How should an acute cannabis overdose be managed in adults and children, including airway, breathing, circulation assessment and symptom‑directed therapy?

Management of Acute Cannabis Overdose

Acute cannabis overdose should be managed with symptom-directed supportive care, including airway protection if needed, benzodiazepines for severe anxiety or agitation, and IV fluids for dehydration, while avoiding opioids which worsen nausea and carry addiction risk. 1, 2

Initial Assessment: Airway, Breathing, Circulation

Airway and Breathing

• Assess for altered mental status, stupor, or obtundation that may compromise airway protection, particularly in children who are more susceptible to severe toxicity including seizures and coma 1
• Monitor for respiratory depression in severe cases, though this is uncommon with cannabis alone 1
• Evaluate oxygen saturation and provide supplemental oxygen if hypoxic 1

Circulation

• Screen for cardiovascular complications, as acute cannabis toxicity can cause myocardial ischemia or infarction, particularly in older adults 3
• Obtain baseline ECG if considering haloperidol or other QT-prolonging medications 4
• Assess for dehydration by evaluating skin turgor, mucous membrane moisture, capillary refill, and mental status 4

Neurological Status

• Children require heightened vigilance as they are more susceptible to seizures and coma from cannabis toxicity 1
• Assess for ataxia, psychomotor impairment, hallucinations, and psychotic symptoms 1, 5

Symptom-Directed Management

For Anxiety, Panic, and Agitation

• Administer benzodiazepines as first-line treatment for severe anxiety, panic attacks, or agitation 4, 1
• Provide reassurance and a calm, quiet environment for mild to moderate anxiety 2
• Avoid antipsychotics unless severe psychotic symptoms are present, as they carry risks of extrapyramidal effects and QT prolongation 4

For Nausea and Vomiting

• Distinguish between simple cannabis intoxication and cannabinoid hyperemesis syndrome (CHS), which occurs with chronic heavy use (>1 year, >4 times weekly) and presents with stereotypical episodic vomiting 4, 6
• Look for the pathognomonic feature of CHS: compulsive hot water bathing behavior for symptom relief, reported in 71% of cases 4, 6

For standard cannabis-induced nausea:

• Administer standard antiemetics such as ondansetron 16 mg IV/PO 4
• Provide IV fluids for dehydration 4

For suspected CHS:

• Haloperidol 5 mg IV is most effective, reducing hospital length of stay by nearly 50% 4
• Consider adding lorazepam 2 mg IV for anxiolysis and enhanced symptom control 4
• Topical capsaicin 0.1% cream applied to the abdomen may improve symptoms through activation of transient receptor potential vanilloid type 1 receptors 4
• Alternative antiemetics include promethazine 12.5-25 mg IV (central line only), olanzapine 2.5-5 mg PO, or droperidol 4
• Standard antiemetics are often ineffective in CHS 4, 6

For Seizures (Primarily in Children)

• Administer benzodiazepines (lorazepam 0.1 mg/kg IV or diazepam 0.2 mg/kg IV) as first-line treatment 1
• Provide additional supportive care and monitoring given children's increased susceptibility 1

Hydration Management

• Oral rehydration is first-line for mild to moderate dehydration 4
• IV fluids are necessary for severe dehydration or intractable vomiting 4

Critical Medications to Avoid

• Never administer opioids for cannabis overdose symptoms, as they worsen nausea and carry significant addiction risk, particularly in cannabis users 4, 3
• Avoid nonspecific antidiarrheal agents (loperamide, kaolin-pectin) which have limited evidence and may cause side effects 4

Special Considerations for Edibles and Synthetic Cannabinoids

• Edibles and synthetic cannabinoids cause disproportionately severe toxicity compared to smoked cannabis, with symptoms including extreme lethargy, severe psychomotor impairment, hallucinations, and psychosis 7
• Synthetic cannabinoids often possess higher potencies and efficacies than Δ9-THC, requiring more aggressive supportive care 7
• Symptom onset from edibles is delayed (1-3 hours) but prolonged compared to inhaled cannabis 7

Disposition and Follow-Up

• Most patients can be managed conservatively and discharged once symptoms resolve, typically within several hours 2
• Admit patients with severe symptoms (persistent altered mental status, cardiovascular complications, intractable vomiting, seizures) for observation 1
• For suspected CHS, counsel on cannabis cessation as the only definitive cure and consider referral to addiction medicine or psychiatry 4, 6
• Provide education that symptoms resolve with cannabis cessation, requiring 6+ months of abstinence for definitive resolution 4

Common Pitfalls

• Failing to recognize CHS in chronic cannabis users with cyclic vomiting, leading to extensive unnecessary workup 4, 6
• Administering opioids for abdominal pain or anxiety, which worsens outcomes 4
• Underestimating toxicity in children, who require more aggressive monitoring and supportive care 1
• Missing cardiovascular complications in older adults presenting with acute cannabis toxicity 3
• Patients may report cannabis helps their symptoms, leading to continued use and worsening of underlying CHS 4