Cannabinoid (Marijuana) Toxicity
Substance Use, Toxicology
First 5 Minutes
- Cannabinoid toxicity is a clinical diagnosis.
- Concomitant use of other substances (i.e., cocaine) will alter the presentation and should be considered.
- Phytocannabinoid (plant-derived) toxicity is rarely life-threatening, with treatment primarily focused on supportive care and observation.
- Synthetic cannabinoid toxicity may present with more severe symptoms (seizures, tachycardia, agitation) and potentially requires pharmacologic therapy.
Context
- Cannabinoids are agonists of the cannabinoid receptor, which are located throughout the body, especially in the CNS. Types of cannabinoids include phytocannabinoids (derived from the Cannabis plant, colloquially known as marijuana) and synthetic cannabinoids (lab produced and then often applied to dried plant products).
- The presentation of acute cannabinoid toxicity is dependent on the route of administration (inhalation vs ingestion), cannabinoid type (phyto vs synthetic), does, experience and vulnerability of the user, and the age of the user (pediatric vs adult).
- Synthetic cannabinoid is becoming increasingly available and is associated with greater morbidity and mortality due to increased potency on receptors and a sympathomimetic effect. Common street names include K2, K9, Aroma, Scooby Snax, Spice, Black Widow, and Black Mamba.
- Toxicity typically occurs with overuse, abuse, or inadvertent ingestion. Accidental overuse is more common with edible cannabis products, due to incorrect dosing of the product and variable time of onset of action.
- Treatment is typically unnecessary and supportive care may be offered to those experiencing significant discomfort. An exception is those presenting with more severe symptoms associated with synthetic cannabinoid toxicity.
Diagnostic Process
- The diagnosis of cannabinoid toxicity is clinical.
- In adult patients, workup for co-ingestions or differential diagnoses may be indicated based on presentation.
- In pediatric patients or accidental exposures, a urine drug screen via immunoassay to measure THC (the primary psychoactive compound in cannabis) may be necessary to aid in the diagnosis of toxicity.
- Synthetic cannabinoids are not detected on standard hospital urine drug screens due to their varying chemical structures.
- Clinical manifestations of cannabinoid use include:
- In addition to the above effects, clinical manifestations of acute toxicity include:
Recommended Treatment
- Most do not require treatment, but supportive therapy and observation may be offered to those experiencing significant discomfort.
- Decontamination is not recommended as the risks outweigh the benefits.
- Synthetic cannabinoid toxicity may require more aggressive intervention depending on symptom presentation:
- Patients should be observed for six hours until cessation of symptoms. Symptoms may last longer in patients who ingested cannabis products or those who used synthetic cannabinoids.
Criteria For Hospital Admission
- Admission is typically not required.
- Exceptions when admission is required include:
- Central nervous system depression.
- Altered mental status.
- Multiple seizures.
- Persistently abnormal vital signs.
Criteria For Transfer To Another Facility
- Transfer as needed if the patient’s clinical presentation requires a higher level of care than can be provided.
Criteria For Close Observation And/or Consult
- Patients who have returned to baseline do not require further testing/treatment.
Criteria For Safe Discharge Home
- Once the patient is minimally symptomatic or asymptomatic, has stable vital signs and has a method to safely get home, they are suitable for discharge.
Quality Of Evidence?
High
We are highly confident that the true effect lies close to that of the estimate of the effect. There is a wide range of studies included in the analyses with no major limitations, there is little variation between studies, and the summary estimate has a narrow confidence interval.
Moderate
We consider that the true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different. There are only a few studies and some have limitations but not major flaws, there are some variations between studies, or the confidence interval of the summary estimate is wide.
Low
When the true effect may be substantially different from the estimate of the effect. The studies have major flaws, there is important variations between studies, of the confidence interval of the summary estimate is very wide.
Justification
The quality of evidence is high, as this approach to cannabinoid toxicity is consistent across multiple medical textbooks and resources.
Related Information
OTHER RELEVANT INFORMATION
These links can be provided to patients:
https://www.canada.ca/en/health-canada/services/drugs-medication/cannabis.html
https://www2.gov.bc.ca/gov/content/safety/public-safety/cannabis/health-info
HealthLink BC Information Page:
https://www.healthlinkbc.ca/cannabis-and-your-health
Information on different types of cannabinoids:
https://www.nccih.nih.gov/health/cannabis-marijuana-and-cannabinoids-what-you-need-to-know
Reference List
Kelly BF, Nappe TM. Cannabinoid toxicity [Internet]. StatPearls – NCBI Bookshelf. 2023. Available from: https://www.ncbi.nlm.nih.gov/books/NBK482175/#:~:text=Cannabis%20toxicity%20in%20children%20can,seizures%20and%20sedation%20can%20occur
Nelson LS, Goldfrank LR. Cannabinoids. In: Goldfrank’s toxicologic emergencies. 11th ed. New York Mcgraw-Hill Education; 2019.
O’Malley GF, O’Malley R. Marijuana (Cannabis) [Internet]. MSD Manual Professional Edition. 2024. Available from: https://www.msdmanuals.com/professional/special-subjects/illicit-drugs-and-intoxicants/marijuana-cannabis#top
RESOURCE AUTHOR(S)
DISCLAIMER
The purpose of this document is to provide health care professionals with key facts and recommendations for the diagnosis and treatment of patients in the emergency department. This summary was produced by Emergency Care BC (formerly the BC Emergency Medicine Network) and uses the best available knowledge at the time of publication. However, healthcare professionals should continue to use their own judgment and take into consideration context, resources and other relevant factors. Emergency Care BC is not liable for any damages, claims, liabilities, costs or obligations arising from the use of this document including loss or damages arising from any claims made by a third party. Emergency Care BC also assumes no responsibility or liability for changes made to this document without its consent.
Last Updated Mar 15, 2024
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