Skip to content

Batch information on every product pageTHC < 0.3%Shipped from France10% off when you sign up

Synthetic

GW842166X

A selective synthetic CB2 agonist with no activity at CB1; no demonstrated efficacy in acute dental pain.

Unscheduled
Level of detail

Harm-reduction warning

No characterised human dose: animal / in vitro data only. Effect profile, safety margin and acute toxicity are not documented in human clinical practice. Extremely potent compound: severe effects, seizures and deaths reported in the literature.

C₁₈H₁₇Cl₂F₃N₄O₂

CAS 666260-75-9

Family
Synthetic CB receptor agonistResearch ligand or medicine
Molar mass
449.30 g/mol

Updated on

In plain terms

GW842166X is a laboratory molecule with no botanical relation to hemp. A pharmaceutical company designed it to act only on the CB2 receptor, found mainly on immune cells, and not on the brain receptor responsible for the intoxicating effects of cannabis. In a controlled trial in people who had a wisdom tooth removed, it showed no clinically significant analgesic effect, unlike ibuprofen.

Receptors and activity

Target network

CB2AgonistEC50 = 63 nM · humanrecombinant CB2 expressed in yeast; efficacy 95% relative to HU-210; 91 nM at rat CB2
  • Activates

The lower the cited value, the closer the target sits to GW842166X: one ring per factor of 100. A target with no measured value stays on the edge.

Where these targets live

Where each target has been found in humans, according to the cited studies. The map shows the target, not an effect of GW842166X.

Brain, side view
Body, front view
Blood

CB2CB2 found in 5 regions of the body

  1. SpleendenseHighly abundant in the spleen1
  2. Immune cellspresentMainly B cells and natural killer cells1
  3. SkinpresentKeratinocytes, mast cells and nerve fibres2
  4. GutpresentImmune cells of the colonic mucosa3
  5. BonepresentPresent on osteoclasts4

Map sources

  1. Galiègue S et al. Expression of central and peripheral cannabinoid receptors in human immune tissues and leukocyte subpopulations. Eur J Biochem, 1995 (new tab)
  2. Ständer S et al. Distribution of cannabinoid receptor 1 (CB1) and 2 (CB2) on sensory nerve fibers and adnexal structures in human skin. J Dermatol Sci, 2005 (new tab)
  3. Wright K et al. Differential expression of cannabinoid receptors in the human colon: cannabinoids promote epithelial wound healing. Gastroenterology, 2005 (new tab)
  4. Rossi F et al. The endovanilloid/endocannabinoid system in human osteoclasts: possible involvement in bone formation and resorption. Bone, 2009 (new tab)

Cited values

  1. CB2AgonistEC50 = 63 nM · human53 out of 100

    Giblin et al., J Med Chem 2007 (ChEMBL values from the document) (new tab) · recombinant CB2 expressed in yeast; efficacy 95% relative to HU-210; 91 nM at rat CB2

  2. CB1Agonistno measured value cited
Bar length follows the measured value (Ki, Kd, EC50 or IC50), on one scale shared by every entry, from 100 µM to 0.1 nM. A target with no cited value has no bar.

Pharmacology

GW842166X is a selective synthetic agonist of the cannabinoid CB2 receptor, from a series of pyrimidine-5-carboxamides optimised by GlaxoSmithKline. It activates human CB2 with a median effective concentration of 63 nM and an efficacy of 95% of that of HU-210, and rat CB2 with 91 nM, whereas no activity is measured at CB1 up to more than 30,000 nM (Giblin et al. 2007). In rats it is active orally in the complete Freund's adjuvant model of inflammatory pain, with an ED50 of 0.1 mg/kg; its oral bioavailability is 58% and its half-life 3 hours (ChEMBL values, Giblin 2007). Later academic work attributes to it effects on chondrocyte catabolism in a mouse model of osteoarthritis (Huang et al. 2022) and a neuroprotective effect in a mouse model of Parkinson's disease (Yu et al. 2021). In humans, in a controlled trial after wisdom-tooth extraction, GW842166 showed no clinically significant analgesia at two dose levels, whereas the comparator ibuprofen was superior to placebo on all endpoints; the treatments were well tolerated (Ostenfeld et al. 2011). A phase II trial in knee osteoarthritis was registered, with no result found. No therapeutic benefit is established in humans.

Key sources.

History

Source
An entirely synthetic molecule. It is present neither in Cannabis sativa nor in any known living organism, and shares no structural kinship with the plant cannabinoids. It is a pharmacological tool of the endocannabinoid system, born of an industrial medicinal-chemistry programme targeting the CB2 receptor alone.

Origin

Laboratory synthesis

No biosynthetic pathway: the molecule has no natural equivalent and comes exclusively from organic synthesis, by assembling a trifluoromethylated pyrimidine ring, a dichlorinated aniline and an amine derived from tetrahydropyran.

Classification

Family, origin and source verification

Family

Synthetic CB receptor agonist › Research ligand or medicine

Class

pyrimidine-5-carboxamide

Verification

Classification, sources and binding values checked on 20 October 2026; text read against its sources and Wikipedia.

Wikipedia (English)

GW-842,166X (new tab)

Article paired by the molecule's structure (InChIKey), revision read on 19 October 2026. Read as a second opinion, never cited as a source.

References

  1. Giblin GM et al., Discovery of 2-[(2,4-dichlorophenyl)amino]-N-[(tetrahydro-2H-pyran-4-yl)methyl]-4-(trifluoromethyl)-5-pyrimidinecarboxamide, a selective CB2 receptor agonist for the treatment of inflammatory pain, J Med Chem 2007;50(11):2597-2600 (new tab)PMID 17477516
  2. Ostenfeld T et al., A randomized, controlled study to investigate the analgesic efficacy of single doses of the cannabinoid receptor-2 agonist GW842166, ibuprofen or placebo in patients with acute pain following third molar tooth extraction, Clin J Pain 2011;27(8):668-676 (new tab)PMID 21540741
  3. ChEMBL, measured activity data for GW842166X at CB1 and CB2 (CHEMBL225411) (new tab)
  4. ClinicalTrials.gov, NCT00447486, A Study of GW842166 in Adults With Osteoarthritis Pain (phase II, GlaxoSmithKline) (new tab)
  5. Grossman S, Tan H, Gadiwalla Y, Cannabis and orofacial pain: a systematic review, Br J Oral Maxillofac Surg 2022 (new tab)PMID 35305839
  6. Yu H et al., The Neuroprotective Effects of the CB2 Agonist GW842166x in the 6-OHDA Mouse Model of Parkinson's Disease, Cells 2021;10(12):3548 (new tab)PMID 34944056
  7. Huang WR et al., GW842166X Alleviates Osteoarthritis by Repressing LPS-mediated Chondrocyte Catabolism in Mice, Curr Med Sci 2022 (new tab)PMID 36178576
  8. Rakotoarivelo V et al., The Impact of the CB2 Cannabinoid Receptor in Inflammatory Diseases: An Update, Molecules 2024;29(14):3381 (new tab)PMID 39064959

Identifiers

Names

IUPAC name
2-(2,4-dichloroanilino)-N-(oxan-4-ylmethyl)-4-(trifluoromethyl)pyrimidine-5-carboxamide
Other names
GW842166 · GW-842166X

Identifiers

Formula
C₁₈H₁₇Cl₂F₃N₄O₂
CAS
666260-75-9
PubChem CID
10253143(new tab)
InChIKey
TWQYWUXBZHPIIV-UHFFFAOYSA-N
SMILES
C1COCCC1CNC(=O)C2=CN=C(N=C2C(F)(F)F)NC3=C(C=C(C=C3)Cl)Cl

Machine-readable entry (JSON)

LLM ingestion format: a structured superset of the entry (identifiers, binding, versioned legal status). Full corpus.