Management overview for synthetic cannabinoid-receptor agonist poisoning

Synthetic cannabinoid-receptor agonists are designed to mimic the effects of tetrahydrocannabinol (THC), the active ingredient in cannabis. They are often termed ‘synthetic marijuana’ or ‘synthetic cannabis’. Hundreds of compounds are classified as synthetic cannabinoid-receptor agonists, and their potency and effects are less predictable than cannabis.

Cannabis is a partial agonist at cannabinoid receptors, whereas synthetic cannabinoid-receptor agonists are full agonists. In addition, cannabis contains cannabidiol, a compound that ameliorates some of the effects of THC, while synthetic cannabinoid-receptor agonists do not. Highly potent synthetic cannabinoid-receptor agonists can cause marked psychomotor agitation and seizures. Compared with cannabis use, anxiety, paranoia and psychotic symptoms are more common and severe with synthetic cannabinoid-receptor agonists.Synthetic cannabinoid-receptor agonists have a higher potential for addiction and withdrawal than cannabis.

Synthetic cannabinoid-receptor agonists are usually liquid formulations that are sprayed onto herbal mixtures, to be smoked. To disguise their intended use, they are often labelled as ‘potpourri’ or ‘incense’ with the disclaimer ‘not for human consumption’. The liquid formulations are also used in e-cigarettes and vaporisers. The preparations have many names, depending on the specific formulation, including ‘spice’, ‘K2’, ‘crazy monkey’ or ‘buddha blue’. These drugs are accessible over the internet and ‘darknet’¹.

Management of synthetic cannabinoid-receptor agonist poisoning is primarily supportive care, aiming to manage acute behavioural disturbance and prevent cardiovascular complications.