Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice.

The most common adverse reactions in adult patients in clinical trials (≥5%) were weight increased, akathisia, headache, somnolence, and insomnia.

The most common adverse reactions in pediatric patients in clinical trials (≥5%) were weight increased, somnolence, headache, akathisia, and nasopharyngitis.

Brexpiprazole has been evaluated for safety in 12,550 adult patients who participated in multiple-dose clinical trials for major depressive disorder, schizophrenia, agitation associated with dementia due to Alzheimer's disease, attention deficit hyperactivity disorder (ADHD), post-traumatic stress disorder (PTSD), bipolar mania, and borderline personality disorder (BPD). Among them, 3,870 patients were treated with brexpiprazole for at least 180 days, and 1,910 patients were treated for at least one year of exposure.

Additionally, brexpiprazole has been evaluated for safety in 119 pediatric patients who participated in short-term trials, and 314 patients in long-term multiple-dose clinical trials for pediatric schizophrenia and autism spectrum disorders (ASD).

The following adverse reaction has been identified during post-approval use of REXULTI. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.