Extrapyramidal symptoms and tardive dyskinesia — Rapid

Synopsis

Distinguish acute dystonia, parkinsonism, akathisia and tardive dyskinesia by their timing and movement pattern, then select treatment that relieves the actual syndrome without worsening another motor adverse effect.

Acute dystonia usually follows recent exposure or dose escalation and causes sustained, often painful abnormal postures or an oculogyric crisis.
Drug-induced parkinsonism produces slowed movement, rigidity and tremor; review dopamine blockers before labelling a new degenerative disorder.
Akathisia combines an internal urge to move with observable restlessness and usually responds poorly to anticholinergics.
Tardive dyskinesia commonly causes repetitive tongue, lip, facial, limb or truncal movements after longer dopamine-blocker exposure.
Anticholinergics can help acute dystonia or parkinsonism but may aggravate tardive dyskinesia and should not be routine prophylaxis.
UK procyclidine injection has been discontinued; the 2026 SPS guidance describes imported, UK-unlicensed benztropine injection for acute dystonia.
Changes to the causative antipsychotic need a psychiatric relapse plan, especially when movements emerge during dose reduction.

Key red flags

Stridor, dysphagia, cyanosis or inability to handle secretions during a suspected dystonic reaction requires immediate resuscitation assessment.

Fever, generalised severe rigidity, confusion and unstable observations suggest neuroleptic malignant syndrome rather than uncomplicated parkinsonism.

Severe akathisia can produce intolerable distress and suicidal thinking; assess immediate safety as well as the movement disorder.

Investigation priorities

Full exposure timelineFirst step

Identify dopamine-blocking and anticholinergic changes that explain the movement.

Management branches

Acute rescueTreat a dystonic reaction promptly

Painful sustained posturing or eye deviation develops after a relevant medicine.

Assess airway and swallowing, summon urgent support for respiratory involvement and stop the precipitating medicine.
Administer the locally stocked parenteral anticholinergic using its own dosing instructions; benztropine is not milligram-equivalent to procyclidine.
Reassess response, observe for recurrence and agree short-term follow-up treatment and avoidance of the precipitant before discharge.

Key medicines

Benztropine injection for adult acute dystoniaGive 1–2 mg intramuscularly or intravenously; if there is no response a repeat may be given after 30 minutes intramuscularly or 10 minutes intravenously, within the authorised daily maximum.UK use is unlicensed; SPS reports daily maxima of 4–6 mg and gives a 4 mg/24-hour example. Specify route and maximum explicitly, consider cumulative anticholinergic exposure and do not assume dose equivalence.

Oral procyclidine for drug-induced parkinsonismStart 2.5 mg orally three times daily, then adjust cautiously to response; the cited tablet SmPC usually uses 10–20 mg daily in divided doses.Avoid routine prophylaxis and review continuing need; constipation, urinary retention, glaucoma risk, confusion and worsening tardive dyskinesia may outweigh benefit.

Open full textbook →Answer 2 questions