both randomized, double-blind, placebo-controlled studies (n=164-170 per arm) showed no statistically significant difference between brexpiprazole 2-4 mg/day and placebo on the primary endpoint (YMRS total score change at day 21) 2. Study 080 showed a difference of only 0.14 points (p=0.88), and Study 081 showed -1.62 points (p=0.10)—neither clinically nor statistically meaningful 2.
Interestingly, post-hoc analysis suggested brexpiprazole might work better in patients with impaired insight (predominantly European patients) versus those with excellent insight (predominantly US patients), but this doesn't change the fact that the primary studies failed 2.
What IS FDA-Approved for Bipolar I Disorder
The FDA label for Rexulti explicitly lists only three approved indications, and bipolar disorder is not among them 1:
- Adjunctive treatment for major depressive disorder (with antidepressants)
- Schizophrenia (adults and children ≥13 years)
- Agitation associated with dementia due to Alzheimer's disease
Established Treatment Options for Bipolar I Disorder
For acute mania in bipolar I disorder, use FDA-approved agents with proven efficacy 3:
First-Line Options:
- Lithium (approved down to age 12 for acute mania and maintenance)
- Valproate
- Atypical antipsychotics with proven efficacy:
- Aripiprazole (approved for acute mania in adults)
- Olanzapine (approved for acute mania and maintenance)
- Risperidone (approved for acute mania)
- Quetiapine (approved for acute mania)
- Ziprasidone (approved for acute mania)
For Maintenance Therapy:
- Lithium
- Lamotrigine
- Olanzapine
For Bipolar Depression:
- Olanzapine + fluoxetine combination
Limited Pilot Data for Bipolar Depression
One small open-label pilot study (n=21) examined brexpiprazole for bipolar depression and found reduced depressive symptoms on MADRS and improved quality of life over 8 weeks 4. However, this was an uncontrolled, open-label study without a placebo comparison—insufficient evidence to recommend use. The lack of controlled data and the failed mania trials make this preliminary finding unreliable for clinical decision-making.
Clinical Bottom Line
Do not use Rexulti for bipolar I disorder. Start with lithium, valproate, or an FDA-approved atypical antipsychotic (aripiprazole, olanzapine, risperidone, quetiapine, or ziprasidone) based on:
- Phase of illness (acute mania vs. depression vs. maintenance)
- Presence of psychotic features or mixed episodes
- Side effect profile tolerance
- Patient's prior medication response
- Family history of treatment response
The evidence is clear: brexpiprazole failed in controlled trials for the condition you're asking about, while multiple other agents have proven efficacy and FDA approval for bipolar I disorder 3, 2.