Extra Pyramidal Side Effects (EPSE)

Extra Pyramidal Side Effects (EPSE)

These are side effects from dopamine antagonists, commonly typical antipsychotics

• Acute dystonia

• Akathisia

• Parkinsonism

• Tardive dyskinesia

• Neuroleptic malignant syndrome

Acute Dystonia

• Recent dopamine antagonist, e.g. metoclopramide

• Acute fixed flexion of muscle, e.g. neck or eye muscles

• Systemically well

• Management: 

  1. Procyclidine

  2. Diphenhydramine (H1 antagonist)

Akathisia

• Restless legs

• Associated with typical antipsychotics

• Likely separate syndrome from Restless Leg Syndrome 

• Management

  1. Change antipsychotic

  2. Benztropine, betablockers (propanolol), benzodiazepine, mirtazapine (BBBM)

Parkinsonism

• Associated with long term antipsychotic use

• Slow of movements, similar to Parkinson's: resting tremor, bradykinesia

• Differentiating feature in Parkinsonism is that the tremor is bilateral but unilateral in Parkinson's

Tardive Dyskinesia

• Associated with antipsychotic use for 20+ years

• Small repetitive movements

Neuroleptic malignant syndrome (NMS)

• Acute medical emergency 

• Caused by dopamine blockade

• Presentation: febrile, wooden rigidity

• Differential: serotonin syndrome has hyper-reflexivity (unlike NMS)

References and Resources

Written in 2025