What is the best treatment approach for a patient with Parkinson's disease experiencing dyskinesia, considering their overall health and medical history?

Management of Parkinson's Disease-Related Dyskinesia

For Parkinson's disease patients experiencing levodopa-induced dyskinesia, the primary treatment strategy is to reduce individual levodopa doses while adding amantadine, which is the only medication proven to reduce established dyskinesia without compromising motor benefit. 1, 2, 3

Initial Assessment and Classification

The first critical step is identifying the dyskinesia subtype based on timing relative to levodopa dosing, as treatment differs substantially 3:

• Peak-dose dyskinesia (most common): Choreiform movements occurring when levodopa levels are highest 2, 3
• Diphasic dyskinesia: Occurs during rising and falling levodopa levels, most difficult to treat 3
• Off-period dystonia: Typically early morning dystonia when levodopa levels are lowest 4, 3

Treatment Algorithm for Peak-Dose Dyskinesia

Medication Adjustments

The goal is maintaining plasma levodopa concentrations above the therapeutic threshold but below the dyskinesia threshold 4:

• Reduce individual levodopa doses and increase dosing frequency to maintain more stable dopamine stimulation 1, 4, 3
• Add amantadine as the only evidence-based anti-dyskinetic agent that doesn't reduce antiparkinsonian benefit 2, 3
• Consider switching to or combining standard and sustained-release levodopa formulations to smooth plasma levels 4, 5

Optimization Strategies

• Take levodopa at least 30 minutes before meals to avoid protein interactions that reduce absorption 1, 6
• Implement protein redistribution diet (low-protein breakfast/lunch, normal protein at dinner) to improve motor function and increase "ON" time 1
• Separate levodopa from calcium and iron supplements by at least 2 hours to optimize absorption 6

Common Pitfall

Monitor for complications of protein redistribution including weight loss, micronutrient deficits, and paradoxically worsened dyskinesias 1. Avoid strict low-protein diets as they lack evidence and cause nutritional deficiencies 1, 6.

Treatment of Off-Period Dystonia

• Add sustained-release levodopa before bedtime to prevent early morning dystonia 4
• Baclofen can be effective for off-period dystonia 3
• Botulinum toxin injections for severe, focal dystonia 4, 3
• Liquid levodopa or apomorphine injection immediately before dystonic posture onset 4

Treatment of Diphasic Dyskinesia

This is the most challenging subtype, particularly in young-onset PD patients 3:

• Treatment approach paradoxically resembles peak-dose dyskinesia management despite different pathophysiology 4
• Apomorphine or liquid levodopa may help prevent diphasic episodes 4
• Many patients ultimately require deep brain stimulation for adequate control 3

Advanced Therapeutic Options

Deep Brain Stimulation

When dyskinesias remain troublesome despite medication optimization, DBS should be considered 7, 1:

• For primary goal of reducing "ON" medication dyskinesias without medication reduction: Target GPi 7
• For patients with cognitive concerns: Prefer GPi over STN due to better cognitive outcomes, particularly regarding processing speed and working memory 7, 1
• For patients with depression concerns: Prefer GPi over STN due to lower risk of mood disturbance 7
• Both STN and GPi DBS provide equivalent motor score improvements and quality of life benefits 7

Important DBS Caveat

Deep brain stimulation has not demonstrated improved control of REM sleep behavior disorder dream enactment in PD patients, contrary to what might be expected 1.

Essential Monitoring Requirements

Nutritional Surveillance

• Monitor vitamin B12, folate, and homocysteine levels as levodopa causes hyperhomocysteinemia requiring higher B vitamin supplementation 1, 6
• Regular weight monitoring as increasing levodopa doses over time are associated with higher malnutrition risk 1, 6
• Watch for medication side effects affecting nutrition: nausea, vomiting, constipation, anorexia, dry mouth 1

For Constipation Management

Fermented milk with probiotics and prebiotic fiber, combined with increased water and fiber intake 1, 6

Special Population: Tube-Fed Patients

Interrupt enteral nutrition for at least 1 hour before and 30-40 minutes after levodopa administration to prevent protein interference with absorption 1, 6

Medications to Avoid or Adjust

• Consider stopping selegiline as discontinuation may reduce dyskinesias 4
• Reduce or stop dopamine agonist if dyskinesias are troublesome, though this must be balanced against motor control 4