How to manage Extrapyramidal Symptoms (EPS) in patients taking antipsychotic medication?

Management of Extrapyramidal Symptoms (EPS) in Patients Taking Antipsychotic Medication

When EPS occurs with antipsychotic treatment, immediately reduce the antipsychotic dose or switch to an atypical agent with lower EPS risk (olanzapine, quetiapine, or clozapine), reserving anticholinergic medications like benztropine only for acute dystonic reactions or when dose reduction fails. 1, 2

Immediate Assessment and Type Identification

When a patient presents with EPS, first identify which specific syndrome is present, as management differs by type 1:

• Acute dystonia: Sudden spastic muscle contractions (neck, eyes with oculogyric crisis, torso), typically occurring within the first few days of treatment, particularly in young males 1
• Drug-induced parkinsonism: Bradykinesia, tremors, and rigidity appearing within the first three months 1
• Akathisia: Subjective restlessness with objective motor activity (pacing, inability to sit still), often misinterpreted as anxiety or psychotic agitation, appearing days to weeks after initiation 1
• Tardive dyskinesia: Involuntary movements from long-term use, developing at approximately 5% per year in young patients 1

Primary Management Strategy: Medication Adjustment

First-Line Approach: Dose Reduction or Medication Switch

The preferred initial strategy is to reduce the antipsychotic dose or switch to an atypical antipsychotic rather than adding anticholinergic agents. 1, 2

For patients on haloperidol or other high-potency typical antipsychotics 2:

• Decrease the haloperidol dosage immediately if clinically feasible 2
• Switch to olanzapine starting at 2.5 mg per day at bedtime, which demonstrates significant reduction in Simpson-Angus Scale and Barnes Akathisia Scale scores 2
• Alternative atypical options include quetiapine (starting 25-50 mg twice daily, target 150-300 mg daily) or clozapine (though clozapine requires blood monitoring for agranulocytosis) 1, 3

For patients on risperidone 1:

• Reduce dose below 2 mg/day, as EPS risk increases significantly above this threshold, especially in elderly/dementia patients 1
• In first-episode psychosis, maintain maximum 4-6 mg haloperidol equivalent 1

Why Avoid Routine Anticholinergic Use

Guidelines specifically advise against routine anticholinergic use (benztropine, trihexyphenidyl) for preventing or treating EPS when dose reduction or switching is possible. 1, 2

The rationale includes 2:

• Anticholinergics worsen cognitive function, particularly problematic in elderly patients or those on cholinesterase inhibitors 2, 3
• They carry significant side effects including delirium, drowsiness, and paradoxical agitation 1
• They can paradoxically exacerbate agitation in patients with anticholinergic or sympathomimetic drug ingestions 4, 2
• Long-term haloperidol use carries up to 50% risk of irreversible tardive dyskinesia in elderly patients after 2 years 2

Secondary Management: Anticholinergic Treatment (When Necessary)

Acute Dystonia: Emergency Treatment

For severe or life-threatening acute dystonia, administer parenteral anticholinergic medication immediately. 1, 2

Specific dosing 1, 5:

• Benztropine 1-2 mg IM/IV provides rapid relief, with improvement sometimes noticeable within minutes 1, 5
• Diphenhydramine 12.5-25 mg IM/IV as alternative 1
• After acute treatment, continue benztropine tablets 1-2 mg twice daily to prevent recurrence 5

Drug-Induced Parkinsonism

If dose reduction is not feasible 1, 5:

• Benztropine 1-4 mg once or twice daily (oral or parenteral), individualized to patient response 5
• Usual daily dose ranges 1-2 mg, with maximum 6 mg 5
• Trihexyphenidyl 5-15 mg daily in divided doses (typically 3 doses at mealtimes) 6

Akathisia

Anticholinergics are less consistently effective for akathisia than for dystonia or parkinsonism 1, 7:

• Consider beta-blockers (propranolol, metoprolol) as more effective first-line agents 7
• Benzodiazepines may provide relief 7
• Reserve anticholinergics for cases where other options fail 1

Duration and Discontinuation of Anticholinergic Therapy

When anticholinergics are used, maintain them even after antipsychotic discontinuation to prevent delayed symptom emergence, but reassess need regularly. 1

Specific guidance 1, 5:

• After 1-2 weeks of treatment for transient EPS appearing early in neuroleptic therapy, withdraw anticholinergic to determine continued need 5
• Many patients no longer require anticholinergics during long-term therapy after the acute phase resolves 1
• If EPS recurs after withdrawal, reinstitute anticholinergic treatment 5
• Slowly developing drug-induced extrapyramidal disorders may not respond to benztropine 5

Prophylactic Anticholinergic Use: Limited Indications

Prophylactic anticholinergics should be reserved only for truly high-risk patients, not used routinely. 1

Consider prophylaxis only in 1:

• Young males (highest risk for acute dystonia) 1
• Patients with history of dystonic reactions 1
• Paranoid patients where compliance is an issue 1

Special Populations and Precautions

Elderly Patients

• Exercise extreme caution with anticholinergics due to oversedation, confusion, and paradoxical agitation 1
• Start quetiapine at low doses (25-50 mg twice daily) if switching from typical antipsychotic 3
• EPS risk with risperidone increases significantly above 2 mg/day; start at 0.25 mg/day at bedtime 1

Patients with Contraindications to Anticholinergics

Avoid diphenhydramine in 1:

• Glaucoma 1
• Benign prostatic hypertrophy 1
• Ischemic heart disease 1
• Hypertension 1

Patients on Anticholinergic or Sympathomimetic Drugs

Do not use anticholinergics or antipsychotics in patients with anticholinergic or sympathomimetic drug ingestions, as they can exacerbate agitation. 4, 2

Monitoring Requirements

When managing EPS 1, 3:

• Regular monitoring for early EPS signs is the preferred prevention strategy over prophylactic anticholinergics 1
• Monitor QTc interval on ECG, as most antipsychotics cause some QT prolongation 3
• Monitor cognitive function, particularly when using anticholinergics or in patients on cholinesterase inhibitors 3
• Reassess anticholinergic need after acute phase or if antipsychotic doses are lowered 1

Algorithm Summary

1. Identify EPS type (dystonia, parkinsonism, akathisia, tardive dyskinesia) 1
2. For acute dystonia: Administer benztropine 1-2 mg IM/IV or diphenhydramine 12.5-25 mg IM/IV immediately 1
3. For all other EPS: Reduce antipsychotic dose first 1, 2
4. If dose reduction insufficient: Switch to atypical antipsychotic (olanzapine 2.5 mg daily, quetiapine 25-50 mg twice daily, or clozapine) 1, 2, 3
5. Only if switching/reduction fails: Add anticholinergic (benztropine 1-4 mg daily or trihexyphenidyl 5-15 mg daily) 1, 5, 6
6. For akathisia specifically: Consider beta-blockers before anticholinergics 7
7. Reassess anticholinergic need after 1-2 weeks and periodically thereafter 1, 5