Always check the BNF or equivalent for up-to-date prescribing advice.
Extrapyramidal side effects (EPS) occur with drugs that cause central dopamine blockade, particularly in the basal ganglia.
Older “typical” antipsychotics (e.g. haloperidol) are more likely to cause EPS than newer “atypical” agents.
Women and older adults are more susceptible - possibly due to reduced dopaminergic reserve and altered drug metabolism.
EPS can be profoundly distressing and may increase risk of depression, suicidality, anxiety, and substance misuse.

💊 Common Causes

Typical antipsychotics: Chlorpromazine, Haloperidol.
Atypical antipsychotics: Risperidone, Olanzapine (less common, dose-related).
Antiemetics: Metoclopramide, Prochlorperazine.
Any drug causing significant D2 receptor blockade in the nigrostriatal pathway.

⚙️ Aetiology & Pathophysiology

EPS result from D2 receptor blockade in the nigrostriatal pathway - disrupting the fine balance between dopaminergic and cholinergic activity.
Dopamine normally inhibits acetylcholine; blocking D2 receptors therefore produces a relative cholinergic excess → abnormal motor output.
The basal ganglia circuits involved mirror those affected in idiopathic Parkinson’s disease, hence the clinical similarity.

🩺 Clinical Syndromes

Acute Dystonia: Involuntary sustained muscle contractions (often torticollis, oculogyric crisis). Occurs hours to days after exposure; more common in young men.
Akathisia: A subjective sense of inner restlessness; patients may pace or rock. Can appear within days to weeks. Often misinterpreted as agitation or anxiety.
Drug-Induced Parkinsonism: Rigidity, bradykinesia, tremor, postural instability. Typically bilateral and symmetric, unlike idiopathic Parkinson’s disease. May include “rabbit syndrome” (perioral tremor).
Tardive Dyskinesia: Late-onset, often irreversible repetitive movements (lip-smacking, tongue protrusion, grimacing). Results from chronic dopamine receptor upregulation and supersensitivity.

🧩 Management Principles

🎯 Identify and stop or switch the offending drug (e.g. to quetiapine or clozapine if psychiatric stability allows).
⚕️ Acute dystonia: Treat with IM/IV Benztropine or Procyclidine. Symptoms usually resolve within minutes.
💤 Akathisia: Dose reduction, or add a benzodiazepine (e.g. lorazepam) or propranolol (non-selective β-blocker).
🦵 Drug-induced Parkinsonism: Consider anticholinergics (procyclidine) or amantadine; avoid levodopa as it may worsen psychosis.
😣 Tardive dyskinesia: Gradually withdraw the drug if feasible; switch to an atypical agent. VMAT-2 inhibitors (e.g. valbenazine, tetrabenazine) may be considered under specialist supervision.
❗ Avoid abrupt discontinuation - psychiatric relapse risk is high. Always taper under specialist review.

📚 References

NICE NG222: Medicines associated with movement disorders (2023)
BNF – Extrapyramidal Side Effects section
Katzung BG. Basic & Clinical Pharmacology, 15th ed. – Chapter on Antipsychotic Agents
British Journal of Psychiatry, 2022; 221(5): Motor Adverse Effects of Antipsychotics.

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Extrapyramidal symptoms

🧠 About

💊 Common Causes

⚙️ Aetiology & Pathophysiology

🩺 Clinical Syndromes

🧩 Management Principles

📚 References

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