What are the differences between Rexulti (brexpiprazole) and Auvelity (dextromethorphan‑bupropion) in the treatment of dementia?

Neither Rexulti nor Auvelity Should Be Used for Dementia Treatment—With One Critical Exception

Neither Rexulti (brexpiprazole) nor Auvelity (dextromethorphan-bupropion) are approved or recommended for treating dementia itself; however, Rexulti is FDA-approved specifically for agitation associated with Alzheimer's dementia, while Auvelity has no approved indication for any dementia-related condition.

Key Differences

Rexulti (Brexpiprazole)

FDA-Approved Indication for Dementia:

• Approved in 2023 for agitation associated with dementia due to Alzheimer's disease 1
• This is NOT for treating dementia or cognitive decline—only for managing agitation symptoms
• Must be used as maintenance therapy, NOT as-needed (PRN) 1, 2

Mechanism & Dosing:

• Partial dopamine D2 and serotonin 5-HT1A receptor agonist with 5-HT2A antagonism 2
• Start 0.5 mg daily for 7 days, increase to 1 mg on days 8-14, then 2 mg on day 15 (target dose)
• Maximum 3 mg daily 1
• Takes 6-12 weeks to separate from placebo—requires patience 3

Efficacy:

• Showed approximately 5-point greater reduction on Cohen-Mansfield Agitation Inventory versus placebo at 12 weeks 2
• Effect sizes are modest 4
• Works best in patients with severe agitation/aggression 3
• Also reduces caregiver distress 5

Critical Safety Warnings:

• BLACK BOX WARNING: Increased mortality in elderly patients with dementia-related psychosis 1
• Not approved for dementia-related psychosis without agitation 1
• Common adverse effects: dizziness, headache, insomnia, somnolence, UTIs 2, 6
• Cerebrovascular events, falls, extrapyramidal symptoms possible 6

Auvelity (Dextromethorphan-Bupropion)

FDA Status for Dementia:

• NOT FDA-approved for any dementia indication 7
• Approved only for major depressive disorder in adults 7
• Currently in Phase 3 trials for Alzheimer's disease agitation 2, 4—results pending

Why It's Being Studied:

• Dextromethorphan is an NMDA receptor antagonist and sigma-1 receptor agonist
• Bupropion inhibits CYP2D6 to increase dextromethorphan bioavailability 7
• Theoretical benefit for agitation, but no approved use or established efficacy data for dementia

Clinical Decision Algorithm

For Cognitive Decline/Dementia Treatment:

• Use NEITHER drug 8, 9
• Standard dementia treatment remains:
  • Cholinesterase inhibitors (donepezil, rivastigmine, galantamine) for mild-to-moderate AD, PDD, DLB, vascular dementia 9
  • Memantine for moderate-to-severe AD 9

For Agitation in Alzheimer's Dementia:

Step 1: Non-pharmacologic interventions FIRST 10, 11

• Identify and address triggers (pain, infection, environmental factors)
• Behavioral interventions, music therapy, structured activities
• Caregiver education and support

Step 2: If pharmacologic treatment needed:

• Rexulti is the ONLY FDA-approved option 1
• Start 0.5 mg daily, titrate slowly over 2 weeks to target 2 mg
• Do NOT use Auvelity—it lacks approval and evidence for this indication

Step 3: Set realistic expectations:

• Benefits are modest and take 6-12 weeks to manifest 3
• Consider bridging with PRN strategies during initial weeks (though Rexulti itself cannot be used PRN)
• Monitor for mortality risk, falls, cerebrovascular events 1, 6

Step 4: Reassess regularly:

• If no benefit after 12 weeks at adequate dose, consider discontinuation
• If psychosis emerges during treatment, unclear if continuation is appropriate—this remains an area of clinical uncertainty 3

Critical Pitfalls to Avoid

1. Do not use either drug to treat dementia or cognitive decline—they do not improve cognition 8, 9

2. Do not use Rexulti PRN—it requires daily maintenance dosing 1, 2

3. Do not use Auvelity for dementia agitation—it has no approval or evidence base for this indication 7

4. Do not skip non-pharmacologic interventions—these should always be first-line 10, 11

5. Do not ignore the mortality risk—all antipsychotics, including Rexulti, carry increased death risk in elderly dementia patients 1, 6

6. Do not expect rapid results with Rexulti—allow 6-12 weeks before declaring treatment failure 3

The Bottom Line

Rexulti is the only medication with FDA approval for dementia-related symptoms (specifically agitation in Alzheimer's), while Auvelity has no role in dementia treatment whatsoever. Neither treats the underlying dementia or cognitive decline. The approval of Rexulti represents a narrow indication with modest benefits and significant risks that must be carefully weighed against non-pharmacologic alternatives 10, 2, 4.