How to manage a 75-year-old patient with a history (Hx) of antipsychotic medication use, currently on olanzapine (olanzapine) 2.5 mg, presenting with symptoms of Parkinsonism?

Management of Drug-Induced Parkinsonism in a 75-Year-Old on Olanzapine

The most appropriate management for this 75-year-old patient with drug-induced parkinsonism from olanzapine is to discontinue olanzapine and switch to quetiapine, starting at 25-50 mg daily. 1

Understanding Drug-Induced Parkinsonism

Drug-induced parkinsonism is a common adverse effect of antipsychotic medications, particularly in elderly patients. Olanzapine, despite being an atypical antipsychotic, can cause extrapyramidal symptoms (EPSEs) including parkinsonism, especially in older adults.

Risk Factors in This Patient:

• Advanced age (75 years)
• Current use of antipsychotic medication (olanzapine)
• History of antipsychotic medication use

Management Algorithm

Step 1: Discontinue or Switch the Offending Agent

• Discontinue olanzapine as it is clearly causing parkinsonism
• Switch to quetiapine which is the first-line antipsychotic for patients with Parkinson's disease or drug-induced parkinsonism 1
  • Starting dose: 25-50 mg daily
  • Titrate gradually as needed
  • Maximum dose: 200-300 mg daily in divided doses

Step 2: If Antipsychotic Treatment Must Continue

If psychiatric symptoms require continued antipsychotic treatment, consider these options in order of preference:

1. Quetiapine (25-50 mg daily initially) - first-line option for patients with parkinsonism 1
2. Clozapine (6.25-12.5 mg daily initially) - effective but requires blood monitoring
3. Aripiprazole (5 mg daily initially) - may be considered but with caution

Step 3: Consider Antiparkinsonian Medication

If parkinsonism symptoms persist despite switching antipsychotics:

• For younger patients: Anticholinergic agents (e.g., trihexyphenidyl)
• For elderly patients like this one: Amantadine (100 mg daily) is better tolerated than anticholinergics 2

Important Considerations

Avoid These Medications:

• Olanzapine - already causing parkinsonism in this patient
• Risperidone - high risk of EPSEs, especially at doses >2 mg daily
• Haloperidol and other typical antipsychotics - highest risk of EPSEs
• Metoclopramide - dopamine antagonist that worsens parkinsonism

Monitoring:

• Assess for improvement in parkinsonian symptoms within 2-4 weeks of medication change
• Monitor for continued psychiatric symptom control
• Watch for orthostatic hypotension and sedation with quetiapine, especially in this elderly patient

Dosing Considerations for Elderly:

• Start at lower doses (25-50 mg for quetiapine)
• Titrate more slowly than in younger adults
• Use the lowest effective dose to minimize side effects

Evidence Quality and Rationale

The ESMO guidelines clearly state not to use antipsychotics in patients with Parkinson's disease or dementia with Lewy bodies due to risk of EPSEs 3. Expert consensus identifies quetiapine as the first-line antipsychotic for patients with Parkinson's disease 1, with studies showing it causes minimal worsening of motor symptoms compared to other antipsychotics.

While olanzapine has been studied in Parkinson's disease psychosis, controlled trials showed significant worsening of motor symptoms 4, making it inappropriate for this patient who already has drug-induced parkinsonism.

The FDA label for olanzapine specifically warns about the risk of tardive dyskinesia and other movement disorders, particularly in elderly patients 5, further supporting the recommendation to switch medications.

Common Pitfalls to Avoid

1. Adding anticholinergic medications while continuing olanzapine - This approach masks symptoms without addressing the cause and increases anticholinergic burden in an elderly patient

2. Abrupt discontinuation of olanzapine - May cause withdrawal symptoms; taper gradually while cross-titrating to quetiapine

3. Using high-dose quetiapine - Start low (25-50 mg) and titrate slowly to minimize sedation and orthostatic hypotension

4. Ignoring underlying psychiatric condition - Ensure the alternative antipsychotic adequately treats the original psychiatric indication

By following this approach, you can effectively manage drug-induced parkinsonism while maintaining appropriate treatment for the underlying psychiatric condition requiring antipsychotic therapy.