The mechanism of action of brexpiprazole in the treatment of major depressive disorder or schizophrenia is unknown. However, the efficacy of brexpiprazole may be mediated through a combination of partial agonist activity at serotonin 5-HT_1A and dopamine D₂ receptors, and antagonist activity at serotonin 5-HT_2A receptors.

Brexpiprazole is an atypical antipsychotic indicated for:

• Use as an adjunctive therapy to antidepressants for the treatment of major depressive disorder (MDD)
• Treatment of schizophrenia

Adjunctive Treatment of Major Depressive Disorder: The recommended starting dosage for Brexpiprazole as adjunctive treatment is 0.5 mg or 1 mg once daily, taken orally with or without food. Titrate to 1 mg once daily, then up to the target dosage of 2 mg once daily. Dosage increases should occur at weekly intervals based on the patient's clinical response and tolerability. The maximum recommended daily dosage is 3 mg. Periodically reassess to determine the continued need and appropriate dosage for treatment.

Treatment of Schizophrenia: The recommended starting dosage for Brexpiprazole is 1 mg once daily on Days 1 to 4, taken orally with or without food. The recommended target Brexpiprazole dosage is 2 mg to 4 mg once daily. Titrate to 2 mg once daily on Day 5 through Day 7, then to 4 mg on Day 8 based on the patient’s clinical response and tolerability. The maximum recommended daily dosage is 4 mg.

Brexpiprazole is contraindicated in patients with a known hypersensitivity to brexpiprazole or any of its components. Reactions have included rash, facial swelling, urticaria, and anaphylaxis.

Cerebrovascular Adverse Reactions in Elderly Patients with Dementia-

• Related Psychosis: Increased incidence of cerebrovascular adverse reactions (e.g. stroke, transient ischemic attack)
• Neuroleptic Malignant Syndrome: Manage with immediate discontinuation and close monitoring
• Tardive Dyskinesia: Discontinue if clinically appropriate
• Metabolic Changes: Monitor for hyperglycemia/diabetes mellitus, dyslipidemia and weight gain
• Pathological Gambling and Other Compulsive Behaviors: Consider dose reduction or discontinuation
• Leukopenia, Neutropenia, and Agranulocytosis: Perform complete blood counts (CBC) in patients with pre-existing low white blood cell count (WBC) or history of leukopenia or neutropenia. Consider discontinuing Brexpiprazole if a clinically significant decline in WBC occurs in absence of other causative factors
• Orthostatic Hypotension and Syncope: Monitor heart rate and blood pressure and warn patients with known cardiovascular or cerebrovascular disease, and risk of dehydration or syncope
• Seizures: Use cautiously in patients with a history of seizures or with conditions that lower the seizure threshold

Use in Special Populations

Dosage Adjustments for Hepatic Impairment: For patients with moderate to severe hepatic impairment, the maximum recommended dosage is 2 mg once daily for patients with MDD, and 3 mg once daily for patients with schizophrenia

Dosage Adjustments for Renal Impairment: For patients with moderate, severe or end-stage renal impairment (creatinine clearance ClCr<60 mL/minute), the maximum recommended dosage is 2 mg once daily for patients with MDD and 3 mg once daily for patients with schizophrenia

Pediatric Use: Safety and effectiveness in pediatric patients have not been established. Antidepressants increased the risk of suicidal thoughts and behaviors in pediatric patients

Geriatric Use: In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, and cardiac function, concomitant diseases, and other drug therapy.

Pregnancy & Lactation

There is a pregnancy exposure registry that monitors pregnancy outcomes in women exposed to Brexpiprazole during pregnancy.

Lactation studies have not been conducted to assess the presence of brexpiprazole in human milk, the effects of brexpiprazole on the breastfed infant, or the effects of brexpiprazole on milk production. Brexpiprazole is present in rat milk. The development and health benefits of breastfeeding should be considered along with the mother’s clinical need for Brexpiprazole and any potential adverse effects on the breastfed infant from Brexpiprazole or from the underlying maternal condition.