What are the treatment options for Extrapyramidal Symptoms (EPS) induced by antipsychotic medications?

Management of Extrapyramidal Symptoms (EPS) Induced by Antipsychotics

The first-line treatment for antipsychotic-induced extrapyramidal symptoms is dose reduction of the causative antipsychotic medication, switching to an atypical antipsychotic with lower EPS risk, or adding appropriate symptomatic medication based on the specific type of EPS. 1

Types of Extrapyramidal Symptoms

Antipsychotic-induced EPS can be categorized into several distinct syndromes:

1. Acute Dystonia

   • Abnormal muscle contractions and postures
   • Usually occurs within first few days of treatment or dose increase
   • More common in young males

2. Parkinsonism

   • Resembles idiopathic Parkinson's disease
   • Rigidity, tremor, bradykinesia
   • Typically appears within first three months of treatment

3. Akathisia

   • Subjective restlessness and objective motor restlessness
   • Appears days to weeks after antipsychotic initiation
   • Often difficult to manage

Treatment Algorithm by EPS Type

1. Acute Dystonia

• First-line: Anticholinergic medications
  • Benztropine 1-2 mg IM/IV/PO (maximum 6 mg daily) 1
  • Response usually occurs within minutes with parenteral administration
• Alternative: Benzodiazepines (e.g., lorazepam 0.5-2 mg) 1

2. Drug-Induced Parkinsonism

• First-line: Reduce antipsychotic dose if clinically feasible 1, 2
• Second-line: Add anticholinergic agent
  • Benztropine 1-2 mg daily (start at 0.5 mg in elderly) 1
• Third-line: Switch to atypical antipsychotic with lower EPS risk
  • Quetiapine (100-300 mg/day) or olanzapine (7.5-15 mg/day) 1
• Alternative: Amantadine 100-300 mg/day 2

3. Akathisia

• First-line: Beta-blockers
  • Propranolol 10-30 mg two to three times daily 1
  • Use with caution in patients with asthma, diabetes, or cardiovascular disease
• Second-line: Benzodiazepines
  • Lorazepam 0.5-2 mg as needed 1
• Third-line: Anticholinergics (less effective for akathisia than for other EPS)
• Fourth-line: Consider switching to antipsychotic with lower akathisia risk

Antipsychotic Selection to Minimize EPS

When selecting antipsychotics to minimize EPS risk:

1. Lowest EPS risk: Clozapine and quetiapine 3
2. Moderate EPS risk: Olanzapine, aripiprazole
3. Higher EPS risk among atypicals: Risperidone 3

The incidence of EPS is significantly higher with typical antipsychotics (46%) compared to atypical antipsychotics (12%) 4. However, even atypical antipsychotics can cause EPS at higher doses or in vulnerable patients.

Special Populations

Elderly Patients

• Start with lower doses of anticholinergics (benztropine 0.5 mg)
• More susceptible to anticholinergic side effects (confusion, urinary retention, constipation)
• Titrate medications slowly 1

Parkinson's Disease Patients

• Extremely sensitive to antipsychotic effects
• If antipsychotics needed, consider:
  1. Pimavanserin (first-line)
  2. Clozapine (second-line)
  3. Quetiapine (third-line) 1

Monitoring

• Regular assessment for abnormal movements using standardized scales like AIMS every 3-6 months 1
• Monitor for anticholinergic side effects (dry mouth, blurred vision, constipation, urinary retention)
• For patients on beta-blockers, monitor blood pressure and heart rate
• For patients switched to atypical antipsychotics, monitor metabolic parameters (blood glucose, lipids, weight) 1

Prevention Strategies

• Use the lowest effective dose of antipsychotic medication
• Consider atypical antipsychotics with lower EPS risk for long-term treatment
• Avoid routine prophylactic use of anticholinergics unless patient has high risk for dystonia
• Educate patients about early signs of EPS and importance of reporting symptoms

Common Pitfalls

1. Misdiagnosis of akathisia as anxiety or agitation, leading to inappropriate dose increases that worsen symptoms
2. Prolonged anticholinergic use when no longer needed, causing unnecessary side effects
3. Failure to recognize tardive dyskinesia early, which may become irreversible
4. Overlooking drug interactions that may increase antipsychotic levels and EPS risk
5. Assuming all atypical antipsychotics have the same EPS risk profile 3

By following this structured approach to managing antipsychotic-induced EPS, clinicians can minimize the impact of these troublesome side effects while maintaining effective control of psychiatric symptoms.