Researchers found a potential antidote for synthetic cannabinoid overdose that works without triggering withdrawal | Research

The takeaway

A CB1 receptor negative allosteric modulator called PSNCBAM1 reversed the effects of the synthetic cannabinoid JWH018 both in lab neurons and in mice, including when given after exposure, without triggering withdrawal in chronically treated animals.

Emergency medicine researchers developing cannabinoid toxicity treatments; pharmacologists studying allosteric modulation of cannabinoid receptors.

First potential antidote for synthetic cannabinoid overdose identified

What the researchers found

Three CB1 NAMs (ABD1085, RTICBM189, PSNCBAM1) blocked JWH018 effects in cultured neurons. In vivo, only RTICBM189 and PSNCBAM1 blocked JWH018 when given beforehand. PSNCBAM1 was the most potent and also reversed JWH018 effects when given after exposure, mimicking an overdose scenario. Critically, PSNCBAM1 did not trigger withdrawal in chronically JWH018-treated mice.

Why it matters

Unlike opioid overdoses, which can be reversed with naloxone, there is currently no antidote for synthetic cannabinoid toxicity. This study identifies a pharmacological approach that works mechanistically differently from competitive antagonists, potentially offering the first tool for emergency treatment.

The numbers in context

Three NAMs tested. In vitro potency did not predict in vivo potency. PSNCBAM1 reversed JWH018 effects post-exposure (mimicking overdose). No withdrawal triggered after chronic JWH018 treatment with PSNCBAM1.

How the study worked

In vitro testing in autaptic hippocampal neurons expressing endogenous CB1-dependent circuits. In vivo nociception tests in mice with prophylactic and post-exposure dosing. Withdrawal assessment after chronic JWH018 treatment.

What this study cannot tell us

Preclinical study only. Single synthetic cannabinoid tested (JWH018); newer synthetics may behave differently. Mouse models may not predict human pharmacology. No human safety data for any CB1 NAM. In vitro potency did not predict in vivo effectiveness, complicating drug development.

How to read the evidence

Preclinical proof-of-concept with both in vitro and in vivo validation. No human data yet.

When this study was published

2024 study

The bigger picture

Synthetic cannabinoid emergencies account for thousands of ER visits annually. A reliable antidote could save lives, especially since synthetic cannabinoids are so potent that competitive antagonists may not be able to displace them from receptors quickly enough.

Questions still open

Would PSNCBAM1 work against the full range of current synthetic cannabinoids? What is the time window for effective post-exposure administration?

Common questions

What is a negative allosteric modulator?

A compound that binds to a receptor at a different site than the drug itself, reducing the receptor's response. Unlike a competitive blocker, it does not need to physically displace the drug from the receptor, making it potentially effective even against very potent synthetic cannabinoids.

Why is this needed if cannabis is relatively safe?

Synthetic cannabinoids are far more potent and dangerous than plant cannabis. They can cause seizures, cardiovascular emergencies, psychosis, and death. Emergency rooms currently have no specific antidote and must rely on supportive care.

Read the original research

CB1 Receptor Negative Allosteric Modulators as a Potential Tool to Reverse Cannabinoid Toxicity.

Molecules (Basel, Switzerland), 29(8)

View on PubMed ↗Publisher’s paper ↗

Citation

Flavin, Audrey; Azizi, Paniz; Murataeva, Natalia; Yust, Kyle; Du, Wenwen; Ross, Ruth; Greig, Iain; Nguyen, Thuy; Zhang, Yanan; Mackie, Ken; Straiker, Alex. (2024). CB1 Receptor Negative Allosteric Modulators as a Potential Tool to Reverse Cannabinoid Toxicity.. Molecules (Basel, Switzerland), 29(8). https://doi.org/10.3390/molecules29081881