Management of Dyskinesias in Parkinson's Disease and Tardive Dyskinesia
Critical First Step: Distinguish the Type of Dyskinesia
The management of dyskinesias depends entirely on whether you are treating levodopa-induced dyskinesia in Parkinson's disease versus tardive dyskinesia from antipsychotic exposure—these require opposite treatment approaches and confusing them can cause significant harm. 1
Key Diagnostic Features
Levodopa-induced dyskinesia:
- Occurs in Parkinson's disease patients receiving dopaminergic therapy (particularly levodopa) 2
- Presents as choreiform movements that correlate with medication timing 3
- Affects approximately 30-40% of Parkinson's patients 3
- May worsen with increased dopaminergic medication 2
Tardive dyskinesia:
- Develops after at least 3 months of exposure to dopamine receptor blocking agents (antipsychotics, antiemetics) 1, 4
- Typically presents with orofacial movements: lip smacking, puckering, chewing, or tongue protrusion 1, 4
- May persist or worsen even after stopping the causative medication 1, 5
- Affects 20-35% of antipsychotic users 4
Management of Tardive Dyskinesia
First-Line Treatment
For moderate to severe tardive dyskinesia, initiate treatment with a VMAT2 inhibitor (valbenazine or deutetrabenazine) as first-line pharmacotherapy. 6, 1 These agents have Level 1A evidence demonstrating robust efficacy with FDA approval based on randomized controlled trials. 6
- Valbenazine 80 mg showed statistically significant improvement in AIMS dyskinesia total score compared to placebo at 6 weeks 7
- The treatment effect was sustained through 48 weeks of continued therapy 7
Medication Adjustment Strategy
If clinically feasible, gradually withdraw the offending antipsychotic medication. 6, 1 This remains the primary intervention when the underlying psychiatric condition allows. 6
If continued antipsychotic therapy is necessary, switch to clozapine, which has the lowest risk profile for movement disorders. 6, 1 Alternatively, consider other atypical antipsychotics with lower D2 affinity. 1
Critical Pitfall to Avoid
Never use anticholinergic medications (benztropine, trihexyphenidyl) for tardive dyskinesia—these are contraindicated and will actually worsen the condition. 6, 1 This is a common and dangerous error, as anticholinergics are appropriate for drug-induced parkinsonism but harmful in tardive dyskinesia. 1
Monitoring
- Use the Abnormal Involuntary Movement Scale (AIMS) to assess severity and track treatment response 6, 1
- Monitor at least every 3-6 months 1, 6
- Document baseline movements before initiating any antipsychotic therapy to avoid mislabeling pre-existing movements as tardive dyskinesia 1
Management of Levodopa-Induced Dyskinesia in Parkinson's Disease
Medication Adjustment Approach
Reduce the dose of levodopa or other dopaminergic medications to ameliorate dyskinesia. 2 This is the first-line approach for managing levodopa-induced dyskinesia. 2
Consider switching to continuous drug delivery strategies to reduce dyskinesia intensity. 3 Pulsatile dopaminergic stimulation using short-acting drugs leads to dyskinesia induction, while more constant drug delivery dramatically reduces dyskinesia. 3
Surgical Treatment Options
Deep brain stimulation of the subthalamic nucleus (STN DBS) is highly effective for treating levodopa-induced dyskinesias by allowing significant reduction in dopaminergic medications. 8 This should be considered when medication adjustments are insufficient.
If the primary goal is reduction of "on" medication dyskinesias without medication reduction, target the globus pallidus internus (GPi) instead of STN. 8
Special Consideration: Paroxysmal Kinesigenic Dyskinesia
Do not confuse levodopa-induced dyskinesia with paroxysmal kinesigenic dyskinesia (PKD), which is a completely separate condition triggered by sudden movements. 8 PKD responds dramatically to sodium channel blockers like carbamazepine or oxcarbazepine, not dopaminergic manipulation. 9, 10
PKD Diagnostic Features:
- Attacks triggered by sudden movement, lasting less than 1 minute 9
- Excellent response to low-dose carbamazepine/oxcarbazepine 9, 10
- Often associated with PRRT2 gene mutations 9
- Can be confirmed with high-knee exercise test 9
Prevention Strategies for Tardive Dyskinesia
Use atypical antipsychotics preferentially, as they carry significantly lower risk than typical antipsychotics. 1 Up to 50% of youth receiving typical neuroleptics may experience some form of tardive or withdrawal dyskinesia. 1
Provide adequate informed consent regarding tardive dyskinesia risk when prescribing any antipsychotic. 1 Patients must understand that tardive dyskinesia may persist indefinitely even after medication discontinuation, making prevention paramount. 1
Perform baseline assessment of abnormal movements before starting antipsychotic therapy. 1 This documentation is crucial to avoid mislabeling pre-existing movements as treatment-emergent tardive dyskinesia. 1