How are extrapyramidal side effects managed?

Management of Extrapyramidal Side Effects

Extrapyramidal side effects (EPS) should be managed with specific medications based on the type of symptoms, with anticholinergic agents being the first-line treatment for acute dystonia, benztropine for parkinsonian symptoms, and beta-blockers for akathisia.

Types of Extrapyramidal Side Effects

Extrapyramidal side effects are common adverse reactions to antipsychotic medications, particularly conventional antipsychotics. They include:

1. Acute dystonia: Abnormal muscle spasms and postures, usually occurring 3-5 days after starting antipsychotic therapy or increasing dosage 1
2. Pseudoparkinsonism: Resembles idiopathic Parkinson's disease with tremor, rigidity, and bradykinesia, typically appearing within the first 3 months of treatment 1
3. Akathisia: Characterized by subjective feelings of restlessness and anxiety with objective signs of motor activity (inability to sit still), appearing days to weeks after antipsychotic exposure 1
4. Tardive dyskinesia: Late-onset involuntary movements, particularly affecting the face and mouth

Treatment Algorithm by EPS Type

1. Acute Dystonia

• First-line: Anticholinergic medications administered immediately
  • Benztropine: 1-2 mg IM/IV (can repeat in 30 minutes if needed), then 1-2 mg PO twice daily 2
  • Maximum dose: 6 mg daily 2
• Alternative: Benzodiazepines (e.g., lorazepam 0.5-2 mg) 2, 1

2. Pseudoparkinsonism

• First-line: Lower the antipsychotic dosage if clinically feasible
• Second-line: Add anticholinergic agent
  • Benztropine: 1-2 mg daily, divided into 1-2 doses 2
• Third-line: Consider amantadine 100 mg twice daily
• Fourth-line: Switch to a lower-potency or atypical antipsychotic 1

3. Akathisia

• First-line: Beta-blockers
  • Propranolol: 10-30 mg 2-3 times daily (use with caution in patients with asthma, diabetes, or cardiovascular disease) 2
• Second-line: Benzodiazepines (e.g., lorazepam 0.5-2 mg as needed) 2
• Third-line: Anticholinergic agents (less effective for akathisia than for other EPS) 1
• Fourth-line: Reduce antipsychotic dose or switch to an atypical antipsychotic 1

Prevention Strategies

1. Use lowest effective dose of antipsychotic medication 1
2. Consider atypical antipsychotics which have lower risk of EPS than conventional antipsychotics 3
   • Risperidone appears to be the most likely among atypical agents to produce EPS 3
   • Clozapine has the lowest risk but has significant other side effects including agranulocytosis 3
3. Avoid antipsychotic polytherapy as it increases risk of EPS due to higher cumulative doses 4
4. Selective prophylaxis for high-risk patients:
   • Young males
   • First episode patients
   • Previous history of EPS
   • High-potency antipsychotic use 5

Important Considerations

• Do not use anticholinergic agents routinely for prophylaxis as this can add unnecessary side effect burden 5
• If prophylactic anticholinergic treatment is initiated, discontinue after approximately two weeks 5
• Long-term use of anticholinergic medications is not therapeutically beneficial and should be avoided 5
• Regular monitoring for abnormal movements using standardized scales like the Abnormal Involuntary Movement Scale (AIMS) every 3-6 months 2
• Special populations:
  • Elderly patients are more susceptible to both EPS and anticholinergic side effects 6
  • Patients with Parkinson's disease are extremely sensitive to antipsychotic effects; consider pimavanserin, clozapine, or quetiapine if antipsychotics are needed 2

Common Pitfalls to Avoid

1. Misdiagnosis of akathisia as anxiety or agitation, leading to inappropriate dose increases that worsen symptoms
2. Prolonged anticholinergic use causing cognitive impairment, urinary retention, and constipation
3. Failure to recognize EPS caused by non-antipsychotic medications (some antidepressants, lithium, anticonvulsants, antiemetics) 7
4. Overlooking the emergence of tardive dyskinesia during long-term treatment
5. Using doses of atypical antipsychotics higher than recommended, which increases EPS risk despite their "atypical" status 5

By following this structured approach to managing extrapyramidal side effects, clinicians can effectively reduce patient suffering and improve medication adherence while maintaining control of psychiatric symptoms.