WARNINGDANGER OF DEATH

Most cases of fatal overdose occur when depressants like opioids are combined with other depressants such as alcohol, benzodiazepines or gabapentinoids. It is highly discouraged to combine these substances.

Furanylfentanyl

Fu-F

Psychoactive Class

Opioid Depressant

Chemical Class

Anilinopiperidine (opioid)

Furanylfentanyl is a potent synthetic opioid analgesic of the anilinopiperidine class and a structural analogue of fentanyl.¹² Classified as a research chemical, it has extremely limited pharmacological and toxicological documentation available. It is thought to be somewhat less potent and shorter-acting than butyrfentanyl. Due to the scarcity of reliable information and its high potency, exercising extreme caution with this substance is strongly recommended.

Dosage & Duration

Dosage

Threshold~200 µg

Light200-400 µg

Moderate400-800 µg

Strong800-1600 µg

Heavy1600+ µg

Duration

Onset1-10 minutes

After Effects1-3 hours

Total1-3 hours

Subjective Effects

The experience is that of a short-acting, extremely potent opioid, dominated by analgesia, sedation, and the characteristic opioid sense of physical and emotional comfort. Its effects closely mirror those of fentanyl itself, though it is roughly half as potent and believed to be somewhat shorter in duration than related analogs such as butyrfentanyl. The margin between an active dose and dangerous respiratory depression is narrow, and sensory alteration beyond bodily sensation is minimal.

Physical

Physical effects follow the fentanyl-analog pattern: pain relief and heavy sedation accompanied by itching and nausea, with potentially life-threatening respiratory depression at higher doses.

Sedation

Uncomfortable

Nausea

Cognitive

The headspace is one of opioid sedation and relief, with little in the way of complex cognitive alteration reported.

Reagent Testing

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

Marquis(MQ)

Mecke(ME)

Mandelin(MD)

Liebermann(LB)

PROtestkit.eu

Pharmacology

Pharmacodynamics

Furanylfentanyl is an opioid analgesic and a structural analog of fentanyl.⁴⁵ It exhibits an ED50 of 0.02 mg/kg in mice, and in humans it has been estimated to be 50 to 100 times more potent than morphine, placing it at roughly half the potency of fentanyl.

Pharmacokinetics

The metabolism of Furanylfentanyl has been characterised. Metabolites were formed via N-dealkylation, hydroxylation, amide hydrolysis followed by hydroxylation with glucuronidation or sulfation, dihydrodiol formation followed by hydroxylation or N-dealkylation, oxidative N-dealkylation and reduction of the keto group, and furanyl ring opening and carboxylation.⁶

Metabolitesnone documented yet

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.

AlcoholBenzodiazepinesCocaineDXMGHB/GBLKetamineMXEPregabalinTramadol

Unsafe

Avoid

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

Diphenhydramine

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.

AmphetaminesMAOIsMephedroneNitrous oxidePCP

TripSit

Tolerance

Cross Tolerance

Opioids (full cross-tolerance expected with all μ-opioid receptor agonists)

Harm Potential

Addiction & Dependence

Psychological

High

Classified as habit-forming. As a potent fentanyl analog, it carries significant risk of psychological dependence consistent with other opioids.⁷

Toxicity

Respiratory

Potentially serious respiratory depression can occur at active doses and is life-threatening; this is the primary mechanism of fatal opioid overdose and represents the most significant acute risk with this substance.⁷

History & Culture

Furanylfentanyl was first characterized during research conducted in the 1980s, when studies in humans demonstrated it to be approximately 50 to 100 times more potent than morphine, placing it at roughly half the potency of fentanyl.¹⁰ Despite this early…

Legality

International

Furanylfentanyl is included in Schedule I of the 1961 Single Convention on Narcotic Drugs. UNODC records its scheduling year as 2018.

By Country

United StatesIllegalSchedule I (DEA drug code 9834)

Schedule I, Controlled Substances Act; 21 CFR 1308.11(b)²⁰²¹

Furanyl fentanyl is expressly listed as a Schedule I opiate in the current 21 CFR 1308.11(b), under DEA drug code 9834. DEA's permanent final order placed it in Schedule I effective 29 November 2018; its prior placement had been temporary.

BrazilIllegalLista F1

ANVISA RDC No. 227 of 17 May 2018¹⁴

Brazil placed furanilfentanil, the Portuguese name used for furanylfentanyl, on ANVISA's Lista F1 in RDC No. 227 of 17 May 2018. Lista F1 is the list of proscribed substances.

NetherlandsIllegalFuranylfentanyl

Opiumwet, lijst I¹⁷

Furanylfentanyl staat als zelfstandige vermelding op lijst I bij de Opiumwet. Artikel 2 van de Opiumwet verbiedt onder meer het binnen of buiten Nederland brengen, verkopen, aanwezig hebben en vervaardigen van middelen op lijst I.

UkraineIllegalList No. 1

Cabinet of Ministers Resolution No. 770, Table I, List No. 1¹⁹

Furanylfentanyl (Fu-F; Furanyl fentanyl) is expressly listed in Table I, List No. 1 of the controlled-substances list approved by Cabinet Resolution No. 770. List No. 1 designates especially dangerous narcotic drugs whose circulation is prohibited. The current official text retains the Furanylfentanyl entry and identifies it as N-феніл-N-[1-(2-фенілетил)піперидин-4-іл]фуран-2-карбоксамід.

AustraliaIllegalSchedule 9 — Prohibited substances

Therapeutic Goods (Poisons Standard—June 2026) Instrument 2026 (F2026L00633), Schedule 9¹²¹³

Furanylfentanyl is expressly listed in Schedule 9 of the current, in-force Poisons Standard. The Federal Register records F2026L00633 as registered and effective on 28 May 2026. Schedule 9 is the domestic scheduling classification; it recommends prohibition of manufacture, possession, supply and use except for approved medical or scientific research, analytical, teaching or training purposes. The separate Customs (Prohibited Imports) Regulations 1956 border-control listing is not used as the canonical domestic status.

GermanyRestrictedAnlage II · Non-prescribable

Betäubungsmittelgesetz (BtMG), Anlage II (zu § 1 Abs. 1)¹⁵¹⁶

Furanylfentanyl (FU-F) is expressly listed in Anlage II to the current consolidated BtMG. Anlage II is the category for marketable narcotics that are not prescribable; traffic is subject to the BtMG authorisation regime, so the status is not prohibited.

SwedenIllegalBilaga 1 — smärtstillande medel

Förordning (1992:1554) om kontroll av narkotika, bilaga 1¹⁸

Furanylfentanyl (Fu-F) is expressly listed in the current consolidated Annex 1 to Sweden's narcotics-control ordinance. Substances in that annex are deemed narcotics under the Narcotics Penal Law. The inspected current official source does not establish the claimed 25 January 2017 effective date.

References

Source Pages

Citations

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