AM-855 is an analgesic

Analgesic

An analgesic is any member of the group of drugs used to relieve pain . The word analgesic derives from Greek an- and algos ....

 drug which is a cannabinoid agonist

Agonist

An agonist is a chemical that binds to a receptor of a cell and triggers a response by that cell. Agonists often mimic the action of a naturally occurring substance...

. It is a derivative of Δ⁸Tetrahydrocannabinol

Tetrahydrocannabinol

Tetrahydrocannabinol , also known as delta-9-tetrahydrocannabinol , Δ1-THC , or dronabinol, is the main chemical psychoactive substance found in the cannabis plant. It was first isolated in 1964. In pure form, it is a glassy solid when cold, and becomes viscous and sticky if warmed...

 with a conformationally restricted side chain which has been bound into a fourth ring fused to the aromatic A-ring of the cannabinoid skeleton. AM-855 is an agonist at both CB₁

Cannabinoid receptor type 1

The cannabinoid receptor type 1, often abbreviated to CB1, is a G protein-coupled cannabinoid receptor located in the brain. It is activated by endocannabinoid neurotransmitters including anandamide and by the compound THC, found in the psychoactive drug cannabis.-Expression:The CB1 receptor is...

 and CB₂

Cannabinoid receptor 2 (macrophage)

Cannabinoid receptor 2 , also known as CB2 or CNR2, is a G protein-coupled receptor from the cannabinoid receptor family, which in humans is encoded by the CNR2 gene...

 with moderate selectivity for CB₁, with a K_i

Dissociation constant

In chemistry, biochemistry, and pharmacology, a dissociation constant is a specific type of equilibrium constant that measures the propensity of a larger object to separate reversibly into smaller components, as when a complex falls apart into its component molecules, or when a salt splits up into...

of 22.3nM at CB₁ and 58.6nM at CB₂.