What is the management of dextromethorphan (DM) poisoning?

Management of Dextromethorphan Poisoning

The management of dextromethorphan (DM) poisoning requires immediate contact with a Poison Control Center (1-800-222-1222) and supportive care focused on airway management, breathing support, and treatment of specific symptoms based on severity. 1

Initial Assessment and Triage

Severity Assessment

• Mild toxicity: Infrequent vomiting, mild somnolence (arousable with speaking voice or light touch)
• Moderate toxicity: Nystagmus, tachycardia, hypertension, ataxia
• Severe toxicity: Hallucinations, respiratory depression, seizures, coma, serotonin syndrome

Triage Recommendations

• Patients with ingestions >7.5 mg/kg should be referred to an emergency department 2
• Patients with ingestions of 5-7.5 mg/kg require poison center follow-up every 2 hours for up to 4 hours 2
• All patients with suicidal intent, intentional abuse, or suspected malicious intent require emergency department evaluation 2
• Asymptomatic patients more than 4 hours post-ingestion can be observed at home 2

Treatment Protocol

Supportive Care

• Airway management: Establish open airway; provide bag-mask ventilation if needed; intubation for severe respiratory depression 3
• Circulation: Monitor vital signs and treat hypotension or dysrhythmias according to standard protocols
• Seizure management: Administer intravenous benzodiazepines for seizures 2

Decontamination

• Do not induce emesis 2
• Activated charcoal: Consider single-dose activated charcoal for recent ingestions (within 1 hour) if no contraindications exist 2, 4
• Do not delay transportation to administer activated charcoal 2

Specific Treatments

• For respiratory depression: Consider naloxone in usual doses for opioid overdose, particularly if respiratory depression is present 2
• For serotonin syndrome:
  • Benzodiazepines for agitation and seizures
  • External cooling measures for hyperthermia (>104°F/40°C) 2
  • Discontinue all serotonergic agents

Special Considerations

• Patients on MAOIs or SSRIs: Higher risk for serotonin syndrome; requires poison center follow-up every 2 hours for 8 hours 2
• Extended-release formulations (dextromethorphan polistirex): Longer duration of toxicity, potentially requiring extended monitoring 5
• Intravenous lipid emulsion (ILE): May be considered in severe cases with serotonin syndrome not responding to conventional therapy 6

Monitoring

• Vital signs (blood pressure, heart rate, respiratory rate, temperature)
• Mental status
• Pupillary changes (mydriasis is common)
• Muscle rigidity or hyperreflexia (signs of serotonin syndrome)

Laboratory Evaluation

• Basic metabolic panel
• Consider toxicology screening if co-ingestion suspected
• Carefully assess for other drugs involved, particularly acetaminophen 2

Disposition

• Patients exhibiting more than mild symptoms require emergency department evaluation 2
• Patients with severe symptoms require ICU admission
• Discharge criteria: Resolution of symptoms, normal vital signs, and return to baseline mental status

Prevention

• Keep medications out of reach of children 1
• Patient education regarding proper dosing and potential for abuse

Remember that dextromethorphan poisoning can present with a wide range of symptoms from mild CNS depression to severe serotonin syndrome, and management should be tailored to symptom severity with early consultation with a Poison Control Center.