Synthetic Cannabinoids (Spice, K2)
The cannabinoid receptor agonists mimic the effects of THC and anandamide (the endogenous ligand for cannabinoid receptors in the central nervous system and other organs) by binding to the CB1 and CB2 receptors in the brain and nervous system.
Very little is currently known about the detailed pharmacology and toxicology of the active ingredients within synthetic cannabis products. Very few formal human studies have been published on only a proportion of the newly discovered synthetic cannabinoid-type chemicals.
Some of these cannabinoids may have considerably shorter or longer half-lives (duration of action) than the more recognised ones (such as THC) and/or may have differing effects on the neurotransmitter systems that they act so it is not clear how much lesser or greater effect they will have on the body.
Most synthetic compounds are lipophilic (soluble in fat, and so are distributed into the brain and fatty tissues). The active ingredients in most synthetic cannabis products appear to be metabolized in the liver and excreted in the urine and faces.