How should new choreo‑athetoid movements be managed in an 80‑year‑old patient with Parkinson disease treated with carbidopa/levodopa and dementia treated with donepezil?

Management of New Choreoathetoid Movements in an 80-Year-Old with Parkinson's Disease on Carbidopa-Levodopa and Dementia on Donepezil

The new choreoathetoid movements are most likely levodopa-induced dyskinesias, and you should reduce the carbidopa-levodopa dose while optimizing medication timing and protein intake to maintain motor control. 1

Immediate Assessment and Medication Adjustment

Reduce Levodopa Dose

• Lower the total daily dose of carbidopa-levodopa by 10-25% as the first-line intervention, as choreoathetoid movements represent peak-dose dyskinesias from excessive dopaminergic stimulation. 1
• Divide the reduced total daily dose into more frequent, smaller doses throughout the day to minimize plasma level fluctuations that trigger dyskinesias. 1
• Continue levodopa as the sole antiparkinsonian agent—do not add dopamine agonists, anticholinergics, amantadine, or selegiline in this elderly patient with dementia, as these agents carry high risk of worsening confusion, hallucinations, and psychosis. 2, 3

Optimize Levodopa Absorption

• Ensure carbidopa-levodopa is taken at least 30 minutes before meals to maximize absorption and reduce erratic plasma levels that contribute to dyskinesias. 4, 2
• Implement protein redistribution: low-protein breakfast and lunch with normal protein intake only at dinner, which improves motor function and increases "ON" time duration while potentially reducing dyskinesia severity. 5, 4
• Target daily protein intake of 0.8-1.0 g/kg body weight to meet nutritional requirements while optimizing levodopa efficacy. 5, 4

Donepezil Management

Continue Cholinesterase Inhibitor

• Maintain donepezil therapy, as cholinesterase inhibitors improve cognition in Parkinson's disease dementia and may help alleviate psychiatric symptoms including hallucinations and delusions without worsening motor function. 3, 6
• Monitor for potential worsening of parkinsonism with donepezil, though this occurs in only a minority of patients and typically responds to levodopa dose adjustment. 7
• Donepezil does not cause or worsen dyskinesias and should not be discontinued due to the new movement disorder. 7

Critical Monitoring Parameters

Nutritional and Metabolic Surveillance

• Monitor homocysteine and vitamin B status (B6, B12, folate), as levodopa causes hyperhomocysteinemia and increases vitamin B requirements, particularly important in elderly patients. 4, 2
• Track body weight regularly, as weight loss is associated with disease progression and increased levodopa requirements. 4, 2
• Ensure adequate hydration: target 1.6 L daily for women and 2.0 L for men. 2

Medication Timing with Supplements

• Separate calcium and iron supplements from levodopa doses by at least 2 hours to prevent chelation and reduced bioavailability. 4, 2

Common Pitfalls to Avoid

• Do not add dopamine agonists to control motor symptoms, as they markedly increase risk of psychosis, confusion, and impulse control disorders in elderly patients with dementia. 2, 3
• Do not use typical or atypical antipsychotics (except quetiapine or clozapine if absolutely necessary for severe psychosis), as neuroleptic sensitivity occurs in up to 50% of patients with Parkinson's disease dementia and can cause severe psychomotor adverse reactions. 3
• Do not discontinue donepezil in response to dyskinesias, as the cholinesterase inhibitor is not causative and provides important cognitive benefits. 3, 7
• Do not implement strict low-protein diets, as there is no evidence supporting this approach and it risks malnutrition in elderly patients. 5

If Dyskinesias Persist Despite Dose Reduction

• Consider switching to extended-release carbidopa-levodopa formulations at night to provide more stable plasma levels. 6
• Evaluate for gastrointestinal dysfunction (delayed gastric emptying, constipation) that can cause erratic levodopa absorption and contribute to motor fluctuations and dyskinesias. 5, 4
• Reassess total daily levodopa requirements, as the appearance of dyskinesias may indicate the patient is receiving more dopaminergic stimulation than needed for adequate motor control. 1