Starting Dose for Rexulti (Brexpiprazole) for Add-On Depression
The recommended starting dose of brexpiprazole for augmentation of major depressive disorder is 0.5 mg or 1 mg orally once daily, with titration to the target dose of 2 mg once daily based on clinical response and tolerability. 1
Dosing Algorithm
Initial Dosing
- Start: 0.5 mg or 1 mg once daily (either starting dose is acceptable per FDA labeling)
- Administration: Once daily, with or without food 1
Titration Schedule
- Week 1: Titrate to 1 mg once daily if not already started at this dose
- Subsequent weeks: Increase to target dose of 2 mg once daily based on patient's clinical response and tolerability
- Dose adjustments: Make weekly increments as needed 1
Target and Maximum Doses
- Target dose: 2 mg once daily (this is the recommended therapeutic dose) 1
- Maximum dose: 3 mg once daily 1
Clinical Trial Evidence
The pivotal Phase III trials supporting FDA approval used the 2-3 mg/day dosing range in patients with MDD who had inadequate response to antidepressant treatment alone 2, 3. When pooling data from these trials, 23.2% of patients receiving brexpiprazole 1-3 mg were responders versus 14.5% for placebo, yielding a number needed to treat (NNT) of 12 2.
The 2 mg dose demonstrated optimal efficacy in clinical trials - both minimal responders (>0% to <25% improvement on antidepressants) and partial responders (≥25% to <50% improvement) showed statistically significant benefits with adjunctive brexpiprazole 2-3 mg/day compared to placebo 4.
Special Population Adjustments
Hepatic Impairment
- Maximum dose: 2 mg once daily in patients with moderate to severe hepatic impairment (Child-Pugh score ≥7) 1
Renal Impairment
- Maximum dose: 2 mg once daily in patients with creatinine clearance <60 mL/minute 1
CYP2D6 Poor Metabolizers
- Dosage modifications required (see drug interactions section of prescribing information) 1
Tolerability Profile
In MDD trials, discontinuation due to adverse events occurred in only 3% of brexpiprazole-treated patients versus 1% of placebo patients (NNH = 53) 2. The most common adverse event was akathisia (8.6% in MDD trials), with a modest NNH of 15 2. This activation-like side effect profile is important to monitor during titration, though brexpiprazole has lower intrinsic D2 activity than aripiprazole, suggesting lower potential for akathisia 3.
Critical Monitoring Points
- Weeks 1-2: Close monitoring for suicidal thoughts and behaviors is mandatory per FDA black box warning, as antidepressants increase this risk in young adults 1
- Ongoing: Monitor for akathisia, weight gain (modest in short-term trials), and metabolic parameters 2
- Reassessment: Periodically evaluate continued need for treatment and appropriate dosage 1
Common Pitfall to Avoid
Do not start at the target dose of 2 mg - the FDA labeling specifically recommends starting at 0.5 mg or 1 mg and titrating up. Rapid escalation may increase the risk of akathisia and other activation symptoms, potentially leading to premature discontinuation before therapeutic benefit is achieved.