title: The hidden web and the fentanyl problem: Detection of ocfentanil as an adulterant in heroin.
abstract: The popularization of anonymous markets such as Silk Road is challenging current drug policy and may provide a new context for old issues, such as adulteration of heroin with fentanyl derivatives. The aims of this paper are to report the presence of ocfentanil, a novel, potent, non-controlled fentanyl analog, in samples sold as heroin in the hidden web, and to summarize the effects reported by users.
  
  
  
  In 2015, four samples allegedly bought as heroin in cryptomarkets of the hidden web were sent to Energy Control for analysis. Energy Control is a Spanish harm reduction NGO that offers anonymous drug checking with the purpose of adapting counselling to the specific substances present in the drug and monitor the drug market. Identification was performed by GC/MS and LC/MS/MS. We contacted the submitters of the samples and performed an Internet search to retrieve additional information.
  
  
  
  One sample contained ocfentanil, caffeine and heroin. Three samples contained the aforementioned substances plus paracetamol. Two out of the four contacted users reported distinct short acting, opioid-like effects. No fora discussion could be found about the effects of ocfentanil, neither web pages nor individuals advertising the substance.
  
  
  
  We report the presence of a new substance detected in the hidden web as an adulterant of heroin, ocfentanil. It has short acting opioid-like effects, roughly the same potency as fentanyl, and can be injected, snorted or smoked. Severe side effects have been associated with its use, including one death. No discussion about this substance could be found in the Internet, which suggests this substance has not been sold as such. Available data about purities of drugs purchased in cryptomarkets suggest that adulteration is not a severe problem and this agrees with users' perceptions. However, this study suggests that adulteration is a real threat not only at the street level, but also for users that buy substances in cryptomarkets, and suggest the need for harm reduction initiatives in this setting.
authors.affiliation: Energy Control, Associació Benestar i Desenvolupament, Barcelona, Spain; Hospital del Mar Medical Research Institute-IMIM, Barcelona, Spain.
authors.forename: Pol
authors.initials: P
authors.lastname: Quintana
authors.affiliation: Energy Control, Associació Benestar i Desenvolupament, Barcelona, Spain; Hospital del Mar Medical Research Institute-IMIM, Barcelona, Spain. Electronic address: mireia@energycontrol.org.
authors.forename: Mireia
authors.initials: M
authors.lastname: Ventura
authors.affiliation: Energy Control, Associació Benestar i Desenvolupament, Barcelona, Spain; Hospital del Mar Medical Research Institute-IMIM, Barcelona, Spain; Institut de Neuropsiquiatria i Addiccions, Hospital del Mar. Parc de Salut Mar, Barcelona, Spain.
authors.forename: Marc
authors.initials: M
authors.lastname: Grifell
authors.affiliation: Hospital del Mar Medical Research Institute-IMIM, Barcelona, Spain; Institut de Neuropsiquiatria i Addiccions, Hospital del Mar. Parc de Salut Mar, Barcelona, Spain.
authors.forename: Alvaro
authors.initials: A
authors.lastname: Palma
authors.affiliation: Hospital del Mar Medical Research Institute-IMIM, Barcelona, Spain; Institut de Neuropsiquiatria i Addiccions, Hospital del Mar. Parc de Salut Mar, Barcelona, Spain.
authors.forename: Liliana
authors.initials: L
authors.lastname: Galindo
authors.affiliation: Energy Control, Associació Benestar i Desenvolupament, Barcelona, Spain.
authors.forename: Iván
authors.initials: I
authors.lastname: Fornís
authors.affiliation: Energy Control, Associació Benestar i Desenvolupament, Barcelona, Spain.
authors.forename: Cristina
authors.initials: C
authors.lastname: Gil
authors.affiliation: Energy Control, Associació Benestar i Desenvolupament, Barcelona, Spain.
authors.forename: Xoán
authors.initials: X
authors.lastname: Carbón
authors.affiliation: Energy Control, Associació Benestar i Desenvolupament, Barcelona, Spain.
authors.forename: Fernando
authors.initials: F
authors.lastname: Caudevilla
authors.affiliation: Hospital del Mar Medical Research Institute-IMIM, Barcelona, Spain; Departament de Farmacologia, de Terapèutica i de Toxicologia, Universitat Autònoma de Barcelona, Bellaterra, Spain; Servei de Farmacologia Clínica, Hospital Universitari Germans Trías i Pujol (IGTP), Badalona, Spain.
authors.forename: Magí
authors.initials: M
authors.lastname: Farré
authors.affiliation: Hospital del Mar Medical Research Institute-IMIM, Barcelona, Spain; Institut de Neuropsiquiatria i Addiccions, Hospital del Mar. Parc de Salut Mar, Barcelona, Spain; Departament de Psiquiatria, Universitat Autònoma de Barcelona, Bellaterra, Spain.
authors.forename: Marta
authors.initials: M
authors.lastname: Torrens
mesh_terms: D002110:Caffeine / Q000032:analysis; D002853:Chromatography, Liquid / Q000379:methods; D003132:Commerce; D004340:Drug Contamination; D064423:Drug Trafficking; D055030:Drug Users; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D040261:Harm Reduction; D003932:Heroin / Q000032:analysis* / Q000737:chemistry / Q000600:supply & distribution; D006801:Humans; D020407:Internet; D010880:Piperidines / Q000032:analysis*; D013030:Spain; D053719:Tandem Mass Spectrometry / Q000379:methods
chemical_list: D010880:Piperidines; D002110:Caffeine; D003932:Heroin; C071395:ocfentanil
keywords: Adulteration; Dark web; Fentanyl derivatives; Heroin; Hidden web; Ocfentanil