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Drug-induced Extrapyramidal Symptoms

Drug-induced extrapyramidal symptoms (EPS) are abnormal movements or restlessness caused by medicines that disrupt dopamine signalling.

Key takeaways

  • Acute dystonia causes painful twisting or eye deviation, akathisia causes inner restlessness, and parkinsonism causes slowness, stiffness or tremor.
  • Tardive dyskinesia develops later and requires a different strategy from acute EPS; anticholinergic treatment may worsen it.
  • The suspected medicine should be reviewed promptly, but abrupt stopping can destabilise the condition it was treating.

The listings below do not identify the EPS subtype; prescriber assessment should guide dose change, switching or symptom treatment.

Recognising timing and pattern

Acute dystonia often appears within days, akathisia over days to weeks and parkinsonism over weeks to months. Tardive movements commonly involve repetitive mouth, tongue or limb activity after longer exposure. Antiemetics as well as antipsychotics can cause EPS.

Management decisions

Airway-threatening dystonia needs immediate anticholinergic treatment. Akathisia may improve with dose adjustment or a beta blocker, while parkinsonism may require switching and selected symptom treatment. Tardive dyskinesia uses structured severity assessment and may respond to VMAT2 inhibitors.

When to seek urgent care

Seek emergency care for neck or throat spasm, breathing or swallowing difficulty, severe rigidity with fever and confusion, collapse, or uncontrollable agitation with immediate self-harm risk.