Rexulti (Brexpiprazole): Approved Indications, Dosing, and Monitoring
Rexulti (brexpiprazole) is FDA-approved for three indications in adults: adjunctive treatment of major depressive disorder (MDD), treatment of schizophrenia (adults and adolescents ≥13 years), and treatment of agitation associated with Alzheimer's dementia. 1
FDA-Approved Indications
Rexulti is indicated for:
- Adjunctive treatment to antidepressants for MDD in adults
- Treatment of schizophrenia in adults and pediatric patients ages 13 years and older
- Treatment of agitation associated with dementia due to Alzheimer's disease (not as PRN/"as needed" therapy) 1
Dosing Regimens
Major Depressive Disorder (Adjunctive Treatment - Adults)
Start at 0.5-1 mg once daily, titrate to target dose of 2 mg daily over weekly intervals based on response and tolerability. 1
- Starting dose: 0.5 mg or 1 mg orally once daily
- Target dose: 2 mg once daily
- Maximum dose: 3 mg once daily
- Titration: Increase at weekly intervals based on clinical response
- Administer with or without food 1
Schizophrenia
Adults
Start at 1 mg daily for Days 1-4, increase to 2 mg on Days 5-7, then may increase to 4 mg on Day 8 based on response. 1
- Starting dose: 1 mg once daily (Days 1-4)
- Initial titration: 2 mg once daily (Days 5-7)
- Target dose: 2-4 mg once daily
- Maximum dose: 4 mg once daily
- May increase to 4 mg on Day 8 based on clinical response and tolerability 1
Pediatric Patients (13-17 years)
Start at 0.5 mg daily for Days 1-4, increase to 1 mg on Days 5-7, then 2 mg on Day 8. 1
- Starting dose: 0.5 mg once daily (Days 1-4)
- Initial titration: 1 mg daily (Days 5-7), then 2 mg on Day 8
- Target dose: 2-4 mg once daily
- Maximum dose: 4 mg once daily
- Weekly dose increases can be made in 1 mg increments 1
Agitation Associated with Alzheimer's Dementia
Start at 0.5 mg daily for one week, increase to 1 mg for the second week, then 2 mg on Day 15 as the target dose. 1
- Starting dose: 0.5 mg once daily (Days 1-7)
- Week 2: 1 mg once daily (Days 8-14)
- Target dose: 2 mg once daily (starting Day 15)
- Maximum dose: 3 mg once daily (after at least 14 days at 2 mg, based on response) 1
Dose Adjustments for Special Populations
Hepatic Impairment
Maximum dose is 2 mg daily for MDD/Alzheimer's agitation and 3 mg daily for schizophrenia in patients with moderate-to-severe hepatic impairment (Child-Pugh score ≥7). 1
Renal Impairment
Maximum dose is 2 mg daily for MDD/Alzheimer's agitation and 3 mg daily for schizophrenia when creatinine clearance <60 mL/minute. 1
CYP2D6 Poor Metabolizers and Drug Interactions
Dose adjustments are required for CYP2D6 poor metabolizers and when using concomitant CYP3A4 or CYP2D6 inhibitors/inducers. 1
- With strong CYP3A4 inhibitors OR strong CYP2D6 inhibitors: Reduce dose to half the usual dose
- With both strong CYP3A4 AND CYP2D6 inhibitors: Reduce dose to one-quarter of usual dose
- With strong CYP3A4 inducers: Double the usual dose over 1-2 weeks; when inducer discontinued, reduce back to original dose over 1-2 weeks 1
Critical Safety Warnings
Black Box Warnings
Two black box warnings apply: 1
- Increased mortality in elderly patients with dementia-related psychosis - Rexulti is NOT approved for dementia-related psychosis without agitation associated with Alzheimer's disease
- Suicidal thoughts and behaviors - Increased risk in pediatric and young adult patients; close monitoring required for clinical worsening
Important: Rexulti is NOT approved for pediatric MDD 1
Monitoring Requirements
Clinical Monitoring
Based on the pharmacologic profile and clinical trial data 2, 3, 4:
- Weight: Monitor regularly; approximately 10% of patients gain ≥7% body weight in short-term trials (NNH=17), with more outliers in long-term studies 2, 4
- Metabolic parameters: Check glucose and lipids periodically (effects are generally small) 2, 3
- Akathisia: Monitor for extrapyramidal symptoms, particularly akathisia (incidence 5.5% in schizophrenia, 8.6% in MDD vs. placebo) 4
- Suicidality: Close monitoring in all antidepressant-treated patients, especially early in treatment 1
- Prolactin: Minimal effects observed; routine monitoring not typically required 2, 3
Laboratory Monitoring
- Baseline: Glucose, lipids, weight
- Periodic: Glucose and lipid monitoring during treatment (frequency based on individual risk factors)
- ECG: No clinically relevant QTc prolongation observed in trials; routine monitoring not required unless specific cardiac risk factors present 2, 3
Common Adverse Effects
The most common adverse events (≥4% and at least twice placebo rate) include: 1, 2, 4
- Weight gain (most common in product labeling)
- Akathisia (NNH=112 for schizophrenia, NNH=15 for MDD)
- Gastrointestinal effects (in MDD trials)
- Headache
- Somnolence
Discontinuation rates due to adverse events are generally low: 3% for MDD (NNH=53) and lower than placebo in schizophrenia trials 4
Clinical Efficacy Summary
Schizophrenia
Brexpiprazole 2-4 mg daily demonstrates significant efficacy with NNT=7 for acute treatment and NNT=4 for relapse prevention. 2, 4
- Pooled responder rates: 46% vs. 31% placebo (NNT=7)
- Relapse prevention: 13.5% vs. 38.5% placebo relapsed (NNT=4) 2, 4
Major Depressive Disorder (Adjunctive)
As adjunctive therapy, brexpiprazole shows modest efficacy with NNT=12. 4
- Response rates: 23.2% vs. 14.5% placebo (NNT=12) 4
Alzheimer's Agitation
Brexpiprazole 2 mg demonstrates optimal therapeutic benefit for agitation in Alzheimer's disease. 5
- Significant improvements in CMAI scores (MD: -5.88) and CGI-S scores (MD: -0.48) at 2 mg dose 5
Key Clinical Pearls
- Titration is mandatory - rapid titration increases risk of adverse effects, particularly akathisia
- Once-daily dosing provides convenience and may improve adherence 6, 3
- Lower activation potential compared to aripiprazole due to less intrinsic D2 activity 2, 6, 3
- Moderate weight gain is the primary metabolic concern; more pronounced with long-term use 2, 4
- Drug interactions are clinically significant - always check for CYP3A4/2D6 inhibitors or inducers 1