In an 85-year-old woman taking mirtazapine (Remeron) 30 mg nightly who has sundowning, should the dose be increased and what alternative or adjunctive treatment options are appropriate?

Do Not Increase Remeron for Sundowning

She is already at the maximum recommended dose for sleep/sedation (30 mg), and increasing mirtazapine will not address sundowning—a behavioral phenomenon requiring non-pharmacological interventions first, followed by targeted antipsychotic therapy if severe. 1, 2, 3

Why Not Increase Mirtazapine?

The FDA-approved dosing for mirtazapine ranges from 15-45 mg daily for depression 3. However, for sleep and sedation benefits specifically, 30 mg at bedtime is the maximum effective dose 1. The sedating properties of mirtazapine actually decrease at higher doses due to increased noradrenergic activity 1. One study showed potential benefit from increasing 15 mg to 30 mg in non-responders, but no benefit beyond 30 mg 4.

More importantly, sundowning is not primarily a sleep disorder—it's a complex neuropsychiatric phenomenon involving agitation, confusion, and behavioral disturbances in the late afternoon/evening 5, 6, 7. Mirtazapine addresses insomnia and appetite but does not target the core symptoms of sundowning.

Treatment Algorithm for Sundowning

Step 1: Non-Pharmacological Interventions (FIRST-LINE)

• Environmental modifications: Increase lighting in late afternoon/evening, reduce shadows and noise
• Structured activities: Schedule engaging activities during high-risk hours (4-8 PM)
• Sleep hygiene: Ensure adequate daytime light exposure, avoid daytime napping
• Reorientation techniques: Use clocks, calendars, familiar objects
• Caregiver education: Train family on redirection and de-escalation strategies 1, 2

Step 2: Identify and Treat Reversible Causes

• Pain: Uncontrolled pain worsens agitation
• Delirium: Rule out infection, metabolic disturbances, medication toxicity
• Medication review: Discontinue or reduce anticholinergics, benzodiazepines, steroids 2
• Depression/anxiety: Optimize current antidepressant therapy (she's already on mirtazapine)
• Sleep-disordered breathing: Consider evaluation if snoring/apnea suspected 2

Step 3: Pharmacological Options for Refractory Agitation

If severe agitation persists despite above measures:

First-line antipsychotics (start low, go slow in elderly):

• Quetiapine 12.5-25 mg in late afternoon (2.5-5 mg at bedtime per guidelines, but can give earlier for sundowning) 2, 8, 2
• Olanzapine 2.5 mg in late afternoon 2, 8, 2

Alternative if antipsychotics contraindicated:

• Trazodone 25-50 mg in late afternoon (though primarily for insomnia) 9, 2

Avoid in elderly patients:

• Benzodiazepines (lorazepam, etc.): Increase fall risk, cognitive impairment, and can paradoxically worsen agitation 2, 10, 11
• Haloperidol: Higher risk of extrapyramidal symptoms in elderly 8

Critical Caveats

1. Antipsychotics carry black box warning for increased mortality in elderly with dementia—use only when behavioral symptoms pose serious risk and non-pharmacological interventions have failed 2, 11

2. Benzodiazepines are particularly dangerous in this population: 7-18 times more likely to cause falls, fractures, cognitive decline, and can worsen delirium 10, 11

3. If underlying dementia with Lewy bodies, consider cholinesterase inhibitor (donepezil) which has shown benefit for sundowning in case reports 12

4. Monitor for delirium: Sundowning can overlap with or mask delirium—use DSM criteria to distinguish 2

5. Gradual withdrawal if starting antipsychotics: These should be time-limited trials (weeks to months), not indefinite therapy 11

Practical Approach for This Patient

1. Keep mirtazapine at 30 mg at bedtime—do not increase
2. Implement environmental interventions immediately: Increase afternoon lighting, structured activities 4-8 PM, avoid late-day stimulation
3. Rule out delirium: Check for infection, review all medications for anticholinergic burden
4. If severe agitation endangers patient/caregivers: Start quetiapine 12.5 mg at 4 PM, titrate to 25 mg if needed after 3-5 days
5. Reassess weekly: Attempt to taper/discontinue antipsychotic after 4-8 weeks if symptoms improve