What is the treatment for a cannabis overdose in a patient with no prior medical history?

Treatment for Cannabis Overdose

There is no specific antidote for cannabis overdose—management is entirely supportive care focused on symptom control and monitoring for serious complications. 1, 2, 3

Immediate Assessment and Risk Stratification

Rule out life-threatening conditions first before attributing all symptoms to cannabis toxicity, including acute abdomen, bowel obstruction, mesenteric ischemia, pancreatitis, and myocardial infarction. 3 This is critical because cannabis symptoms can mimic serious pathology.

Vital Sign Monitoring

• Monitor heart rate, blood pressure, and respiratory rate continuously for tachycardia, arrhythmias, or signs of myocardial ischemia. 1, 2
• Cardiac monitoring is essential as cannabis can trigger cardiovascular events including myocardial infarction and stroke, especially in those with pre-existing cardiovascular disease. 1

Timing Considerations

• Edible cannabis has delayed onset (30 minutes to 2 hours) with peak effects at 2-4 hours, meaning symptoms may worsen significantly after initial presentation. 1, 2
• Symptoms from inhalation typically resolve within 2-4 hours as THC effects wear off. 2, 4

Supportive Care Algorithm

For Mild-Moderate Symptoms

• Provide reassurance that symptoms are self-limited and will resolve within hours. 2
• Place patient in a calm, quiet environment away from stimulation. 1, 2
• Avoid pharmacological intervention unless symptoms are severe or prolonged. 2

For Severe Agitation/Anxiety

• Benzodiazepines are first-line for severe panic symptoms not resolving with supportive measures alone. 2, 3
• Options include lorazepam (Ativan) or temazepam (Restoril). 2
• These address the stress-mediated component of toxicity through sedation and anxiolysis. 3

For Psychotic Symptoms

• Haloperidol or droperidol for severe cannabis-related psychotic symptoms and refractory agitation. 3
• Butyrophenones (haloperidol, droperidol) have shown some success in cannabinoid hyperemesis syndrome as well. 5

Critical Medications to AVOID

• Never use opioids for symptom management—they worsen nausea and carry high addiction risk. 2, 3
• Do not prescribe dexamphetamines—explicitly contraindicated for cannabis-related disorders. 2

Special Population Considerations

Older Adults (≥65 years)

• Face increased risk for sedation, obtundation, myocardial ischemia, falls from orthostatic hypotension, and ataxia. 1, 2
• Require heightened vigilance and more intensive monitoring. 1

Children

• More susceptible to cannabis toxicity, particularly seizures and coma. 4
• May require additional supportive care for these potential symptoms. 4

Patients with Pre-existing Conditions

• Cardiovascular disease, respiratory conditions, and mental health disorders require heightened vigilance. 1
• Cannabis worsens bipolar disorder and increases risk of manic/psychotic symptom exacerbation. 3

Follow-Up and Monitoring

Short-Term (1-2 weeks)

• Schedule primary care follow-up within 1-2 weeks to screen for development of cannabis use disorder symptoms (irritability, insomnia, headaches). 1, 2
• Screen for mental health sequelae including persistent anxiety, panic attacks, depression, and psychotic symptoms. 1, 2

Long-Term Monitoring

• Monitor for cannabis withdrawal symptoms if patient was a regular user—symptoms begin 24-72 hours after cessation, peak in first week, and last 1-2 weeks. 5, 2
• Withdrawal symptoms include irritability, anxiety, insomnia, decreased appetite, restlessness, altered mood, and physical symptoms (abdominal pain, tremors, sweating, fever, headache). 5
• Screen for cognitive impairment if exposure was prolonged. 1

Critical Pitfalls to Avoid

• Do not assume symptoms will be mild—edible cannabis products can lead to higher plasma concentrations and increased risk of emergency department visits. 1, 2
• Do not delay seeking care for cardiovascular symptoms—cannabis can precipitate myocardial ischemia in at-risk individuals. 1, 2
• Do not attribute all symptoms to cannabis without ruling out other serious pathology first. 3

Definitive Management

Cannabis cessation is the only definitive treatment and should be strongly recommended. 3 For cannabinoid hyperemesis syndrome specifically, complete symptom resolution requires 6+ months of abstinence for definitive confirmation. 3