Liverpool Hospital Emergency Department


  • Acute dystonic reaction – extrapyramidal: this is generally a side effect of  medications received – e.g. antipsychotics, metoclopramide (usually within hrs or up  to 5 days of starting) 


  • Injectable 1mg/ml – (2ml ampoule)
  • Tablet form – 2mg PO 

Dosage and Administration 


  • Adult – 1-2mg IV – slow IV injection – if no IV IM (takes longer).
  • Paediatric – 0.02mg/kg to max 1mg IV.
  • Usually responds within 5-20mins – if persists can give second dose.  


  • 2mg bd as necessary (given to take home if symptoms return) 

Side Effects 

Anticholinergic side effects  

  • Dry mouth
  • blurred vision
  • Tachycardia
  • delirium
  • urinary retention 

Pit Falls 

  • Remember good supportive care for acute dystonic reaction
  • May need airway support
  • May need benzos – e.g. midazolam 1-2mg IV/IM
  • If no benztropine – Can try promethazine 

Caution if on other meds with anticholinergic effects