5-APB (5-Benzofury): Complete Toxicology, Fatalities, Dependence & Safety Monograph
What the evidence actually shows
Evidence Moderate human fatal/toxicology evidence; strong monoamine/5-HT receptor pharmacology; limited long-term/dependence dataDirect answer
Reference-grade 5-APB monograph covering identity, benzofuran history, monoamine-transporter and 5-HT2A/2B pharmacology, fatal intoxications, seizures, hyperthermia, cardiovascular risk, metabolism/testing, tolerance, stimulant/entactogen withdrawal, treatment, forensic interpretation, WHO surveillance, and legal status. 5-APB (CAS 286834-81-9) is an amphetamine-like benzofuran entactogen/stimulant that inhibits monoamine transporters and acts as a potent agonist at serotonin 5-HT2 receptors, including 5-HT2B. Direct human evidence includes fatal intoxications, mixed 3-MMC/5-APB fatality, forensic postmortem cases, and confirmed covert-administration cases. A published fatal case attributed death primarily to 5-APB after the person became unconscious and stopped breathing; measured postmortem concentration cannot be treated as a universal lethal threshold.
Research brief
Questions this page answers
- What is 5-APB or 5-benzofury?
- How does 5-APB work?
- Can 5-APB cause serotonin syndrome or hyperthermia?
- Has 5-APB caused deaths?
- What does 5-HT2B agonism mean for 5-APB?
- Can 5-APB cause tolerance or dependence?
- What does 5-APB withdrawal or comedown look like?
- How is 5-APB detected in blood or urine?
- Can laboratories distinguish 5-APB from 6-APB?
- Is 5-APB internationally controlled?
Signal
Scientific takeaways
- 5-APB (CAS 286834-81-9) is an amphetamine-like benzofuran entactogen/stimulant that inhibits monoamine transporters and acts as a potent agonist at serotonin 5-HT2 receptors, including 5-HT2B.
- Direct human evidence includes fatal intoxications, mixed 3-MMC/5-APB fatality, forensic postmortem cases, and confirmed covert-administration cases.
- A published fatal case attributed death primarily to 5-APB after the person became unconscious and stopped breathing; measured postmortem concentration cannot be treated as a universal lethal threshold.
- 5-APB/6-APB pharmacology includes potent 5-HT2B agonism, raising a theoretical concern about chronic valvular/cardiac effects; there is no human longitudinal 5-APB study establishing incidence.
- Acute toxicity can include agitation, seizures, hypertension, tachycardia, hyperthermia, bradycardia/cardiovascular collapse, altered consciousness, and serotonergic/sympathomimetic features.
- 5-APB and 6-APB are positional isomers that require analytical separation; product labels and generic mass spectra can misidentify benzofuran contents.
- Repeated monoaminergic stimulant/entactogen use can produce tolerance, craving and post-use fatigue/depressed mood, but no validated 5-APB-specific dependence or withdrawal timeline exists.
- WHO has kept 5-APB under surveillance since 2017; as of October 2, 2026 it is not internationally scheduled through the ECDD process.
5-APB (5-Benzofury): Complete Toxicology, Fatalities, Dependence & Safety Monograph
Emergency entactogen/stimulant toxicity: Seizure, dangerous overheating, severe agitation/confusion, chest pain, collapse, very fast/irregular heartbeat, loss of consciousness, or severe muscle rigidity/clonus after an unknown stimulant/entactogen requires urgent medical care.
Quick answer
5-APB is 5-(2-aminopropyl)benzofuran, an MDMA/MDA-like benzofuran entactogen-stimulant with substantial serotonergic and catecholaminergic pharmacology.
Unlike many obscure NPS, it has direct human fatality evidence.
Published cases document:
- isolated/predominant fatal 5-APB intoxication;
- mixed 5-APB + 3-MMC + alcohol fatality;
- seizures;
- hyperthermia;
- major cardiovascular instability;
- unconsciousness;
- covert/unintended administration.
Identity
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| Field | Evidence-based answer |
|---|---|
| Canonical name | 5-(2-Aminopropyl)benzofuran (5-APB) |
| Common name | 5-Benzofury |
| CAS | 286834-81-9 |
| Formula / molecular mass | C11H13NO / 175.23 g/mol |
| Class | Benzofuran entactogen / amphetamine-type stimulant |
| Main pharmacology | Monoamine transporter inhibition/release + serotonergic receptor agonism |
| Approved medical use | None |
| WHO status | Under surveillance; no international scheduling status |
History
5-APB was described in scientific/medicinal-chemistry work before appearing as a recreational NPS around 2010.
Its market history overlaps with:
- 6-APB;
- 5-/6-APDB;
- 5-MAPB;
- 6-MAPB.
The similarity of names and structures creates recurring analytical and product-label confusion.
Pharmacology
5-APB affects all three major monoamine systems:
- serotonin;
- dopamine;
- norepinephrine.
In-vitro research shows:
- monoamine transporter inhibition;
- monoamine-releasing properties;
- high-affinity serotonin receptor binding.
5-HT2A and 5-HT2B activity
5-APB shows agonist activity at:
- 5-HT2A — relevant to psychedelic/perceptual effects;
- 5-HT2B — relevant to potential cardiac-valvular biology;
- 5-HT2C.
Why 5-HT2B deserves attention
Chronic activation of 5-HT2B receptors by some medications has been linked with cardiac valvulopathy.
5-APB is a potent 5-HT2B agonist in vitro.
What is not established is the incidence of valve disease after intermittent or repeated 5-APB use.
The receptor finding warrants caution—not a claim that every user develops valvular damage.
Human acute toxicity
Clinical and forensic reports describe:
- agitation;
- hypertension;
- tachycardia;
- hyperthermia;
- seizures;
- altered consciousness;
- cardiovascular collapse.
The syndrome can overlap with sympathomimetic and serotonergic toxicity.
Fatal 5-APB intoxication
A 2018 report described a 25-year-old man who became unconscious and stopped breathing.
5-APB was the major toxicological finding, with low-level ethanol and THC.
The cause of death was attributed to 5-APB.
What one fatality cannot establish
The measured blood concentration is not a universal lethal threshold.
Individual susceptibility, timing and postmortem factors remain important.
Additional fatality evidence
A 2015 U.S. forensic case reported 5-APB in a young adult death with little other toxicology beyond alcohol.
Another case involved 3-MMC + 5-APB + alcohol and featured agitation, seizures, hypertension, tachycardia, hyperthermia and later cardiovascular collapse.
That mixed case cannot isolate one drug as the sole driver.
Serotonin toxicity
5-APB's serotonergic pharmacology makes serotonin toxicity biologically plausible.
Warning features can include:
- agitation;
- hyperthermia;
- clonus/hyperreflexia;
- autonomic instability;
- altered mental status.
Not every severe 5-APB poisoning necessarily meets formal serotonin-syndrome criteria.
Hyperthermia and seizures
Dangerous overheating and seizures can cause secondary:
- rhabdomyolysis;
- metabolic acidosis;
- kidney injury;
- cardiovascular collapse.
These complications are medical emergencies.
Cardiovascular risk
Potential acute effects include hypertension, tachycardia, arrhythmia and cardiovascular collapse.
Long-term cardiovascular effects of 5-HT2B agonism remain unquantified in humans.
Drug-facilitated/unintended exposure
A 2022 report documented three women with 5-APB identified in urine after suspected hidden administration at a dance club.
This proves a person can encounter 5-APB without knowingly choosing it.
Interactions
No controlled interaction study establishes safe combinations.
Highest concerns include:
- MAO inhibitors;
- serotonergic stimulants/entactogens;
- other sympathomimetics;
- alcohol/sedatives;
- unknown polysubstance products.
Metabolism and pharmacokinetics
Published reviews describe metabolism and detectability, but there is no robust controlled human 5-APB PK program.
No universal half-life, time-to-peak, safe concentration, or accumulation curve has been established.
Testing and analytical toxicology
5-APB vs 6-APB
These positional isomers can be difficult to distinguish if a method lacks adequate chromatographic separation.
Modern HPLC-MS/MS methods can quantify/differentiate them in blood, urine, hair and tissues.
Routine screens
Standard amphetamine immunoassays may cross-react unpredictably and cannot identify 5-APB specifically.
Definitive mass spectrometry is more reliable.
Product identity
Products marketed as “benzofury,” MDMA, or a specific APB can contain 5-APB, 6-APB, APDB compounds, MAPB compounds, or mixtures.
A label is not analytical confirmation.
Tolerance
Repeated serotonergic/stimulant exposure can produce tolerance.
No controlled 5-APB human tolerance study establishes a timeline or cross-tolerance ratio.
Escalation can increase cardiovascular, hyperthermic, serotonergic and psychiatric risk.
Dependence and stimulant/entactogen use disorder
5-APB-specific dependence epidemiology is sparse.
Its dopamine/serotonin/norepinephrine activity gives meaningful abuse/reinforcement potential.
Problematic use can include craving, repeated redosing, binge patterns, and use despite medical harm.
Withdrawal / post-use effects
After repeated entactogen/stimulant exposure, possible symptoms include:
- fatigue;
- low mood;
- anhedonia;
- sleep disturbance;
- irritability;
- craving.
There is no validated 5-APB-specific withdrawal timeline.
Treatment and support
There is no medication approved specifically for 5-APB use disorder.
The ASAM/AAAP stimulant-use-disorder guideline identifies contingency management as a core evidence-based behavioral approach.
U.S. resources include FindTreatment.gov and SAMHSA 1-800-662-HELP (4357).
Forensic interpretation
A fatal concentration is not a personal threshold.
5-APB must be analytically distinguished from 6-APB, and mixed fatalities require case-specific attribution.
Special populations
No controlled 5-APB safety program exists for pregnancy/breastfeeding, adolescents, cardiovascular disease, seizure disorders, psychiatric illness, or significant liver/kidney disease.
The 5-HT2B signal makes repeated exposure especially uncertain in people with cardiac disease.
Legal/regulatory status — dated October 2, 2026
WHO / international
WHO added 5-APB to its surveillance list in 2017.
It was reconsidered by the ECDD working group in 2021, which found insufficient new information to justify a critical review.
WHO's current substance record lists no international scheduling status for 5-APB.
United States
This review does not identify a current federal Schedule I listing specifically naming 5-APB in the primary DEA schedules used here.
State laws and federal analogue-law questions can differ.
Myths and misconceptions
“5-APB is just safer MDMA.”
Not established; fatal intoxications exist.
“5-HT2B activity proves everyone will get heart-valve disease.”
No. It is a mechanistic concern without human incidence data.
“A fatal blood concentration gives the lethal dose.”
False.
“5-APB and 6-APB are analytically interchangeable.”
False.
“No international scheduling means WHO considers it safe.”
False. WHO keeps it under surveillance.
Evidence ledger
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| Status | Current conclusion |
|---|---|
| Established | 5-APB is a monoaminergic benzofuran entactogen/stimulant; potent 5-HT2 receptor activity exists; severe and fatal human intoxications occur; 5-/6-APB require analytical differentiation. |
| Strongly supported | Hyperthermia, seizures, cardiovascular stress, serotonergic toxicity and problematic use are meaningful hazards. |
| Uncertain | Human PK, chronic 5-HT2B cardiac risk, dependence incidence, withdrawal timing and long-term neuropsychiatric effects. |
| Not established | Safe dose, MDMA equivalence, universal fatal concentration, or 5-APB-specific treatment medication. |
Related evidence
- 6-MAPB
- 5-MAPB
- 6-APB
- 3-MMC
- 4-MMC
- Benzofurans & entactogens hub
- Substance Use, Dependence & Harm Reduction hub
Bottom line
5-APB is not just an MDMA-like research chemical.
It has real fatal human toxicology, strong serotonergic/monoaminergic pharmacology, analytical isomer problems, and a plausible chronic cardiac concern from potent 5-HT2B agonism.
The evidence is strong enough to define serious hazards—and still too incomplete to justify potency charts, safe-dose claims, or long-term reassurance.
Source ledger
References
11 sources
- 01Pharmacological profile of novel psychoactive benzofurans Rickli A, Kopf S, Hoener MC, Liechti ME · 2015In-vitroHuman-receptor/transporter pharmacologyPMID 25765500DOI 10.1111/bph.13128 PubMed →
- 02Neurochemical profiles of some novel psychoactive substances Iversen L, Gibbons S, Treble R, Setola V, Huang XP, Roth BL · 2013In-vitroHuman receptor/transporter pharmacologyPMID 23261499DOI 10.1016/j.ejphar.2012.12.006 PubMed →
- 03The psychoactive aminoalkylbenzofuran derivatives, 5-APB and 6-APB, mimic the effects of MDA on monoamine transmission Baumann MH, et al. · 2020PreclinicalMonoamine-release pharmacologyPMID 32875347 PubMed →
- 04A fatal blood concentration of 5-APB Forensic case-report authors · 2018Human fatalityForensic fatality case reportPMID 30228015 PubMed →
- 05Acute 5-(2-aminopropyl)benzofuran (5-APB) intoxication and fatality McIntyre IM, Gary RD, Trochta A, Stolberg S, Stabley R · 2015Human fatalityForensic fatality case reportPMID 25429871DOI 10.1093/jat/bku131 PubMed →
- 06Fatal intoxication with 3-MMC and 5-APB Adamowicz P, Zuba D, Byrska B · 2014Human polysubstance fatalityMixed fatal intoxication casePMID 25447185DOI 10.1016/j.forsciint.2014.10.016 PubMed →
- 07Hidden administration of 5-APB in a dancing club of New Caledonia documented by urine analysis: about 3 cases Kintz P, et al. · 2022Human analyticalDrug-facilitated exposure case seriesPMID 35672476 PubMed →
- 08Simultaneous Determination of 5- and 6-APB in Blood, Other Body Fluids, Hair and Various Tissues by HPLC-MS-MS Hofmann V, Sundermann TR, Landmann A, et al. · 2022Human specimens / method validationForensic analytical toxicologyPMID 33576419DOI 10.1093/jat/bkab018 PubMed →
- 095-APB — WHO ECDD substance record World Health Organization · 2026Authoritative referenceInternational surveillance record Source →
- 105-APB FDA Global Substance Registration System · 2026Reference databaseChemical identity authority Source →
- 11The ASAM/AAAP Clinical Practice Guideline on the Management of Stimulant Use Disorder Clinical Guideline Committee · 2024Guideline / systematic evidence reviewClinical practice guidelinePMID 38669101DOI 10.1097/ADM.0000000000001299 PubMed →