Brexpiprazole (Rexulti)

Brexpiprazole (Rexulti) is an atypical antipsychotic used to treat schizophrenia and major depressive disorder (MDD) as an adjunctive treatment in adults. It is also sometimes prescribed for bipolar disorder and agitation in dementia.

Mechanism of Action:
  • Dopamine Modulation:
    Brexpiprazole is a partial agonist at dopamine D2 and D3 receptors. This means it can both activate and block dopamine receptors, depending on the surrounding levels of dopamine, which helps to normalize dopamine activity in areas of the brain associated with mood, cognition, and psychotic symptoms.
    • Its higher affinity for D3 receptors compared to D2 receptors may help improve cognitive symptoms in disorders like schizophrenia.
  • Serotonin Modulation:
    Brexpiprazole also has activity at serotonin receptors, including 5-HT1A (where it acts as a partial agonist) and 5-HT2A (where it acts as an antagonist). This serotonin modulation plays a role in mood regulation and antidepressant effects.
  • Action in Depression:
    By balancing both dopamine and serotonin, brexpiprazole is effective as an adjunctive treatment for depression, especially for people who have not responded well to antidepressants alone.
  • Benefits:
  • Schizophrenia:
    Brexpiprazole is effective in treating the positive symptoms (such as hallucinations and delusions) and negative symptoms (such as apathy and lack of motivation) associated with schizophrenia.
    • Clinical studies have shown that it significantly reduces symptoms, leading to improved social functioning and cognitive performance.
  • Major Depressive Disorder (MDD):
    As an adjunct to antidepressants, brexpiprazole has shown efficacy in treating resistant depression. When combined with antidepressants, it helps boost the antidepressant response, making it a useful option for individuals who do not respond to monotherapy.
  • Bipolar Disorder:
    Although not FDA-approved specifically for bipolar disorder, brexpiprazole is sometimes used off-label for the treatment of mania or bipolar depression in combination with mood stabilizers or antidepressants.

  • Dosage:
  • Schizophrenia:
    • Starting dose: 1 mg once daily for the first 4 days.
    • Maintenance dose: Typically 2–4 mg/day, based on individual response and tolerability.
    • Maximum dose: 4 mg/day.
  • Major Depressive Disorder (Adjunctive Treatment):
    • Starting dose: 0.5 mg or 1 mg once daily.
    • Maintenance dose: 1–3 mg/day depending on patient response.
    • Maximum dose: 3 mg/day.
  • Bipolar Disorder (off-label use):
    • For manic episodes, the typical dosage follows the schizophrenia dosing, starting at 1 mg/day and increasing to a maximum of 4 mg/day.
  • Brexpiprazole can be taken once daily, with or without food.

    Side Effects:
  • Common Side Effects:
    • Weight gain: Occurs in 5-10% of patients.
    • Akathisia (restlessness): Reported in about 10-15% of patients, leading to discomfort or difficulty sitting still.
    • Drowsiness/sedation: Experienced by 10-15% of patients, but less pronounced than with some other atypical antipsychotics.
    • Headache: Occurs in about 5-10% of patients.
    • Nausea: Reported in 5-10% of patients.
    • Insomnia: Reported in 5% of patients.
  • Serious Side Effects:
    • Tardive Dyskinesia (involuntary movements): A rare but serious side effect. Risk increases with long-term use.
    • Neuroleptic Malignant Syndrome (NMS): A potentially life-threatening condition (rare).
    • Increased risk of suicidal thoughts: Particularly in children, adolescents, and young adults. Close monitoring is recommended.
  • Metabolic Effects:
    • Weight gain and changes in cholesterol or blood sugar levels are generally milder compared to some other atypical antipsychotics.

  • Prevalence of Side Effects:
  • Akathisia: Occurs in 10-15% of patients, typically more noticeable in higher doses. (drugs.com)
  • Drowsiness: Reported in 10-15% of patients, but this effect is less pronounced than with many other atypical antipsychotics. (drugs.com)
  • Nausea: Occurs in 5-10% of patients. (drugs.com)

  • Summary:Brexpiprazole (Rexulti) is a versatile atypical antipsychotic used for schizophrenia and major depressive disorder, and sometimes for bipolar disorder. It is particularly helpful as an adjunct for depression, with a low risk of metabolic side effects compared to other atypicals. The most common side effects are akathisia, drowsiness, and nausea, while more severe effects like tardive dyskinesia and NMS are rare. It offers a favorable side-effect profile for those needing long-term antipsychotic treatment.