Clinical data
ATC code
  • none
Legal status
Legal status
  • (RS)-1-naphthalen-2-yl-2-pyrrolidin-1-ylpentan-1-one
CAS Number
PubChem CID
CompTox Dashboard (EPA)
Chemical and physical data
Molar mass281.399 g·mol−1
3D model (JSmol)
  • CCCC(C(C1=CC2=C(C=C1)C=CC=C2)=O)N3CCCC3

Naphyrone, also known as O-2482 and naphthylpyrovalerone,[3] is a substituted cathinone drug derived from pyrovalerone that acts as a triple reuptake inhibitor,[4] producing stimulant effects and has been reported as a novel designer drug.[5] No safety or toxicity data is available on the drug.[6]

The drug has been marketed under the name NRG-1, although only a minority of samples of substances sold under this name have been found to actually contain naphyrone,[7][8][9] and even samples that proved to contain genuine β-naphyrone were in some cases also found to contain the 1-naphthyl isomer α-naphyrone in varying proportions, further confusing the reported effects profile.[10][11]

Use in the United Kingdom

Naphyrone emerged as a new legal high in the United Kingdom only months after the ban of similar drug mephedrone (which was also a cathinone derivative). Until July 2010 the substance was not controlled by the Misuse of Drugs Act 1971 and was therefore not illegal for someone to possess. The Medicines Act prevented naphyrone from being sold for human consumption, and therefore it was sometimes sold as 'pond cleaner' or as another substance not normally consumed by humans.[citation needed]

A study by researchers at Liverpool John Moores University found that only one out of ten products labelled as "NRG-1" actually contained naphyrone when they were subjected to laboratory analysis. Compounds found in products labelled NRG-1 included MDPV, flephedrone, mephedrone, butylone and caffeine, one product tested was inorganic in composition.[7] In the case of an individual possessing a product labelled NRG-1 that contains MDPV or other illegal substances, they are in possession of a controlled substance.

On 12 July 2010, the Home Office announced that naphyrone had been banned and made a Class B drug,[12] following a report from the Advisory Council on the Misuse of Drugs.[13][14][15]


As a triple reuptake inhibitor, naphyrone has been shown in vitro to affect the reuptake of the neurotransmitters serotonin, dopamine and norepinephrine by interacting with the serotonin transporter (SERT), dopamine transporter (DAT), and norepinephrine transporter (NET).

One study found that the dissociation constant of naphyrone interacting with SERT is 33.1nM ± 1.1, with DAT is 20.1nM ± 7.1 and with NET is 136nM ± 27. The concentration of naphyrone required to inhibit the transporters by 50% is 46.0nM ± 5.5 for SERT, 40.0nM ± 13 for DAT and 11.7nM ± 0.9 for NET. Of a number of pyrovalerone analogues tested, naphyrone was found to be the only triple reuptake inhibitor found to be active at nM concentrations.[4]

Some samples of β-naphyrone sold have also been found to contain the alternative isomer α-naphyrone,[16] presumably produced accidentally as an impurity in synthesis.[17][failed verification] The in vitro data available in the scientific literature was all obtained using pure β-naphyrone, and the pharmacological properties of α-naphyrone are unknown, further complicating the pharmacological profile of this little-studied designer drug.


See also


  1. ^ "Schedules of Controlled Substances: Temporary Placement of 10 Synthetic Cathinones Into Schedule I". Archived from the original on 2015-04-14. Retrieved 2015-04-05.
  2. ^ "Ustawa z dnia 15 kwietnia 2011 r. o zmianie ustawy o przeciwdziałaniu narkomanii ( Dz.U. 2011 nr 105 poz. 614 )". Internetowy System Aktów Prawnych. Archived from the original on June 27, 2012. Retrieved 17 June 2011.
  3. ^ "Deadly New 'Legal' Drug Bound For Britain - Yahoo! News UK". 2010-03-31. Archived from the original on April 5, 2010. Retrieved 2010-04-03.
  4. ^ a b Meltzer, PC; Butler, D; Deschamps, JR; Madras, BK (Feb 2006). "1-(4-Methylphenyl)-2-pyrrolidin-1-yl-pentan-1-one (Pyrovalerone) analogues: a promising class of monoamine uptake inhibitors". Journal of Medicinal Chemistry. 49 (4): 1420–32. doi:10.1021/jm050797a. PMC 2602954. PMID 16480278.
  5. ^ Alan Travis, home affairs editor (2010-04-01). "NRG-1 may be next legal high to face ban by ministers | Politics". The Guardian. Archived from the original on 2021-05-31. Retrieved 2010-04-03. ((cite news)): |author= has generic name (help)
  6. ^ Lavery, Michael (2 April 2010). "New 50c legal drug 'is more evil' than any head shop high". The Herald. Archived from the original on 7 April 2010. Retrieved 2 April 2010.
  7. ^ a b Brandt, S. D.; Sumnall, H. R.; Measham, F.; Cole, J. (2010). "Second generation mephedrone. The confusing case of NRG-1". BMJ. 341: c3564. doi:10.1136/bmj.c3564. PMID 20605894. S2CID 20354123.
  8. ^ Brandt SD, Sumnall HR, Measham F, Cole J (August 2010). "Analyses of second-generation 'legal highs' in the UK: initial findings". Drug Testing and Analysis. 2 (8): 377–82. CiteSeerX doi:10.1002/dta.155. PMID 20687197.
  9. ^ Wood, DM; Davies, S; Cummins, A; Button, J; Holt, DW; Ramsey, J; Dargan, PI (Dec 2011). "Energy-1 ('NRG-1'): don't believe what the newspapers say about it being legal". Emergency Medicine Journal. 28 (12): 1068–70. doi:10.1136/emj.07.2010.3184rep. PMC 3062281. PMID 22101594.
  10. ^ Brandt SD, Wootton RC, De Paoli G, Freeman S (October 2010). "The naphyrone story: The alpha or beta-naphthyl isomer?". Drug Testing and Analysis. 2 (10): 496–502. CiteSeerX doi:10.1002/dta.185. PMID 20886463.
  11. ^ De Paoli G, Maskell PD, Pounder DJ (February 2011). "Naphyrone: analytical profile of the new "legal high" substitute for mephedrone". Journal of Forensic and Legal Medicine. 18 (2): 93. doi:10.1016/j.jflm.2010.12.001. PMID 21315306.
  12. ^ "NRG-1 'legal high' drug is banned". BBC News. 2010-07-12. Archived from the original on 2021-05-31. Retrieved 2010-07-17.
  13. ^ "Advisory Council on the Misuse of Drugs Naphyrone Report (2010)". Home Office. 2010-07-07. Archived from the original on 2010-07-17. Retrieved 2010-07-17.
  14. ^ "The Misuse of Drugs (Amendment No. 2) (England, Wales and Scotland) Regulations 2010 No. 1799" (PDF). Retrieved 2010-07-18.
  15. ^ "Explanatory Memorandum To The Misuse of Drugs (Amendment No. 2) (England, Wales and Scotland) Regulations 2010 No. 1799" (PDF). Retrieved 2010-07-18.
  16. ^ Brandt, S. D.; Wootton, R. C.; De Paoli, G; Freeman, S (2010). "The naphyrone story: The alpha or beta-naphthyl isomer?". Drug Testing and Analysis. 2 (10): 496–502. CiteSeerX doi:10.1002/dta.185. PMID 20886463.
  17. ^ "An overview of new psychoactive substances and the outlets supplying them" (PDF). Ireland: National Advisory Committee on Drugs. Archived from the original (PDF) on 2011-11-25.