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Opioid

U-47700

Also called Pink

Original Wikipedia articleen.wikipedia.org/wiki/U-47700 revision used (24 October 2026)

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Common dose · Insufflated6–8 mg PW
Onset5–10 minutes PW
Total2–3 hours PW
After-effects2–4 hours PW

Dosage

Insufflated

SourceThresholdLightCommonStrongHeavy
PsychonautWiki1 mg PW4–6 mg PW6–8 mg PW8–10 mg PW10 mg+ PW

Oral

SourceThresholdLightCommonStrongHeavy
TripSit–5–7.5 mg TS7.5–15 mg TS15–25 mg TS25 mg+ TS

TripSit dose text

TripSit's factsheet also states its doses as text.

Oral Light: 5-7.5mg Common: 7.5-15mg Strong: 15-25mg Heavy: 25+mg. TS

What dose are you on? (self-reported, unverified)
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Duration

Route · sourceOnsetCome-upPeakOffsetTotalAfter-effects
Insufflated · PsychonautWiki5–10 minutes PW15–20 minutes PW1–2 hours PW–2–3 hours PW2–4 hours PW

TripSit factsheet

Onset
Insufflated: 15 minutes · Intravenous: 0-1 minutes · Oral: 15 minutes · Rectal: 15 minutes TS
Duration
Insufflated: 3-4 hours · Intravenous: 1-2 hours · Oral: 5-7 hours · Rectal: 3-4 hours TS
Aftereffects
1-4 hours TS

Mixing

For best safety practice, don't mix this drug with other depressants.

Why: respiratory depression. PsychonautWiki says:

Quotes from PsychonautWiki, CC BY-SA 4.0.

Acute combinations: what happens when these are taken close together. Entries backed by a medical journal or agency are listed first.

Backed by medical journals

Awaiting sourcePeer-reviewed reports on acute combinations, from PubMed and the journals the harm reduction sites cite.

PsychonautWiki also lists dangerous combinations shared across a whole group (opioids) in a table this page does not copy. Read that list on PsychonautWiki.

TripSit combination chart

TripSit rates each pairing. Only pairings with a number carry a citation from TripSit. See the whole chart; TripSit's own notes are on combo.tripsit.me.

Dangerous

alcohol TScocaine TSdextromethorphan TSketamine TSmxe TStramadol TS

Caution

nitrous TSpcp TS

Low Risk & Synergy

cannabis TS

Low Risk & No Synergy

amt TScaffeine TSdmt TSlsd TSmdma TSmescaline TSmushrooms TS

Risks and toxicity

U-47700 has a high toxicity relative to its dose due to its extreme potency. As with all opioids, long-term effects can vary but can include diminished libido, apathy and memory loss. It is also potentially lethal when mixed with depressants like alcohol or benzodiazepines. PW

It is worth noting that U-47700 crystals are particularly corrosive and somewhat caustic to mucous membranes. Careless use may deteriorate the chosen routes of administration so it is important to practice routine maintenance such as soaking the sinus cavity with water prior to and following insufflation. Even if following a regular saline wash of the nasal cavity, multiday use of this substance can create bleeding sores and scabs in the septum and nasal lining. These scabs may persist for days even after all use is ceased. It is unwise to vaporize the substance as it can damage the lungs. Sublingual administration is likely to damage the skin in the mouth. PW

Combined consumption of U-47700 and fentanyl caused one fatality in Belgium. At least 17 opioid overdoses and several deaths in the USA have also been connected with the use of U-47700.[21][22] PW

It is strongly recommended that one use harm reduction practices, and take extreme caution when using this substance. PW

Tolerance and addiction potential

As with other opioids, the chronic use of U-47700 can be considered moderately addictive with a high potential for abuse and is capable of causing psychological dependence among certain users. When addiction has developed, cravings and withdrawal symptoms may occur if a person suddenly stops their usage. PW

Tolerance to many of the effects of U-47700 develops with prolonged and repeated use. The rate at which this occurs develops at different rates for different effects, with tolerance to the constipation-inducing effects developing particularly slowly for instance. This results in users having to administer increasingly large doses to achieve the same effects. After that, it takes about 3 - 7 days for the tolerance to be reduced to half and 1 - 2 weeks to be back at baseline (in the absence of further consumption). U-47700 presents cross-tolerance with all other opioids, meaning that after the consumption of U-47700 all opioids will have a reduced effect. PW

U-47700 withdrawal symptoms can be especially painful and emerge after 2-4 hours after the last dose administration. It is highly advisable not to become physically dependent on this substance, as physical dependence can develop in a short period. PW

The risk of fatal opioid overdoses rise sharply after a period of cessation and relapse, largely because of reduced tolerance. To account for this lack of tolerance, it is safer to only dose a fraction of one's usual dosage if relapsing. It has also been found that the environment one is in can play a role in opioid tolerance. In one scientific study, rats with the same history of heroin administration were significantly more likely to die after receiving their dose in an environment not associated with the drug in contrast to a familiar environment.[23][24] PW

TripSit factsheet

Avoid
All other CNS depressants TS

Testing

Awaiting sourceReagent reactions and test kit guidance from a harm reduction testing service.

Effects

EuphoriaDry MouthMood liftItchinessRelaxantConstipationPupil constrictionAnalgesia TS

Overview

U-47700 is a synthetic opioid substance of the benzamide chemical class that produces analgesic, relaxing, sedating and euphoric effects when administered.[1] PW

A µ-opioid receptor agonist that is related to AH-7921. Having a very short duration. TS

U-47700, also known as U4, pink heroin, pinky, and pink, is an opioid analgesic drug developed by a team at Upjohn in the 1970s which has around 7.5 times the potency of morphine in animal models.[2–5] WP

U-47700 is a structural isomer of the earlier opioid AH-7921 and the result of a great deal of work elucidating the quantitative structure–activity relationship of the scaffold. Upjohn looked for the key moieties which gave the greatest activity and posted over a dozen patents on related compounds, each optimizing one moiety until they discovered that U-47700 was the most active.[6–16] WP

U-47700 became the lead compound of selective kappa-opioid receptor ligands such as U-50488, U-51754 (containing a pyrrolidine rather than a dimethylamine substituent) and U-69,593, which share very similar structures. Although not used medically, the selective kappa ligands are used in research.[17–20] WP

History

In popular culture

U-47700 is the title of a 2021 Dutch sci-fi short film by director Erasmo de la Parra. In the film, the characters are addicted to a new drug containing the substance U-47700.[25] WP

Pharmacology

Pharmacology

U-47700 is an agonist of the μ-opioid receptor (Kᵢ 11.1 ± 0.4 nM) and possesses significantly lower affinity for the κ-opioid receptor (Kᵢ = 287 ± 24 nM) and δ-opioid receptor (Kᵢ = 1220 ± 82 nM). U-47700 is approximately 10-fold more potent than morphine in rats, although the binding of U-47700 is 2–4 times weaker than morphine at all three opioid receptors.[44] WP

The metabolism of U-47700 in humans involves mono- and didesmethylation followed by hydroxylation. The desmethyl metabolites of U-47700 have negligible affinity for the opioid receptors and are not thought to contribute to the activity of U-47700.[44][45][46] WP

Detection in biological fluids

U-47700 may be measured in serum, plasma, blood or urine to monitor for abuse, confirm a diagnosis of poisoning, or assist in a medicolegal death investigation. Serum or blood U-47700 concentrations are expected to be in a range of 10–250 μg/L in intoxicated patients and 100–1,500 μg/L in deceased victims of acute overdosage. The detection usually involves analysis by liquid chromatography-mass spectrometry.[47] WP

Chemistry

Formula
C16H22Cl2N2O PC
Molar mass (g/mol)
329.3 PC
IUPAC name (computed by PubChem)
3,4-dichloro-N-[(1R,2R)-2-(dimethylamino)cyclohexyl]-N-methylbenzamide PC
SMILES
CN(C)[C@@H]1CCCC[C@H]1N(C)C(=O)C2=CC(=C(C=C2)Cl)Cl PC
InChIKey
JGPNMZWFVRQNGU-HUUCEWRRSA-N PC
PubChem CID
13544016

User reports

Erowid erowid.org

Listings

Erowid Experience Vault listing

Link as published on TripSit's factsheet.

Top stories
Awaiting sourceShort summaries of the most-read reports, each linked, saying only what the report says.

Bluelight bluelight.org

Listings
Awaiting sourceTrip report threads and this substance's discussion forum.
Top stories
Awaiting sourceShort summaries of the most-read reports, each linked, saying only what the report says.

Reddit reddit.com

Listings
Awaiting sourceTrip report posts and the relevant subreddits.
Top stories
Awaiting sourceShort summaries of the most-read reports, each linked, saying only what the report says.

Pop culture

No references added yet.

Add a reference

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References

  1. Other U-47700 at DistilBio
  2. Other Szmuszkovicz J. Patent US4098904 - Analgesic N-(2-aminocycloaliphatic)benzamides. 4 July 1978
  3. Journal / agency Cheney BV, Szmuszkovicz J, Lahti RA, Zichi DA. Factors affecting binding of trans-N-[2-(methylamino)cyclohexyl]benzamides at the primary morphine receptor. Journal of Medicinal Chemistry. December 1985. doi:10.1021/jm00150a017 · PMID 2999404
  4. Journal / agency Harper NJ, Veitch GB, Wibberley DG. 1-(3,4-Dichlorobenzamidomethyl)cyclohexyldimethylamine and related compounds as potential analgesics. Journal of Medicinal Chemistry. November 1974. doi:10.1021/jm00257a012 · PMID 4416926
  5. Journal / agency Szmuszkovicz J, Von Voigtlander PF. Benzeneacetamide amines: structurally novel non-m mu opioids. Journal of Medicinal Chemistry. October 1982. doi:10.1021/jm00352a005 · PMID 6128415
  6. Journal / agency Brittain RT, Kellett DN, Neat ML, Stables R. Proceedings: Anti-nociceptive effects in N-substituted cyclohexylmethylbenzamides. British Journal of Pharmacology. September 1973. doi:10.1111/j.1476-5381.1973.tb08279.x · PMID 4207044 · PMC1776456
  7. Journal / agency Michalson ET, Szmuszkovicz J. Progress in Drug Research. Progress in Drug Research. Fortschritte der Arzneimittelforschung. Progres des Recherches Pharmaceutiques. 1989. doi:10.1007/978-3-0348-9146-2_6 · PMID 2687936
  8. Other Mullins DD. Patent US US3258489 - N-(1-aminocyclohexylmethyl)anilines and N-(1-nitrocyclohexylmethyl)anilines. 28 June 1966
  9. Other Harper NJ, Veitch GB. Patent US3975443 - 1-(3,4-dichlorobenzamidomethyl)-cyclohexyldimethylamine. 17 August 1976
  10. Other Szmuszkovicz J. Patent US3499033 - Ethers of α-phenyl-2-aminocycloalkanemethanols. 3 March 1970
  11. Other Szmuszkovicz J. Patent US3510492 - 2-anilino and 2-anilinomethyl cycloalkylamines. 5 May 1970
  12. Other Rynbrandt RH, Skaletzky LL. Patent US3647804 - Cycloalkanecarboxamides. 7 March 1972
  13. Other Roll W. Patent US3825595 - N-cyclopentyl-N-2-hydroxyalkyl-ring-substituted benzamides. 23 July 1974
  14. Other Harper NJ, Veitch GB. Patent US4049663 - Ethylene diamine derivatives. 20 September 1977
  15. Other Collins RJ, Kaplan LJ, Ludens JH, Von Voigtlander PF. Patent US4463013 - Oxygen substituted amino-cyclohexyl-benzeneacetamides and -benzamides as water diuretic drugs. 9 April 1982
  16. Journal / agency Casy AF, Parfitt RT. Opioid Analgesics. 1986. doi:10.1007/978-1-4899-0585-7_11
  17. Journal / agency Szmuszkovicz J, Zhao S, Totleben MJ, Mizsak SA, Freeman JP. Phenanthridone Analogs of the Opiate Agonist U-47,700 in the trans-1,2-Diaminocyclohexane Benzamide Series. Heterocycles. 2000. doi:10.3987/com-99-s27
  18. Journal / agency Loew G, Lawson J, Toll L, Frenking G, Berzetei-Gurske I, Polgar W. Structure activity studies of two classes of beta-amino-amides: the search for kappa-selective opioids. NIDA Research Monograph. 1988. PMID 2855852
  19. Journal / agency Szmuszkovicz J. Progress in Drug Research. Progress in Drug Research. Fortschritte der Arzneimittelforschung. Progres des Recherches Pharmaceutiques. 1999. doi:10.1007/978-3-0348-8730-4_4 · PMID 10396128
  20. Journal / agency Tsibulnikov SY, Maslov LN, Mukhomedzyanov AV, Krylatov AV, Tsibulnikova MR, Lishmanov YB. Prospects of Using of κ-Opioid Receptor Agonists U-50,488 and ICI 199,441 for Improving Heart Resistance to Ischemia/Reperfusion. Bulletin of Experimental Biology and Medicine. October 2015. doi:10.1007/s10517-015-3057-8 · PMID 26519268
  21. Other NWS, V. Twee doden in België door overdosis met fentanylpleisters. 2016
  22. Other Zalkind, S. Synthetic opiate makers stay step ahead of US drug laws as overdose cases rise. 2016
  23. Other Why Heroin Relapse Often Ends In Death - Lauren F Friedman (Business Insider)
  24. Journal / agency Siegel, S., Hinson, R. E., Krank, M. D., McCully, J. Heroin “Overdose” Death: Contribution of Drug-Associated Environmental Cues. Science. 23 April 1982. doi:10.1126/science.7200260
  25. Other Filmaffinity U-47700 (S) (2021)
  26. Other https://www.ris.bka.gv.at/Dokumente/BgblAuth/BGBLA_2019_II_167/BGBLA_2019_II_167.pdfsig
  27. Other http://portal.anvisa.gov.br/documents/33868/3233596/55+-+RDC+N%C2%BA+143-2017-DOU.pdf/de80dc69-acb4-48b3-a6ac-1198993b0c1e
  28. Other Lääkeaineluettelo
  29. Other Anlage II BtMG - Einzelnorm
  30. Other Постановление Правительства РФ от 01.10.2012 N 1002 (ред. от 09.08.2019) “Об утверждении значительного, крупного и особо крупного размеров наркотических средств и психотропных веществ, а также значительного, крупного и особо крупного размеров для растений, содержащих наркотические средства или психотропные вещества, либо их частей, содержащих наркотические средства или психотропные вещества, для целей статей 228, 228.1, 229 и 229.1 Уголовного кодекса Российской Федерации” - КонсультантПлюс
  31. Other https://www.folkhalsomyndigheten.se/nyheter-och-press/nyhetsarkiv/2015/november/31-nya-amnen-kan-klassas-som-narkotika-eller-halsofarlig-vara/
  32. Other Verordnung des EDI über die Verzeichnisse der Betäubungsmittel, psychotropen Stoffe, Vorläuferstoffe und Hilfschemikalien
  33. Other The Misuse of Drugs Act 1971 (Amendment) Order 2017
  34. Other Executive Order 2016-01K
  35. Other Schedules of Controlled Substances: Temporary Placement of U-47700 Into Schedule I
  36. Other [email protected], A. C.-. 463/2013 Sb. Nařízení vlády o seznamech návykových látek
  37. Journal / agency Pinky
  38. Other Kasich JR. Executive Order 2016-01K. May 3, 2016
  39. Other News Release - Attorney General Bondi Outlaws Deadly Synthetic Drug
  40. Other DEA Public Affairs. 46 confirmed deaths linked to dangerous opioid in '15 and '16 spark emergency action. November 11, 2016
  41. Other Schedules of Controlled Substances: Placement of Butyryl Fentanyl and U-47700 Into Schedule I. 20 April 2018
  42. Other South Dakota Legislature. House Bill No. 1041
  43. Other EXPLANATORY MEMORANDUM TO THE MISUSE OF DRUGS ACT 1971 (AMENDMENT) ORDER 2017
  44. Journal / agency Truver MT, Smith CR, Garibay N, Kopajtic TA, Swortwood MJ, Baumann MH. Pharmacodynamics and pharmacokinetics of the novel synthetic opioid, U-47700, in male rats. Neuropharmacology. October 2020. doi:10.1016/j.neuropharm.2020.108195 · PMID 32533977 · PMC7554234
  45. Journal / agency Krotulski AJ, Mohr AL, Papsun DM, Logan BK. Metabolism of novel opioid agonists U-47700 and U-49900 using human liver microsomes with confirmation in authentic urine specimens from drug users. Drug Testing and Analysis. January 2018. doi:10.1002/dta.2228 · PMID 28608586
  46. Journal / agency Nordmeier F, Cannaert A, Stove CP, Schmidt PH, Meyer MR, Schaefer N. Are the N-demethylated metabolites of U-47700 more active than their parent compound? In vitro μ-opioid receptor activation of N-desmethyl-U-47700 and N,N-bisdesmethyl-U-47700. Drug Testing and Analysis. April 2022. doi:10.1002/dta.3182 · PMID 34669261
  47. Other Baselt, R. (2017) Disposition of Toxic Drugs and Chemicals in Man, 11th edition, Biomedical Publications, Foster City, CA, pp. 2208

Text and values on this page are quoted from PsychonautWiki (CC BY-SA 4.0), Wikipedia (CC BY-SA 4.0), TripSit factsheets, PubChem (public domain). Each value links to the exact revision it came from.