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Kudlacek O, Hofmaier T, Luf A, Mayer FP, Stockner T, Nagy C, Holy M, Freissmuth M, Schmid R, Sitte HH. Cocaine adulteration. J Chem Neuroanat 2017; 83-84:75-81. [PMID: 28619473 DOI: 10.1016/j.jchemneu.2017.06.001] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Revised: 05/03/2017] [Accepted: 06/10/2017] [Indexed: 12/20/2022]
Abstract
Cocaine is a naturally occurring and illicitly used psychostimulant drug. Cocaine acts at monoaminergic neurotransmitter transporters to block uptake of the monoamines, dopamine, serotonin and norepinephrine. The resulting increase of monoamines in the extracellular space underlies the positively reinforcing effects that cocaine users seek. In turn, this increase in monoamines underlies the development of addiction, and can also result in a number of severe side effects. Currently, cocaine is one of the most common illicit drugs available on the European market. However, cocaine is increasingly sold in impure forms. This trend is driven by cocaine dealers seeking to increase their profit margin by mixing ("cutting") cocaine with numerous other compounds ("adulterants"). Importantly, these undeclared compounds put cocaine consumers at risk, because consumers are not aware of the additional potential threats to their health. This review describes adulterants that have been identified in cocaine sold on the street market. Their typical pharmacological profile and possible reasons why these compounds can be used as cutting agents will be discussed. Since a subset of these adulterants has been found to exert effects similar to cocaine itself, we will discuss levamisole, the most frequently used cocaine cutting agent today, and its metabolite aminorex.
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Affiliation(s)
- Oliver Kudlacek
- Medical University Vienna, Center for Physiology and Pharmacology, Institute of Pharmacology, Waehringerstrasse 13a, 1090 Vienna, Austria
| | - Tina Hofmaier
- Medical University Vienna, Center for Physiology and Pharmacology, Institute of Pharmacology, Waehringerstrasse 13a, 1090 Vienna, Austria
| | - Anton Luf
- Medical University of Vienna, Clinical Department of Laboratory Medicine, Waehringer Guertel 18-20, 1090 Vienna, Austria
| | - Felix P Mayer
- Medical University Vienna, Center for Physiology and Pharmacology, Institute of Pharmacology, Waehringerstrasse 13a, 1090 Vienna, Austria
| | - Thomas Stockner
- Medical University Vienna, Center for Physiology and Pharmacology, Institute of Pharmacology, Waehringerstrasse 13a, 1090 Vienna, Austria
| | - Constanze Nagy
- checkit!-Suchthilfe Wien gGmbH, Gumpendorferstraße8, 1060 Vienna, Austria
| | - Marion Holy
- Medical University Vienna, Center for Physiology and Pharmacology, Institute of Pharmacology, Waehringerstrasse 13a, 1090 Vienna, Austria
| | - Michael Freissmuth
- Medical University Vienna, Center for Physiology and Pharmacology, Institute of Pharmacology, Waehringerstrasse 13a, 1090 Vienna, Austria
| | - Rainer Schmid
- Medical University of Vienna, Clinical Department of Laboratory Medicine, Waehringer Guertel 18-20, 1090 Vienna, Austria
| | - Harald H Sitte
- Medical University Vienna, Center for Physiology and Pharmacology, Institute of Pharmacology, Waehringerstrasse 13a, 1090 Vienna, Austria; Center for Addiction Research and Science - Medical University Vienna, Waehringerstrasse 13A, 1090 Vienna, Austria.
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Hofmaier T, Luf A, Seddik A, Stockner T, Holy M, Freissmuth M, Ecker GF, Schmid R, Sitte HH, Kudlacek O. Aminorex, a metabolite of the cocaine adulterant levamisole, exerts amphetamine like actions at monoamine transporters. Neurochem Int 2013; 73:32-41. [PMID: 24296074 PMCID: PMC4077236 DOI: 10.1016/j.neuint.2013.11.010] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Revised: 11/22/2013] [Accepted: 11/24/2013] [Indexed: 11/17/2022]
Abstract
We quantified adulterants in street drugs sold as cocaine. We analyzed effects of the most common adulterant levamisole, on neurotransmitter transporters. Differences in the selectivity of levamisole can be explained by homology modelling and docking. Aminorex, a metabolite of levamisole, modulates neurotransmitter transporters directly. Depending on the transporter, aminorex acts as a blocker or as a releaser.
Psychostimulants such as amphetamine and cocaine are illicitly used drugs that act on neurotransmitter transporters for dopamine, serotonin or norepinephrine. These drugs can by themselves already cause severe neurotoxicity. However, an additional health threat arises from adulterant substances which are added to the illicit compound without declaration. One of the most frequently added adulterants in street drugs sold as cocaine is the anthelmintic drug levamisole. We tested the effects of levamisole on neurotransmitter transporters heterologously expressed in HEK293 cells. Levamisole was 100 and 300-fold less potent than cocaine in blocking norepinephrine and dopamine uptake, and had only very low affinity for the serotonin transporter. In addition, levamisole did not trigger any appreciable substrate efflux. Because levamisole and cocaine are frequently co-administered, we searched for possible allosteric effects; at 30 μM, a concentration at which levamisole displayed already mild effects on norepinephrine transport it did not enhance the inhibitory action of cocaine. Levamisole is metabolized to aminorex, a formerly marketed anorectic drug, which is classified as an amphetamine-like substance. We examined the uptake-inhibitory and efflux-eliciting properties of aminorex and found it to exert strong effects on all three neurotransmitter transporters in a manner similar to amphetamine. We therefore conclude that while the adulterant levamisole itself has only moderate effects on neurotransmitter transporters, its metabolite aminorex may exert distinct psychostimulant effects by itself. Given that the half-time of levamisole and aminorex exceeds that of cocaine, it may be safe to conclude that after the cocaine effect “fades out” the levamisole/aminorex effect “kicks in”.
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Affiliation(s)
- Tina Hofmaier
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Waehringerstrasse 13A, 1090 Vienna, Austria
| | - Anton Luf
- Clinical Department of Laboratory Medicine, Medical University of Vienna, Waehringer Guertel 10-20, 1090 Vienna, Austria
| | - Amir Seddik
- University of Vienna, Department of Medicinal Chemistry, Althanstrasse 14, 1090 Vienna, Austria
| | - Thomas Stockner
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Waehringerstrasse 13A, 1090 Vienna, Austria
| | - Marion Holy
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Waehringerstrasse 13A, 1090 Vienna, Austria
| | - Michael Freissmuth
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Waehringerstrasse 13A, 1090 Vienna, Austria
| | - Gerhard F Ecker
- University of Vienna, Department of Medicinal Chemistry, Althanstrasse 14, 1090 Vienna, Austria
| | - Rainer Schmid
- Clinical Department of Laboratory Medicine, Medical University of Vienna, Waehringer Guertel 10-20, 1090 Vienna, Austria
| | - Harald H Sitte
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Waehringerstrasse 13A, 1090 Vienna, Austria.
| | - Oliver Kudlacek
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Waehringerstrasse 13A, 1090 Vienna, Austria
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Abstract
This review summarizes the neurochemical, therapeutic and adverse effects of serotonin (5-HT) releasing agents. The 5-HT releaser (plus minus)-fenfluramine is composed of two stereoisomers, (+)-fenfluramine and (minus sign)-fenfluramine, which are N-de-ethylated to yield the metabolites, (+)-norfenfluramine and (minus sign)-norfenfluramine. Fenfluramines and norfenfluramines are 5-HT transporter substrates and potent 5-HT releasers. Other 5-HT releasing agents include m-chlorophenylpiperazine (mCPP), a major metabolite of the antidepressant drug trazodone. Findings from in vitro and in vivo studies support the hypothesis that fenfluramines and mCPP release neuronal 5-HT via a non-exocytotic carrier-mediated exchange mechanism involving 5-HT transporters. (+)-Norfenfluramine is a potent 5-HT(2B) and 5-HT(2C) receptor agonist. The former activity may increase the risk of developing valvular heart disease (VHD), whereas the latter activity is implicated in the anorectic effect of systemic fenfluramine. Anorectic agents that increase the risk of developing primary pulmonary hypertension (PPH) share the common property of being 5-HT transporter substrates. However, these drugs vary considerably in their propensity to increase the risk of PPH. In this regard, neither trazodone nor mCPP is associated with PPH. Similarly, although some 5-HT substrates can deplete brain 5-HT (fenfluramine), others do not (mCPP). In addition to the established indication of obesity, 5-HT releasers may be helpful in treating psychiatric problems such as drug and alcohol dependence, depression and premenstrual syndrome. Viewed collectively, it seems possible to develop new medications that selectively release 5-HT without the adverse effects of PPH, VHD or neurotoxicity. Such agents may have utility in treating a variety of psychiatric disorders.
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Affiliation(s)
- Richard B Rothman
- Clinical Psychopharmacology Section, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, P.O. Box 5180, 5500 Nathan Shock Drive, Baltimore, MD 21224, USA.
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