What is the treatment for a risperidone (antipsychotic medication) overdose?

Treatment of Risperidone Overdose

The management of risperidone overdose requires immediate supportive care including close medical supervision, ensuring adequate airway, oxygenation, and ventilation, monitoring cardiac rhythm and vital signs, and providing symptomatic treatment, as there is no specific antidote for risperidone overdose. 1

Clinical Presentation of Risperidone Overdose

• The most frequently reported signs and symptoms of risperidone overdose are exaggerations of the drug's known pharmacological effects: drowsiness, sedation, tachycardia, hypotension, and extrapyramidal symptoms 1
• Other adverse reactions reported with risperidone overdose include prolonged QT interval and convulsions 1
• Torsade de pointes has been reported in association with combined overdose of risperidone and paroxetine 1
• In children, even accidental ingestion of low doses can cause extrapyramidal symptoms including bilateral upward eye gaze, jerky movements of extremities, and motor restlessness 2

Initial Management

• Contact a certified poison control center (1-800-222-1222 or www.poison.org) for the most up-to-date management guidance 1
• Ensure adequate airway, oxygenation, and ventilation 1
• Monitor cardiac rhythm and vital signs closely 1, 3
• Consider the possibility of multiple drug overdose, as this can complicate the clinical presentation 1
• Perform gastrointestinal decontamination with activated charcoal with sorbitol if the patient presents within 1-2 hours of ingestion 2, 3

Pharmacological Management

• For extrapyramidal symptoms, which are common in risperidone overdose, administer diphenhydramine intravenously 2
• For severe agitation, benzodiazepines may be used, with lorazepam 1-2 mg IV/IM being an appropriate option 4
• In cases of significant cardiovascular effects:
  • Monitor ECG for QT prolongation 1, 5
  • Treat hypotension with IV fluids and, if necessary, vasopressors 3
• For seizures, administer anticonvulsants as needed 3

Monitoring and Follow-up

• Continuous cardiac monitoring is essential, particularly for QT prolongation and dysrhythmias 1, 5
• Monitor for extrapyramidal symptoms, which may persist and require repeated treatment 2
• Laboratory monitoring should include:
  • Complete blood count 4
  • Electrolytes (particularly for hyponatremia and hypokalemia) 1
  • Liver function tests 4
  • Toxicology screen to identify potential co-ingestants 3

Special Considerations

• Symptoms typically resolve within 24-72 hours in most patients 3
• Pediatric patients may be more susceptible to extrapyramidal symptoms even at relatively low doses 2
• Elderly patients may require lower doses of treatment medications and closer monitoring 4
• Patients with pre-existing cardiac conditions are at higher risk for complications 1, 5

Common Pitfalls to Avoid

• Failing to monitor for cardiac complications, especially QT prolongation which can lead to life-threatening arrhythmias 1, 5
• Overlooking potential co-ingestants that may interact with risperidone and complicate management 1, 3
• Inadequate treatment of extrapyramidal symptoms, which may require repeated doses of anticholinergic medication 2
• Discharging patients too early before all symptoms have resolved, as some effects may persist for up to 72 hours 3
• Underestimating the potential for serious complications in pediatric patients, even with relatively small ingestions 2