2C-B: Difference between revisions

| legal            = Schedule I (United States)

| intro            = 2C-B, chemically 4-bromo-2,5-dimethoxyphenethylamine, is a synthetic psychedelic phenethylamine first prepared in 1974 by Alexander Shulgin at his home laboratory in Lafayette, California. It is the founding member of the 2C series, a family of 2,5-dimethoxy-4-substituted phenethylamines that Shulgin and his collaborators developed as variations on the mescaline skeleton. 2C-B occupies a distinctive position in the psychedelic medicine landscape: a compound with a mescaline-class structural lineage, a 5-HT2A pharmacology shared with the classical psychedelics, and a subjective character that has been described as bridging the entactogenic register of MDMA and the visionary register of the classical psychedelics. It had a brief legal-sale era in the late 1980s and early 1990s before being placed in Schedule I of the United States Controlled Substances Act, temporarily in 1994 and permanently in 1995, and in Schedule II of the United Nations Convention on Psychotropic Substances in 2001.

The compound entered psychotherapeutic underground practice in the late 1970s, where it gained a reputation as a potential adjunct to psychotherapy.<ref name="papaseit2018"/> Interest grew particularly after MDMA was placed in Schedule I, on an emergency basis in 1985 and permanently in 1988,<ref name="blok2020">Blok G. [From Adam to ecstacy; legal use of MDMA in the 1970s and 1980s]. Tijdschrift voor Psychiatrie. 2020;62(8):702-706. PMID 32816299.</ref> removing that medicine from the limited circle of therapists who had been using it adjunctively. 2C-B remained legal in the United States until 1994<ref name="fr1994"/> and, for a window of years, in much of Europe. [citation needed] During that period it was used by some therapists as an MDMA-adjacent option for couples and individual work. [citation needed] It was sold commercially as an aphrodisiac under the brand name Nexus<ref name="papaseit2018"/> and, in some accounts, the name Eroxan, with commercial sale dated to the late 1980s. [citation needed] As Nexus, 2C-B became particularly identified with South Africa, where it had a brief and conspicuous run as a legally sold aphrodisiac in the early 1990s before the South African Medicines Control Council scheduled it. [citation needed]

The full account of the synthesis, qualitative effects, and dose range was published in 1991 in Shulgin and Shulgin's PiHKAL: A Chemical Love Story, the first half of which is autobiographical and the second half of which is a methodical catalog of 179 phenethylamines that Shulgin and his collaborators synthesized and self-tested. The book included full experimental procedures and was published as a deliberate political act: Shulgin held a Drug Enforcement Administration analytical license to possess and study scheduled compounds, and chose to make the chemistry public knowledge in the conviction that the information should not be the property of governments. In 1994 a DEA inspection of his laboratory ended with Shulgin surrendering that license, an episode Ann Shulgin recounts in the opening chapter of the companion volume TiHKAL.<ref name="tihkal-invasion">Shulgin A, Shulgin A. TIHKAL: The Continuation. Berkeley, CA: Transform Press; 1997. Chapter 1, "Invasion".</ref>

The United States Drug Enforcement Administration placed 2C-B in Schedule I on a temporary, emergency basis in January 1994,<ref name="fr1994">Drug Enforcement Administration. Schedules of Controlled Substances: Temporary Placement of 4-Bromo-2,5-dimethoxyphenethylamine Into Schedule I. Final Rule. Federal Register. 1994 Jan 6;59:671.</ref> and made the placement permanent in 1995.<ref name="fr1995">Drug Enforcement Administration. Schedules of Controlled Substances; Placement of 4-Bromo-2,5-Dimethoxyphenethylamine Into Schedule I. Final Rule. Federal Register. 1995 Jun 2;60:28718.</ref> The United Nations Convention on Psychotropic Substances added it to Schedule II in 2001.<ref name="papaseit2018"/> Most other jurisdictions scheduled the compound on similar timelines. For roughly a decade after the US scheduling, 2C-B circulated as a clandestine product in European and South American party scenes, often sold as MDMA or under one of the brand names that survived the legal sale era. In the 2010s and 2020s a small body of formal clinical research has emerged: an observational study at the Universitat Autònoma de Barcelona reported the acute pharmacology of oral 2C-B in experienced users,<ref name="papaseit2018">Papaseit E, Farré M, Pérez-Mañá C, Torrens M, et al. Acute Pharmacological Effects of 2C-B in Humans: An Observational Study. Frontiers in Pharmacology. 2018;9:206. PMID 29593537.</ref> and groups at Maastricht University and the University of Basel have begun controlled comparisons of 2C-B with psilocybin and MDMA.

2C-B is a Schedule I controlled substance in the United States with no approved medical use and no legal supply chain that guarantees product identity or purity; in modern markets it is frequently misrepresented as MDMA or substituted with other compounds, including the structurally similar but pharmacologically distinct DOB. Onset after oral administration is typically 45-75 minutes; the long onset combined with the steep dose-response curve drives a common harm pattern in which inexperienced users redose during the onset window and overshoot the intended dose. Combinations with serotonergic medicines (SSRIs, SNRIs, MAOIs, tramadol, lithium, dextromethorphan) carry serotonin syndrome risk and should be avoided; combinations with stimulants increase cardiovascular load. The general harm-reduction principles for psychedelic experiences (set, setting, sober companion, advance arrangement of supportive contacts) apply to 2C-B as they do to other 5-HT2A agonists.

| pharmacodynamics  = 2C-B is a partial agonist at the serotonin 5-HT2A receptor, with additional activity at 5-HT2C and 5-HT2B and weak inhibition of monoamine transporters.<ref name="nichols2016">Nichols DE. Psychedelics. Pharmacological Reviews. 2016;68(2):264-355. PMID 26841800.</ref> The pharmacological profile is intermediate between the classical 5-HT2A psychedelics such as LSD and psilocybin and the entactogens such as MDMA. The 5-HT2A action is the principal driver of the psychedelic component; the transporter activity may contribute to the entactogenic character at lower doses. Oral 2C-B has an onset of roughly 45 to 75 minutes and a duration of approximately four to eight hours, which is shorter than psilocybin and considerably shorter than LSD. The compound is structurally a phenethylamine in the mescaline lineage rather than a tryptamine; the 4-bromo substituent on the 2,5-dimethoxyphenethylamine scaffold confers substantially higher 5-HT2A affinity than mescaline's 3,4,5-trimethoxy parent compound, accounting for the dose-potency difference.

* '''Serotonergic medicines: serotonin syndrome risk.''' Concurrent use of SSRIs, SNRIs, MAOIs, tramadol, lithium, dextromethorphan, or other strongly serotonergic agents carries serotonin syndrome risk and should be avoided. MAOI co-administration is particularly dangerous.

* '''Stimulants: additive cardiovascular load.''' 2C-B itself produces modest sympathomimetic effects (elevated heart rate, mild blood pressure increase); concurrent stimulants compound the cardiovascular burden.

* '''CYP interactions: not well characterized.''' Human metabolism of 2C-B has not been comprehensively studied. In vitro work suggests CYP2D6 and CYP3A4 involvement; strong inhibitors of these enzymes may increase 2C-B exposure.