Can I discontinue Risperdal (risperidone) and switch back to Loxapine in an 85-year-old female patient with Alzheimer's disease and refractory visual hallucinations?

Switching from Risperidone to Loxapine for Visual Hallucinations in Alzheimer's Disease

Yes, you can discontinue risperidone and switch back to loxapine for this 85-year-old patient with Alzheimer's disease and refractory visual hallucinations, as loxapine was previously effective for controlling her symptoms while risperidone has proven ineffective both currently and in past trials. 1

Rationale for Switching

• The patient has a documented history of visual hallucinations partially controlled with loxapine (10 mg) from 2021 to October 2024
• Current risperidone trial (0.25 mg at bedtime) is ineffective, consistent with previous failed trials
• Previous trials of quetiapine were also ineffective
• Patient has significant BPSD with psychotic features causing distress (terror, nocturnal wandering, police calls)

Switching Strategy

For switching from risperidone to loxapine, implement a gradual approach:

1. Week 1: Continue risperidone 0.25 mg while initiating loxapine at 5 mg daily
2. Week 2: Discontinue risperidone completely while increasing loxapine to 10 mg daily (previously effective dose)
3. Week 3 and beyond: Maintain loxapine at 10 mg daily, adjusting as needed

This gradual approach is supported by evidence showing that gradual discontinuation of antipsychotics results in lower rates of treatment discontinuation and better outcomes 2, 3.

Clinical Considerations

Efficacy for BPSD

• While guidelines often recommend atypical antipsychotics as first-line for BPSD, individual patient response should guide treatment 1
• This patient has documented partial response to loxapine but not to risperidone or quetiapine
• The patient's hallucinations may have multiple contributing factors:
  • Alzheimer's disease with vascular contribution
  • Visual impairment from macular degeneration (possible Charles Bonnet syndrome)

Safety Considerations

• Monitor closely for extrapyramidal symptoms (EPS), as elderly patients are more susceptible 1
• Perform baseline ECG and follow-up monitoring to assess QTc prolongation risk 1
• Implement fall prevention strategies given the patient's age and cognitive impairment 1
• Start with a low dose (5 mg) of loxapine before returning to the previously effective dose (10 mg)

Monitoring Plan

• Assess effectiveness of loxapine for controlling visual hallucinations within 2-4 weeks
• Monitor for side effects, particularly sedation, orthostatic hypotension, and EPS
• Regular medical evaluation every 3 months to assess continued need for antipsychotic therapy 1
• Consider cognitive reassessment (MMSE, MoCA) to track disease progression

Managing Potential Adverse Effects

• If akathisia develops, consider dose reduction of loxapine 1
• For extrapyramidal symptoms, consider adding an anticholinergic agent temporarily
• If excessive sedation occurs, adjust timing of administration to bedtime
• Continue to address potential reversible causes of agitation (pain, constipation, etc.) 1

Non-Pharmacological Approaches

While implementing the medication switch, simultaneously reinforce:

• Structured daily routines to reduce anxiety and confusion
• Adequate lighting to minimize visual misperceptions
• Caregiver education about managing hallucinations
• Regular reassurance and reality orientation

The evidence supports your clinical decision to return to loxapine, which previously provided partial control of the patient's hallucinations, especially given the documented ineffectiveness of risperidone and other atypical antipsychotics in this specific patient.