How are extrapyramidal symptoms managed?

Management of Extrapyramidal Symptoms

For acute dystonia, administer benztropine 1-2 mg IM/IV immediately, which typically relieves symptoms within minutes, then maintain on oral anticholinergics 1-2 mg twice daily to prevent recurrence. 1, 2

Immediate Treatment Based on EPS Type

Acute Dystonia (Sudden Muscle Spasms)

• Administer benztropine 1-2 mg IM/IV as first-line treatment, which usually provides rapid relief 1, 2
• Alternative: diphenhydramine 25-50 mg IM/IV can be used and has shown prompt response in severe cases 3
• After acute treatment, maintain on oral benztropine 1-2 mg twice daily to prevent recurrence 2
• Continue anticholinergic medications even after antipsychotic discontinuation to prevent delayed symptom emergence 1

Drug-Induced Parkinsonism (Bradykinesia, Tremor, Rigidity)

• First strategy: reduce the antipsychotic dose 1
• Second strategy: switch to an atypical antipsychotic with lower EPS risk (quetiapine, olanzapine, clozapine) 1
• If dose reduction and switching fail, add benztropine 1-4 mg once or twice daily, individualized to patient response 2
• Some patients require more than the standard dose range, while others need less 2

Akathisia (Restlessness and Motor Agitation)

• Reduce antipsychotic dose first 4
• If dose reduction is not practical or effective, lipophilic beta-blockers (propranolol or metoprolol) are most effective 4
• Alternative options include anticholinergics or benzodiazepines 4, 5
• Critical pitfall: Akathisia is often misinterpreted as anxiety or psychotic agitation, leading to inappropriate dose increases that worsen symptoms 1

Tardive Dyskinesia (Involuntary Movements from Long-term Use)

• Reduce antipsychotic dose or switch medication 1
• Maintain antipsychotic only if patient is in complete remission and medication change would precipitate relapse 1
• Prevention is key: Risk is approximately 5% per year in young patients with chronic use 1

Prevention Strategies

Medication Selection

• Prefer atypical antipsychotics with lowest EPS risk: quetiapine (lowest), followed by aripiprazole, olanzapine, then risperidone 6
• Avoid high-potency typical antipsychotics (haloperidol) which carry the highest EPS risk 1
• In first-episode psychosis, use low doses within the limits of EPS: maximum 4-6 mg haloperidol equivalent 7

Dosing Strategy

• Use the lowest effective dose and avoid rapid dose escalation 1
• For risperidone specifically, doses above 2 mg/day significantly increase EPS risk 8
• In elderly patients, start risperidone at 0.25 mg daily; doses exceeding 2-3 mg/day markedly increase EPS 8, 6
• Increase doses only at widely spaced intervals (14-21 days after initial titration) if response is inadequate 7

Monitoring

• Regular monitoring for early signs of EPS is essential 1
• Young males are at particularly high risk for acute dystonia 1
• Children, adolescents, and elderly patients are at higher overall risk for all EPS types 1

Anticholinergic Medication Dosing

Benztropine (First-line for Most EPS)

• Acute dystonia: 1-2 mg IM/IV for immediate relief 2
• Maintenance for drug-induced EPS: 1-4 mg once or twice daily orally 2
• Initiate with low doses and increase gradually in 0.5 mg increments at 5-6 day intervals 2
• Maximum dose: 6 mg daily 2
• Elderly and thin patients cannot tolerate large doses 2

Trihexyphenidyl (Alternative Anticholinergic)

• For drug-induced parkinsonism: Total daily dose usually 5-15 mg, though some patients controlled with as little as 1 mg daily 9
• Start with 1 mg on first day, increase by 2 mg increments every 3-5 days 9
• Divide total daily dose into 3-4 portions, preferably at mealtimes 9

Important Cautions and Pitfalls

When NOT to Use Anticholinergics Routinely

• Anticholinergics should not be used routinely for preventing EPS but reserved for treatment of significant symptoms when dose reduction and switching strategies have failed 1
• Prophylactic use in high-risk patients may be appropriate for acute dystonia prevention, but long-term prophylaxis is controversial 4

Anticholinergic Side Effects

• Benztropine can cause delirium, drowsiness, and paradoxical agitation 1
• In elderly patients, avoid anticholinergics when possible due to increased delirium risk 6

Withdrawal Considerations

• After 1-2 weeks of anticholinergic treatment for transient EPS, withdraw the drug to determine continued need 2
• If EPS recurs, reinstitute anticholinergic therapy 2
• Certain slowly-developing drug-induced EPS may not respond to anticholinergics 2

Special Situations

• For metoclopramide-induced EPS (especially in pregnancy): Immediately withdraw the drug upon symptom reporting 1
• Neuroleptic malignant syndrome: Use bromocriptine and anticholinergics; dantrolene has not shown efficacy in pediatric cases 1
• When EPS develops soon after starting antipsychotics, symptoms are likely transient and may resolve with brief anticholinergic treatment 2