Cannabis intoxication may be stopped with anti-obesity drug

Researchers from the Queen Mary University of London in the United Kingdom may have found an antidote to cannabinoid intoxication. Findings may counter the potentially life-threatening effects of intoxication with synthetic cannabinoids.

More and more people are turning to synthetic cannabinoids, or "legal highs," as an alternative to marijuana.

These substances go by the names of synthetic marijuana, spice, K2, black mamba, or crazy clown.

In the United States, these drugs seem to be particularly popular among young males.

Synthetic cannabinoids are marketed and perceived as a safer and less harmful alternative to cannabis. However, as the National Institute on Drug Abuse (NIDA) warn, these psychoactive substances may be considerably stronger than cannabis.

In fact, the NIDA caution, the side effects of synthetic cannabinoids are often "unpredictable and, in some cases, severe or even life-threatening."

The use of synthetic marijuana has been linked to seizures and psychosis, among other side effects.

Additionally, it has been reported that the number of deaths related to the use of synthetic cannabinoids has tripled in recent years, and the Centers for Disease Control and Prevention (CDC) have referred to the substances as an "emerging public health threat."

In the new study - published in the British Journal of Pharmacology - researchers have investigated possible avenues for attenuating the effects of intoxication with cannabis and synthetic cannabinoids.

The study was carried out by Gareth Pryce and David Baker, both from the Blizard Institute at Queen Mary University of London.

As the researchers explain, cannabis intoxication, or the feeling of "being high," occurs when the so-called CB1 brain receptors are activated.

Synthetic cannabinoids act on the same receptor, but intoxication with these substances may have more dire effects than marijuana.

CB1 receptor antagonists block intoxication

The researchers started from the hypothesis that "CB1 receptor antagonists could act as antidotes to cannabinoid intoxication."

So, they designed a mouse model in which they tested the effect of a molecule called AM251 - which is a CB1 receptor antagonist - against cannabinoid intoxication.

They administered the rodents a dose of a CB1 receptor agonist, or a cannabinoid drug, in order to induce cannabis intoxication-like effects, such as sedation, hypothermia, and hypomotility.

Twenty minutes after receiving these cannabinoids and exhibiting signs of intoxication, the mice received a dose of 5 milligrams per kilogram of the AM251 molecule.

Administering the AM251 molecule blocked the cannabinoid's effects in mice, visibly and quickly reducing behavioral signs of intoxication, including sedation and hypothermia.

In fact, sedation was significantly reduced 20 minutes after administration, and hypothermia 40 minutes following administration of the AM251 molecule.

The authors conclude:

"Cannabinoid receptor antagonists have been widely used and so may provide an acceptable single-dose antidote to cannabinoid intoxication. This use may save human life, where the life-threatening effects are mediated by cannabinoid receptors."

Anti-obesity drug may act as antidote

Given the findings, the researchers say that the slimming drug called rimonabant may serve as an antidote for intoxication with cannabis and synthetic cannabinoids.

Rimonabant was initially designed to treat obesity. It is a "selective CB1 endocannabinoid receptor antagonist" whose use and "commercial development," as the authors explain, has been ceased due to its adverse neuropsychiatric effects.

However, the researchers suggest that it may be worth re-manufacturing the drug in order to "block potentially life-threatening, cannabinoid intoxication."

The researchers concede that "cannabis intoxication is not usually fatal in humans," and that "there is not enough data to be confident that the toxicity of the 'Spice' products is really due to their cannabinoid content."

In this sense, further studies and trials are needed, the researchers note.