Naphyrone, also known as O-2482 and naphthylpyrovalerone, is a substituted cathinone drug derived from

pyrovalerone (Centroton, 4-Methyl-β-keto-prolintane, Thymergix, O-2371) is a psychoactive drug with stimulant effects via acting as a norepinephrine-dopamine reuptake inhibitor (NDRI), and is used for the clinical treatment of chronic fatigue or letharg ...

that acts as a triple reuptake inhibitor, producing

stimulant Stimulants (also often referred to as psychostimulants or colloquially as uppers) is an overarching term that covers many drugs including those that increase activity of the central nervous system and the body, drugs that are pleasurable and inv ...

effects and has been reported as a novel

designer drug A designer drug is a structural or functional analog of a controlled substance that has been designed to mimic the pharmacological effects of the original drug, while avoiding classification as illegal and/or detection in standard drug tests. D ...

. No safety or toxicity data is available on the drug. 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, 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.

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 Mephedrone, also known as , , and , is a synthetic stimulant drug of the amphetamine and cathinone classes. Slang names include drone, , White Magic, meow meow, bubble, ''txomin'' and yurrpt. It is chemically similar to the cathinone compounds ...

(which was also a

cathinone Cathinone (also known as benzoylethanamine, or β-keto-amphetamine) is a monoamine alkaloid found in the shrub ''Catha edulis'' (khat) and is chemically similar to ephedrine, cathine, methcathinone and other amphetamines. It is probably the mai ...

derivative). Until July 2010 the substance was not controlled by the

Misuse of Drugs Act 1971 The Misuse of Drugs Act 1971 is an Act of the Parliament of the United Kingdom. It represents action in line with treaty commitments under the Single Convention on Narcotic Drugs, the Convention on Psychotropic Substances, and the United Nati ...

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. 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 Methylenedioxypyrovalerone (MDPV) is a stimulant of the cathinone class that acts as a norepinephrine–dopamine reuptake inhibitor (NDRI). It was first developed in the 1960s by a team at Boehringer Ingelheim. Its activity at the dopamine tra ...

flephedrone Flephedrone, also known as 4-fluoromethcathinone (4-FMC), is a stimulant drug of the cathinone chemical class that has been sold online as a designer drug starting in 2008. Toxicity Flephedrone has only a short history of human use and its t ...

butylone Butylone, also known as β-keto-''N''-methylbenzodioxolylbutanamine (βk-MBDB), is an entactogen, psychedelic, and stimulant psychoactive drug of the phenethylamine chemical class. It is the β-keto (substituted cathinone) analogue of MBDB and ...

and

caffeine Caffeine is a central nervous system (CNS) stimulant of the methylxanthine chemical classification, class. It is mainly recreational drug use, used recreationally as a Nootropic, cognitive enhancer, increasing alertness and attentional perfor ...

, one product tested was

inorganic In chemistry, an inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds, that is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as ''inorganic chemist ...

in composition. 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, following a report from the

Advisory Council on the Misuse of Drugs The Advisory Council on the Misuse of Drugs (ACMD) is a British statutory advisory non-departmental public body, which was established under the Misuse of Drugs Act 1971. Mandate Its terms of reference, according to the Act, are as follows: '' ...

Pharmacology

As a triple reuptake inhibitor, naphyrone has been shown ''

in vitro ''In vitro'' (meaning in glass, or ''in the glass'') studies are performed with microorganisms, cells, or biological molecules outside their normal biological context. Colloquially called " test-tube experiments", these studies in biology a ...

'' to affect the

reuptake Reuptake is the reabsorption of a neurotransmitter by a neurotransmitter transporter located along the plasma membrane of an axon terminal (i.e., the Synapse, pre-synaptic neuron at a synapse) or glial cell after it has performed its function of ...

of the

neurotransmitter A neurotransmitter is a signaling molecule secreted by a neuron to affect another cell across a synapse. The cell receiving the signal, any main body part or target cell, may be another neuron, but could also be a gland or muscle cell. Neu ...

serotonin Serotonin () or 5-hydroxytryptamine (5-HT) is a monoamine neurotransmitter. Its biological function is complex and multifaceted, modulating mood, cognition, reward, learning, memory, and numerous physiological processes such as vomiting and va ...

dopamine Dopamine (DA, a contraction of 3,4-dihydroxyphenethylamine) is a neuromodulatory molecule that plays several important roles in cells. It is an organic chemical of the catecholamine and phenethylamine families. Dopamine constitutes about 80% o ...

and

norepinephrine Norepinephrine (NE), also called noradrenaline (NA) or noradrenalin, is an organic chemical in the catecholamine family that functions in the brain and body as both a hormone and neurotransmitter. The name "noradrenaline" (from Latin '' ad ...

by interacting with the

serotonin transporter The serotonin transporter (SERT or 5-HTT) also known as the sodium-dependent serotonin transporter and solute carrier family 6 member 4 is a protein that in humans is encoded by the SLC6A4 gene. SERT is a type of monoamine transporter protein tha ...

(SERT),

dopamine transporter The dopamine transporter (also dopamine active transporter, DAT, SLC6A3) is a membrane-spanning protein that pumps the neurotransmitter dopamine out of the synaptic cleft back into cytosol. In the cytosol, other transporters sequester the dop ...

(DAT), and norepinephrine transporter (NET). One study found that the

dissociation constant In chemistry, biochemistry, and pharmacology, a dissociation constant (K_D) is a specific type of equilibrium constant that measures the propensity of a larger object to separate (dissociate) reversibly into smaller components, as when a complex ...

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

analogues tested, naphyrone was found to be the only triple reuptake inhibitor found to be active at n M concentrations. Some samples of β-naphyrone sold have also been found to contain the alternative

isomer In chemistry, isomers are molecules or polyatomic ions with identical molecular formulae – that is, same number of atoms of each element – but distinct arrangements of atoms in space. Isomerism is existence or possibility of isomers. Is ...

α-naphyrone, presumably produced accidentally as an impurity in synthesis. 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.

References

{{Phenethylamines Cathinones Stimulants Pyrrolidinophenones 2-Naphthyl compounds Serotonin–norepinephrine–dopamine reuptake inhibitors Designer drugs Propyl compounds

Use in the United Kingdom

Pharmacology

See also

References