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Flubromazepam

Flubromazepam molecule structureFlubromazepam molecule structure
7-Bromo-5-(2-fluorophenyl)-1,3-dihydro-2H-1,4-benzodiazepin-2-one
Iso-flubromazepam (alternate isomer)
Chemical Class
Benzodiazepine

Flubromazepam is a long-lasting benzodiazepine1 that produces anxiolytic, sedative, muscle relaxant, and amnesic effects. Originally synthesized in 1960, it was never marketed and received no further attention until it resurfaced in late 2012 as an online research chemical. It has not been formally studied, meaning its pharmacological profile remains largely speculative, based on its subjective effects and structural similarities to other benzodiazepines.

Dosage & Duration

Dosage

Doses are population estimates that vary widely between individuals.

Threshold~2 mg
Light2-4 mg
Moderate4-8 mg
Strong8-12 mg
Heavy12+ mg

Duration

Onset15-90 minutes
After Effects36+ hours
Total12-18 hours
Half-life
106 hours1

Subjective Effects

Legacy content. A statistically backed ontology from Mindstate Design Labs is coming soon.

Effects vary widely by individual, dose, and context.

Physical

The physical effects of flubromazepam can be broken down into several components which progressively intensify proportional to dosage.

Motor control lossRespiratory depressionDizzinessMuscle relaxation

Cognitive

The cognitive effects of flubromazepam can be broken down into several components which progressively intensify proportional to dosage. The general head space of flubromazepam is described by many as one of intense sedation and decreased inhibition. It contains a large number of typical depressant cognitive effects.

AmnesiaAnxiety suppressionThought decelerationDisinhibitionInformation processing suppressionEuphoriaCompulsive redosing
Forked from Subjective Effect Documentation byJosie Kins August 2015.

Reagent Testing

Expected colorimetric results for common reagent tests. Colors show reaction change over 1–2 minutes.

Mecke(ME)
white → brown3
Liebermann(LB)
white → yellow2
Froe(FR)
white → yellow1
Zimm(ZI)
white → pink1 → purple2
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Pharmacology

Pharmacodynamics

Flubromazepam has not been formally studied in pharmacological research, and its mechanism of action is inferred from its structural similarity to other benzodiazepines. Like other members of its class, it is expected to act as a positive allosteric modulator at the benzodiazepine binding site of GABA-A receptors, enhancing the inhibitory activity of gamma-aminobutyric acid (GABA) in the central nervous system.2 The anticonvulsant properties observed with benzodiazepines may also involve binding to voltage-dependent sodium channels.

Pharmacokinetics

In a self-administration study in Germany of 4mg flubromazepam, serum samples showed a Tmax of 6 hours and Cmax of of 78ng/ml. The T1/2 was calculated to be roughly 106 hours. Urine samples showed signals corresponding to two monohydroxylated metabolites and one debrominated monohydroxylated metabolite. The author proposes predominant hydroxylation most likely occurs at the 3-position of the molecule leading to 3-hydroxy-flubromazepam. However, no unambiguous assessment of the position of hydroxylation was done via NMR. In the precipitated urine samples, signals corresponding to the glucuronidated main monohydroxy metabolite and the glucuronidated debrominated monohydroxylated metabolite were detected. Analysis of the samples resulting from the in vitro metabolism studies with HLM also confirmed the formation the same metabolites, suggesting the observed metabolic phase I reactions being catalyzed by CYP450 enzymes.citation needed

Interactions

Dangerous

Highest risk

These combinations are considered extremely harmful and should always be avoided. Reactions to these drugs taken in combination are highly unpredictable and have a potential to cause death.

AlcoholGHB/GBLOpioidsTramadol

Unsafe

Avoid

There is considerable risk of physical harm when taking these combinations, they should be avoided where possible.

DiphenhydraminePCP

Caution

Use caution

These combinations are not usually physically harmful, but may produce undesirable effects, such as physical discomfort or overstimulation. Extreme use may cause physical health issues. Synergistic effects may be unpredictable. Care should be taken when choosing to use this combination.

DXMKetamineMXE
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Tolerance

Tolerance timelines are rules of thumb, not exact schedules, and vary widely between individuals and use patterns.

Full Tolerance
Tolerance to sedative-hypnotic effects can appear after only several days of uninterrupted flubromazepam use.
Cross Tolerance

Benzodiazepines

Baseline Reset
Tolerance typically returns to baseline within 7-14 days after cessation. However, following prolonged or intensive use, this recovery period may extend significantly longer in proportion to the duration and intensity of prior consumption.

Harm Potential

Addiction & Dependence

Psychological

Extremely High

Flubromazepam is described as extremely psychologically addictive.citation needed Compulsive redosing is common, driven by rapid anxiety relief followed by quick offset. Memory suppression can lead to users forgetting prior doses, potentially resulting in dangerous amnesic blackout states.

Physical

Extremely High

Flubromazepam is extremely physically addictive with severe withdrawal risk. Abrupt discontinuation after regular use can be life-threatening, potentially causing seizures or death.3 Safe cessation requires gradual tapering over weeks.

Psychosis Risk

Paradoxical reactions including aggression, violent behavior, and loss of impulse control occur rarely (below 1% in the general population),4 with greater frequency among recreational abusers, individuals with mental disorders, children, and those on high-dose regimens.

Seizure Risk

Flubromazepam has anticonvulsant properties during active use. Paradoxical increased seizures are rarely reported in epileptic individuals. Abrupt discontinuation after regular use poses significant seizure risk, as benzodiazepine withdrawal seizures can be life-threatening.3

History & Culture

Flubromazepam is a benzodiazepine derivative first synthesized in 1960.citation needed Despite being developed during a period of active benzodiazepine research that produced many compounds which would eventually reach clinical use, flubromazepam was never marketed and received…

Legality

By Country

Illegal1
United States flagUnited StatesUnscheduled (Federal); Schedule I (Virginia)
Controlled / restricted6
Canada flagCanadaSchedule IV CDSA
Germany flagGermanyAnlage II BtMG
Russia flagRussiaSchedule III
Switzerland flagSwitzerlandVerzeichnis E
Turkey flagTurkeyControlled
United Kingdom flagUnited KingdomClass C

References

Source Pages

  1. Bluelight Drug Info: Flubromazepam
  2. Bluelight: Flubromazepam Discussion Thread
  3. Erowid Experience: An Assessment of Numerous Benzodiazepines
  4. Isomer Design (TiHKAL/PiHKAL)
  5. PsychonautWiki
  6. TripSit Factsheet: Flubromazepam
  7. TripSit Factsheets
  8. Wikipedia

Citations

  1. Moosmann B, Huppertz LM, Hutter M, Buchwald A, Ferlaino S, & Auwärter V. (2013). Detection and identification of the designer benzodiazepine flubromazepam and preliminary data on its metabolism and pharmacokinetics. Journal of Mass Spectrometry, 48(11), 1150-1159. https://doi.org/10.1002/jms.327912
  2. Bonano JS, & Banks ML. (2022). Novel Designer Benzodiazepines: Comprehensive Review of Evolving Clinical and Adverse Effects. https://pmc.ncbi.nlm.nih.gov/articles/PMC9397074/1
  3. Fluyau D, Revadigar N, & Manobianco BE. (2018). Challenges of the pharmacological management of benzodiazepine withdrawal, dependence, and discontinuation. Therapeutic Advances in Psychopharmacology. https://doi.org/10.1177/204512531775334012
  4. Mancuso CE, Tanzi MG, & Gabay M. (2004). Paradoxical aggressive reactions to benzodiazepine use: a review. Pharmacotherapy. https://pubmed.ncbi.nlm.nih.gov/18922233/1
  5. Controlled Drugs and Substances Act, Schedule IV, Item 18 — Benzodiazepines. Government of Canada, Department of Justice (1996). https://laws-lois.justice.gc.ca/eng/acts/c-38.8/page-12.html1
  6. Anlage II BtMG. (2019). https://www.gesetze-im-internet.de/btmg_1981/anlage_ii.html1
  7. Russian Federation Government Decree No. 681 (List III) — Fluorobromazepam, introduced by Decree No. 827 of 12 July 2017. Astrakhan State Medical University (official Russian controlled substances list republication) (2017). https://astgmu.ru/wp-content/uploads/2025/01/111.pdf1
  8. April 2017 — Several countries place benzodiazepine derivatives under national control. United Nations Office on Drugs and Crime (UNODC) Laboratory and Scientific Service (2017). https://www.unodc.org/LSS/Announcement/Details/065118d5-b238-48d8-9d7f-b95fb5d114111
  9. Turkish Council of Ministers Decision No. 2016/9712 — Control of Certain Substances under Law No. 2313. T.C. Resmî Gazete (Turkish Official Gazette), 12 January 2017 (2017). https://www.resmigazete.gov.tr/eskiler/2017/01/20170112-8.pdf1
  10. The Misuse of Drugs Act 1971 (Amendment) Order 2017 (SI 2017/634), Article 5(h). UK legislation.gov.uk (2017). https://www.legislation.gov.uk/uksi/2017/634/made/data.htm1

Further Reading

  1. Drug-Do: Benzos
  2. Hong et al. (2022) - Flubromazepam Cardiotoxicity Study
  3. Tripsitter: Flubromazepam Harm Reduction Guide
  4. UK Assessment of NPS Benzodiazepines - Abouchedid et al. (2018)

Article Status

  • Josie Kins avatar
    Step 1 · Automated synthesis

    An autonomous workflow built by Josie Kins compiled this article's foundation from information published across the web.

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    Step 2 · First-pass review

    A first pass manual review and edit of article prose and copy has been performed by subject-matter expert Lyrea. This does not guarantee factual accuracy. An additional human review for each of this article's citations is yet to be performed.

  • Step 3 · Citation reviewPending

    No one has reviewed this article's citations yet. That second pass checks each claim against the source it cites.

Recent changes8 human edits · latest

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20 August 2026

  1. Lyrea · Reworded 2 words in Pharmacology › Pharmacokinetics

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  3. Lyrea · Added a citation and reworded 32 words in Pharmacology › Pharmacokinetics

  4. Lyrea · Edited in Pharmacology › Pharmacokinetics

  5. Lyrea · Added a citation in Dosage & Duration › Routes 1 › Half life

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