What are the recommended medications for treating psychosis in an elderly patient?

Treatment of Psychosis in Elderly Patients

For elderly patients with psychosis, risperidone 0.5-2.0 mg/day is the first-line antipsychotic medication, with quetiapine 50-150 mg/day as the preferred alternative, particularly in patients with Parkinson's disease or high risk of extrapyramidal symptoms. 1, 2

Critical First Step: Identify the Underlying Cause

Before initiating any antipsychotic, you must systematically investigate and treat reversible medical causes of psychosis that are common in elderly patients 1:

• Pain (often undertreated and cannot be verbally communicated in cognitively impaired patients) 1
• Infections (urinary tract infections, pneumonia) 1
• Metabolic disturbances (hypoxia, dehydration, hyperglycemia) 1
• Constipation and urinary retention 1
• Medication toxicity (especially anticholinergic medications like diphenhydramine, oxybutynin, cyclobenzaprine) 1

Medication Selection Algorithm

For Psychosis with Agitation/Delusions in Dementia

First-line: Risperidone 0.25-0.5 mg at bedtime, titrate to 0.5-2.0 mg/day 1, 2, 3

• Start at 0.25 mg in frail elderly patients 1
• Target dose typically 0.5-1.25 mg daily 1
• Risk of extrapyramidal symptoms increases above 2 mg/day 1, 3

Second-line alternatives:

• Quetiapine 12.5-25 mg twice daily, titrate to 50-150 mg/day 1, 2
  • More sedating with risk of orthostatic hypotension 1
  • Preferred in Parkinson's disease 4, 2
• Olanzapine 2.5 mg at bedtime, titrate to 5.0-7.5 mg/day 1, 2
  • Less effective in patients over 75 years 1
  • Avoid in diabetes, dyslipidemia, or obesity 2

For Psychosis in Alzheimer's Disease

First-line: Risperidone 0.5-3 mg/day 5

If risperidone fails: Low-dose haloperidol or olanzapine 5

If both fail: Quetiapine 5

Treatment-refractory cases: Clozapine (use with extreme caution due to anticholinergic properties worsening cognition) 5

For Psychosis in Parkinson's Disease

First-line: Quetiapine 12.5 mg twice daily, titrate slowly to 50-250 mg/day 4, 2, 5

Alternative: Clozapine (requires blood monitoring) 5

Avoid: Typical antipsychotics (haloperidol), risperidone, olanzapine due to severe extrapyramidal reactions 4, 2

For Late-Life Schizophrenia

First-line: Risperidone 1.25-3.5 mg/day 2

Second-line alternatives:

• Quetiapine 100-300 mg/day 2
• Olanzapine 7.5-15 mg/day 2
• Aripiprazole 15-30 mg/day 2

For Delusional Disorder

Only treatment recommended: An antipsychotic medication (specific agent not specified, but risperidone would be first-line based on general geriatric recommendations) 2

Medications to AVOID in Elderly Patients

• Typical antipsychotics (haloperidol, fluphenazine, thiothixene) as first-line therapy: 50% risk of tardive dyskinesia after 2 years of continuous use 1
• Clozapine in patients with diabetes, dyslipidemia, obesity, QTc prolongation, or congestive heart failure 2
• Olanzapine in patients with diabetes, dyslipidemia, obesity, or age >75 years 1, 2
• Ziprasidone in patients with QTc prolongation or congestive heart failure 2
• Anticholinergic medications (diphenhydramine) which worsen agitation and cognition 1

Critical Safety Discussion Required

Before initiating any antipsychotic, you must discuss with the patient (if feasible) and surrogate decision-maker: 1

• Increased mortality risk (1.6-1.7 times higher than placebo in elderly dementia patients) 1
• Cardiovascular risks (QT prolongation, dysrhythmias, sudden death, hypotension) 1
• Cerebrovascular adverse events 1
• Falls risk 1
• Metabolic effects (weight gain, diabetes, dyslipidemia) 1
• Extrapyramidal symptoms (tremor, rigidity, bradykinesia, tardive dyskinesia) 1

Dosing Principles for Elderly Patients

• Start low: Use 25-50% of the standard adult dose 1, 6
• Go slow: Titrate gradually while monitoring for adverse effects 1, 6
• Use lowest effective dose for the shortest possible duration 1
• Daily reassessment with in-person examination to evaluate ongoing need 1

Duration of Treatment

After successful response, attempt to taper and discontinue at: 2

• Delirium: 1 week 2
• Agitated dementia: Taper within 3-6 months to determine lowest effective maintenance dose 2
• Schizophrenia: Indefinite treatment at lowest effective dose 2
• Delusional disorder: 6 months to indefinitely at lowest effective dose 2

Monitoring Requirements

• Extrapyramidal symptoms (tremor, rigidity, bradykinesia, akathisia) 1, 7
• Falls and gait disturbances (walking problems reported in 39% of elderly patients on risperidone) 3
• Peripheral edema (reported in 16% of elderly patients on risperidone) 3
• Orthostatic hypotension (especially with quetiapine) 1, 4
• Sedation and cognitive worsening 1
• Metabolic parameters (weight, glucose, lipids) 1
• ECG for QTc prolongation (especially with haloperidol, ziprasidone) 1

Common Pitfalls to Avoid

• Continuing antipsychotics indefinitely without reassessment: 47% of patients continue receiving antipsychotics after discharge without clear indication 1
• Using antipsychotics for mild agitation: Reserve for severe symptoms that are dangerous or cause significant distress 1
• Failing to attempt non-pharmacological interventions first (unless emergency with imminent harm) 1
• Using benzodiazepines as first-line treatment: Risk of tolerance, addiction, cognitive impairment, and paradoxical agitation in 10% of elderly patients 1
• Prescribing typical antipsychotics as first-line: High risk of extrapyramidal symptoms and tardive dyskinesia 1, 7