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Research tools

Surinabant

A synthetic CB1 antagonist (Sanofi), studied against smoking and then abandoned in 2008.

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.

C₂₃H₂₃BrCl₂N₄O

CAS 288104-79-0

Family
ECS pharmacological toolAntagonist or inverse agonist
Molar mass
522.30 g/mol

Updated on

In plain terms

Surinabant is a wholly artificial molecule, made in the laboratory by the Sanofi group. It has nothing to do with hemp: instead of imitating cannabis, it blocks the receptor on which THC normally binds. Studied as an aid to stopping smoking, it did not improve abstinence rates compared with placebo.

Receptors and activity

Target network

CB1AntagonistKi = 0.6 nM · ratrat brain; 3.5 nM at recombinant human CB1
  • Blocks or inhibits
  • Binds or modulates

The lower the cited value, the closer the target sits to Surinabant: 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 Surinabant.

Brain, side view
Body, front view
Blood

CB1CB1 found in 7 regions of the body

  1. Basal gangliadenseMost dense in basal ganglia outflow nuclei1
  2. CerebellumdenseVery dense in the cerebellum1
  3. HippocampusdenseVery high concentrations in the hippocampus2
  4. AmygdaladenseHigh concentrations in the amygdala2
  5. CortexpresentPresent throughout the neocortex2
  6. Adipose tissuepresentExpressed in adipose tissue3
  7. GutpresentColonic epithelium, smooth muscle and plexus4

Map sources

  1. Herkenham M et al. Cannabinoid receptor localization in brain. Proc Natl Acad Sci U S A, 1990 (new tab)
  2. Glass M et al. Cannabinoid receptors in the human brain: a detailed anatomical and quantitative autoradiographic study in the fetal, neonatal and adult human brain. Neuroscience, 1997 (new tab)
  3. Engeli S et al. Activation of the peripheral endocannabinoid system in human obesity. Diabetes, 2005 (new tab)
  4. Wright K et al. Differential expression of cannabinoid receptors in the human colon: cannabinoids promote epithelial wound healing. Gastroenterology, 2005 (new tab)

Cited values

  1. CB1AntagonistKi = 0.6 nM · rat88 out of 100

    Rinaldi-Carmona et al., J Pharmacol Exp Ther 2004 (new tab) · rat brain; 3.5 nM at recombinant human CB1

  2. CB2Binding (function not established)Ki = 400 nM40 out of 100

    Rinaldi-Carmona et al., J Pharmacol Exp Ther 2004 (new tab) · rat spleen and human CB2: low affinity

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

Surinabant (SR147778) is a selective antagonist of the cannabinoid CB1 receptor, of the diarylpyrazole family, structurally very close to rimonabant. Its affinity for CB1 is nanomolar (Ki of 0.56 nM on rat brain, 3.5 nM on human CB1) and low for CB2 (400 nM); it showed no affinity for more than 100 other targets. In mice, by mouth and with a long duration of action, it antagonises the hypothermia, analgesia and slowed gut transit induced by a cannabinoid agonist, and it reduces ethanol and sucrose consumption and food intake in mice and rats (Rinaldi-Carmona et al., J Pharmacol Exp Ther 2004, PMID 15131245). In 30 healthy volunteers, a single oral dose of 20 or 60 mg inhibited all the effects of inhaled THC, on heart rate as on central measures, without any effect of its own, whereas 5 mg had no significant effect (Klumpers et al. 2013, PMID 23278647). In the controlled smoking-cessation trial (808 participants in four groups), four-week continuous abstinence was 25.2% on placebo against 22.6%, 22.1% and 21.5% on three doses of surinabant: no improvement, only a small reduction in weight gain after quitting (Tonstad and Aubin, J Psychopharmacol 2012, PMID 22219220). No more recent trial was found.

Key sources.

History

Source
A wholly synthetic molecule, arising from Sanofi's medicinal-chemistry work on the diarylpyrazole series opened by rimonabant. It exists neither in cannabis nor in any other living organism: its existence is confined to the laboratory and to the sponsor's clinical trials.

Origin

Research tool

No natural biosynthetic pathway. Surinabant is a synthetic product of the diarylpyrazole class. It has never been isolated from a plant, a fungus or an animal tissue.

Classification

Family, origin and source verification

Family

ECS pharmacological tool › Antagonist or inverse agonist

Verification

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

Wikipedia (English)

Surinabant (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. Rinaldi-Carmona M et al., J Pharmacol Exp Ther 2004: SR147778, a new potent and selective CB1 antagonist (new tab)PMID 15131245
  2. Klumpers LE et al., Br J Clin Pharmacol 2013: surinabant inhibits the effects of THC in humans (new tab)PMID 23278647
  3. Tonstad S, Aubin HJ, J Psychopharmacol 2012: surinabant and smoking cessation (new tab)PMID 22219220
  4. Schirris TJJ et al., Sci Rep 2015: withdrawal of rimonabant for psychiatric effects (class context) (new tab)PMID 26416158
  5. ClinicalTrials.gov NCT00432575: surinabant, smoking-cessation aid (Sanofi, phase 2, 2007-2008) (new tab)
  6. PubChem, compound CID 9849616 (surinabant) (new tab)

Identifiers

Names

IUPAC name
5-(4-bromophenyl)-1-(2,4-dichlorophenyl)-4-ethyl-N-piperidin-1-ylpyrazole-3-carboxamide
Other names
SR-147778 · SR147778 · SR 147778

Identifiers

Formula
C₂₃H₂₃BrCl₂N₄O
CAS
288104-79-0
PubChem CID
9849616(new tab)
InChIKey
HMXDWDSNPRNUKI-UHFFFAOYSA-N
SMILES
CCC1=C(N(N=C1C(=O)NN2CCCCC2)C3=C(C=C(C=C3)Cl)Cl)C4=CC=C(C=C4)Br

Machine-readable entry (JSON)

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