CB1 receptor antagonists could provide a targeted treatment for cannabis overdose, similar to naloxone for opioids | Research

The takeaway

A review proposes CB1 receptor antagonists as a molecular approach to treating acute cannabis overdose, analogous to how naloxone reverses opioid overdose, noting that many overdose symptoms are CB1-mediated.

Emergency medicine physicians, toxicologists, and pharmaceutical companies with CB1 antagonist compounds.

No specific cannabis antidote exists; CB1 antagonists could fill this gap

What the researchers found

Cannabis legalization has dramatically increased ED visits and hospitalizations for acute cannabis overdose, with edibles and synthetic cannabinoids responsible for disproportionate share. Many overdose symptoms (lethargy, ataxia, psychomotor impairment, panic, psychosis) are mediated through CB1 receptors. CB1 antagonists, originally developed for obesity and other conditions, could provide targeted reversal. Treatment is currently only supportive.

Why it matters

There is currently no specific antidote for cannabis intoxication. As cannabis overdose presentations increase (especially from edibles and synthetic cannabinoids), having a targeted reversal agent like the "naloxone of cannabis" could transform emergency management.

The numbers in context

Dramatic increase in cannabis-related ED visits; edibles and synthetic cannabinoids disproportionately responsible; current treatment is supportive only; CB1 antagonists previously developed for other indications.

How the study worked

Narrative review of evidence for CB1 receptor-mediated cannabis overdose symptoms and the potential of CB1 antagonists as treatment, drawing on pharmacology of rimonabant and related compounds.

What this study cannot tell us

Review article (no new clinical data); CB1 antagonists have not been tested for cannabis overdose in clinical trials; rimonabant withdrawal for psychiatric side effects raises safety questions even for acute use; dose and timing of administration unclear.

How to read the evidence

Moderate: well-reasoned pharmacological rationale with substantial supporting evidence, but no direct clinical trials.

When this study was published

Published 2020.

The bigger picture

Rimonabant (a CB1 antagonist) was withdrawn from the obesity market due to psychiatric side effects with chronic use. However, single-dose emergency use for acute cannabis overdose would avoid chronic side effects, potentially repurposing a failed drug for an unmet need.

Questions still open

Would a single dose of a CB1 antagonist be safe in acutely intoxicated patients? Could this work for synthetic cannabinoid overdoses, which may involve other receptors?

Common questions

Is there an antidote for cannabis overdose?

Not yet. Treatment is currently supportive (monitoring, reassurance). This review proposes that CB1 receptor antagonists could serve as a targeted reversal agent, similar to how naloxone reverses opioid overdose.

Why do people overdose on cannabis?

Edibles (delayed onset leads to overconsumption) and synthetic cannabinoids (much more potent than natural cannabis) are responsible for a disproportionate share of cannabis overdose ED visits. Symptoms range from extreme sedation to panic, psychosis, and hallucinations.

Read the original research

Cannabinoid1 (CB-1) receptor antagonists: a molecular approach to treating acute cannabinoid overdose.

Journal of neural transmission (Vienna, Austria : 1996), 127(2), 279-286

View on PubMed ↗Publisher’s paper ↗

Citation

Skolnick, Phil; Crystal, Roger. (2020). Cannabinoid1 (CB-1) receptor antagonists: a molecular approach to treating acute cannabinoid overdose.. Journal of neural transmission (Vienna, Austria : 1996), 127(2), 279-286. https://doi.org/10.1007/s00702-019-02132-7