What is the recommended starting dose and titration schedule of Rexulti (brexpiprazole) for adults, including elderly patients or those with hepatic impairment?

Rexulti Starting Dose

For major depressive disorder (MDD), start Rexulti at 0.5 mg or 1 mg once daily; for schizophrenia in adults, start at 1 mg once daily; for agitation in Alzheimer's dementia, start at 0.5 mg once daily. 1

Dosing by Indication

Major Depressive Disorder (Adjunctive Treatment - Adults)

• Starting dose: 0.5 mg or 1 mg orally once daily
• Titration: Increase to 1 mg daily, then to target dose of 2 mg daily based on response and tolerability
• Titration interval: Weekly dose increases
• Maximum dose: 3 mg daily 1

Schizophrenia (Adults)

• Starting dose: 1 mg orally once daily (Days 1-4)
• Titration: Increase to 2 mg daily on Days 5-7, then may increase to 4 mg on Day 8
• Target dose: 2-4 mg once daily
• Maximum dose: 4 mg daily 1

Schizophrenia (Pediatric Patients 13-17 Years)

• Starting dose: 0.5 mg orally once daily (Days 1-4)
• Titration: Increase to 1 mg daily on Days 5-7, then to 2 mg on Day 8
• Further titration: Weekly increases in 1 mg increments as needed
• Target dose: 2-4 mg once daily
• Maximum dose: 4 mg daily 1

Agitation Associated with Alzheimer's Dementia

• Starting dose: 0.5 mg orally once daily (Days 1-7)
• Titration: Increase to 1 mg daily on Days 8-14, then to 2 mg daily on Day 15
• Target dose: 2 mg once daily
• Maximum dose: 3 mg daily (after at least 14 days at 2 mg, based on response) 1

Special Populations

Hepatic Impairment

For patients with moderate to severe hepatic impairment (Child-Pugh score ≥7):

• MDD or Alzheimer's agitation: Maximum 2 mg daily
• Schizophrenia: Maximum 3 mg daily 1

Renal Impairment

For patients with creatinine clearance <60 mL/minute:

• MDD or Alzheimer's agitation: Maximum 2 mg daily
• Schizophrenia: Maximum 3 mg daily 1

Elderly Patients

While the FDA label does not specify age-based dose reductions for Rexulti itself, elderly patients with dementia-related psychosis have increased mortality risk with antipsychotics. For agitation in Alzheimer's dementia specifically, follow the standard dosing protocol starting at 0.5 mg daily 1.

Drug Interactions Requiring Dose Adjustment

CYP2D6 Poor Metabolizers: Administer half the usual dose 1

Strong CYP3A4 Inhibitors (e.g., itraconazole, clarithromycin): Administer half the usual dose 1

Strong CYP2D6 Inhibitors (e.g., paroxetine, fluoxetine): Administer half the usual dose 1

Concomitant Strong CYP3A4 AND CYP2D6 Inhibitors: Administer one-quarter of the usual dose 1

Strong CYP3A4 Inducers (e.g., rifampin): Double the usual dose over 1-2 weeks; when inducer is discontinued, reduce back to original dose over 1-2 weeks 1

Administration Details

• Timing: Once daily, with or without food
• Formulation: Oral tablets
• Not for PRN use: Particularly important for agitation in Alzheimer's dementia—this is a scheduled daily medication, not as-needed 1

Clinical Considerations

The lower starting doses for MDD (0.5-1 mg) and Alzheimer's agitation (0.5 mg) compared to schizophrenia (1 mg) reflect the different patient populations and risk-benefit profiles. The gradual titration schedule for Alzheimer's agitation (weekly increases) is particularly conservative, appropriate for this vulnerable elderly population with increased mortality risk from antipsychotics 1.

Research data supports that the 2 mg dose for MDD provides the best risk-benefit balance, with doses >2 mg showing higher rates of akathisia and somnolence without proportional efficacy gains 2. For schizophrenia, the 2-4 mg range demonstrates robust efficacy with acceptable tolerability 3, 4.