Acute Drug-Induced Extrapyramidal Syndrome (EPS)
Acute drug-induced extrapyramidal syndrome (EPS) comprises movement disorders caused mainly by dopamine-blocking medicines, especially antipsychotics and antiemetics such as metoclopramide. Acute dystonia may threaten the airway and is a psychiatric and medical emergency.
Red flag: stridor, choking, difficulty speaking or swallowing, tongue protrusion, cyanosis, fever with rigidity, reduced consciousness or autonomic instability requires immediate ABC support, stopping the suspected medicine and urgent medical review.
Mechanism and risk factors
Dopamine D2 blockade in the nigrostriatal pathway creates relative cholinergic excess, disturbing normal movement. Risk increases with high-potency first-generation antipsychotics, rapid dose escalation, IM dosing, young age, male sex, previous dystonia, dehydration, substance use and simultaneous dopamine-blocking drugs.
Types and recognition
| Syndrome | Onset and manifestations | Key distinction |
|---|---|---|
| Acute dystonia | Hours–days: painful neck twisting, jaw spasm, upward eye deviation, tongue protrusion, back arching; laryngeal spasm may obstruct the airway. | Sudden sustained muscle contraction. |
| Akathisia | Days–weeks: inner restlessness, pacing, rocking, inability to sit; may be mistaken for worsening agitation. | Subjective urge to move. |
| Drug-induced parkinsonism | Days–weeks: rigidity, tremor, slow movement, masked face, shuffling gait, drooling. | Symmetric parkinsonian features. |
| Tardive dyskinesia | Months–years: repetitive mouth, tongue, face, trunk or limb movements. | Late syndrome; may persist. |
| Neuroleptic malignant syndrome (NMS) | Fever, generalized “lead-pipe” rigidity, altered consciousness, tachycardia/labile BP, sweating and raised CK. | Life-threatening systemic emergency, not ordinary EPS. |
Assessment
- ABCDE, temperature, SpOâ‚‚, pulse, BP, consciousness and glucose.
- Record every prescribed, injected, over-the-counter and herbal medicine, dose, route, timing and recent change.
- Describe movements precisely; ask about painful spasm, swallowing, breathing and inner restlessness.
- Exclude seizures, tetanus, meningitis, hypocalcaemia, stroke, Parkinson disease, intoxication, catatonia and anxiety.
- For suspected NMS obtain CK, renal function, electrolytes, urinalysis/myoglobin, FBC, LFTs and ECG; monitor urine output.
Emergency management
- Stop the suspected causative drug and notify the prescriber. Do not administer the next dose until reviewed.
- Airway first: oxygen, suction and resuscitation equipment; urgent anaesthetic/medical help for laryngeal dystonia.
- Acute dystonia: give the facility-approved parenteral anticholinergic or antihistamine prescribed by an authorized clinician (commonly benztropine, biperiden or promethazine according to local formulary). Improvement usually begins rapidly; observe for recurrence and prescribe only a short oral course when ordered.
- Akathisia: reduce dose or switch medicine; consider a prescribed beta-blocker or short-term benzodiazepine after checking contraindications. Assess suicide risk because severe akathisia is intensely distressing.
- Parkinsonism: dose reduction/switch; short-term anticholinergic may be used when benefits outweigh cognitive, urinary, visual and gastrointestinal harms.
- Tardive dyskinesia: specialist review, structured severity assessment and change to a lower-risk regimen; do not automatically add anticholinergic because it may worsen tardive movements.
- NMS: stop dopamine blockers, transfer urgently, cool, hydrate, monitor cardiorespiratory/renal status and treat complications in high-dependency care.
Medicines: nursing pharmacology
| Medicine/group | Indication/action | Contraindications/interactions | Adverse effects and monitoring |
|---|---|---|---|
| Parenteral anticholinergic (benztropine/biperiden) | Rapid reversal of acute dystonia by restoring dopamine–acetylcholine balance. Dose follows local protocol. | Caution glaucoma, urinary retention, ileus, prostatic obstruction; additive effects with other anticholinergics. | Dry mouth, blurred vision, tachycardia, constipation, confusion; reassess airway and spasm frequently. |
| Promethazine | Antihistamine with anticholinergic action; alternative for dystonia where protocol permits. | Caution respiratory depression, severe CNS depression; additive sedation with alcohol/opioids/benzodiazepines. | Sedation, hypotension and anticholinergic effects; monitor BP, respiration and injection site. |
| Propranolol | Often used for akathisia after assessment. | Avoid/caution asthma, bradycardia, hypotension, heart block; interacts with other rate-lowering drugs. | Bradycardia, hypotension, bronchospasm; check pulse/BP. |
Important: WHO advises against routine long-term prophylactic anticholinergics. Use the lowest effective antipsychotic dose, one antipsychotic at a time where possible, and short-term EPS treatment with regular review.
Nursing care plan
| Diagnosis | Interventions with rationale |
|---|---|
| Ineffective airway clearance | Assess voice, stridor, swallowing, RR and SpOâ‚‚; keep oxygen/suction/resuscitation equipment ready; escalate immediately. |
| Acute pain/anxiety | Explain that the reaction is medicine-induced and treatable; remain with the patient; reduce stimulation; support affected body parts without force. |
| Impaired mobility/risk for falls | Assist walking and self-care, maintain clear environment, institute falls precautions and reassess after treatment. |
| Deficient knowledge | Teach early symptoms, causative medicine, when to return, and not to stop or restart psychiatric medicines without review. |
Documentation, prevention and follow-up
- Record onset, movement pattern, medicine exposure, airway findings, treatment, response and adverse effects; report as an adverse drug reaction.
- Place the reaction prominently in notes and medicine chart; give patient-held information where available.
- At every antipsychotic review assess movement, adherence, mental state, metabolic effects and need for the current dose.
Revision questions
- Differentiate dystonia, akathisia, parkinsonism, tardive dyskinesia and NMS.
- Why can acute dystonia become fatal?
- Outline nursing management during the first 15 minutes.
References
- WHO. mhGAP Guideline, 2023 and mhGAP Intervention Guide.
- Uganda Ministry of Health. Uganda Clinical Guidelines, 2023.
- Clinical practice guidance on emergencies associated with psychotropic medicines.