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Fenethylline

This article is a stubmissing:
Subjective Effects
Interactions
Tolerance
Fenethylline molecule structureFenethylline molecule structure
Amphetaminoethyltheophylline
Captagon, Phenethylline, Fenetylline, Amfetyline, BiocaptonOpen in Piru
Psychoactive Class
Chemical Class

In fenethylline, amphetamine is covalently linked to theophylline via an alkyl chain.1 It was first synthesized by the German company Degussa AG in 19612 and was used to treat attention deficit hyperactivity disorder and, less commonly, narcolepsy and depression.3 It produces a smaller increase in blood pressure than an equivalent dose of amphetamine and was marketed as a milder alternative.

Dosage & Duration

Dosage

Doses are population estimates that vary widely between individuals.

Threshold10 mg
Light20-40 mg
Moderate40-100 mg
Strong100-200 mg
Heavy200+ mg
Bioavailability
39.2%

Subjective Effects

Subjective Effects not written up yet

Pharmacology

Pharmacodynamics

Fenethylline's pharmacological effects appear to arise from the combined actions of its two active stimulant metabolites, possibly involving synergy between them.4 Their respective contributions are not fully understood. Before metabolic cleavage, fenethylline appears to act directly at several serotonin receptors, although its own pharmacological actions remain poorly established.

Pharmacokinetics

Oral bioavailability is reported as 39.2%. Fenethylline can be metabolized into amphetamine (24.5% of the oral dose) and theophylline (13.7% of the oral dose).5

Interactions

Interactions not written up yet

An unlisted combination is an unknown one, not a safe one. Check a dedicated combination chart before mixing.

Check TripSit

Tolerance

Tolerance not written up yet

Harm Potential

Addiction & Dependence

Psychological

High

Fenethylline has significant abuse potential with reports of widespread addiction among user populations. Forty percent of users between ages twelve and twenty-two in one regional study were reported to be addicted, and former fighters have described becoming addicted to pills given by brigade leaders without knowing what they were taking.

Toxicity

Central Nervous System

Chronic or high-dose use has been associated with brain damage according to medical reports; the extent and reversibility of such damage is not well characterized.

Cardiovascular

As an amphetamine derivative, fenethylline may cause cardiovascular strain including elevated heart rate and blood pressure, particularly at higher doses or in combination with other stimulants.

Psychosis Risk

High

Psychosis is reported as a dangerous side effect by doctors. High doses (described as 30 or more pills) can induce violent, paranoid states with loss of emotional connection and empathy. Users have been described as experiencing 'zombie-like detachment' with blank affect and spiking heart rate. Reports describe users becoming violent, paranoid, and unafraid of anything, with a 'thirst for fighting and killing' and loss of caring about consequences.

History & Culture

Development and medical use

Fenethylline was first synthesized in 1961 by the German company Degussa AG.2 It was marketed as a psychostimulant under the names Captagon, Biocapton, and Fitton3 and was used for approximately 25 years as a milder alternative to amphetamine

Legality

International

Controlled internationally under the UN Convention on Psychotropic Substances 1971.

By Country

Illegal4
United States flagUnited StatesIllegal
Australia flagAustraliaIllegal
Canada flagCanadaIllegal
United Kingdom flagUnited KingdomIllegal
Prescription2
Brazil flagBrazilPrescription only
Germany flagGermanyPrescription only

References

Source Pages

  1. Bluelight: Fenethylline discussion thread (2014-01-13)
  2. Bluelight: Fenethylline/Captagon thread (2021-12-18)
  3. DrugBank: Fenethylline (DB01482)
  4. Isomer Design (TiHKAL/PiHKAL)
  5. PsychonautWiki
  6. Wikipedia

Citations

  1. Fenetylline: New results on pharmacology, metabolism and kinetics. OFDT — Drug and Alcohol Dependence article record (1986). https://bdoc.ofdt.fr/index.php?id=76491&lvl=notice_display1
  2. Captagon: Use and Trade in the Middle East. Human Psychopharmacology: Clinical and Experimental (2017). https://doi.org/10.1002/hup.254812
  3. Fenethylline (Captagon) Abuse – Local Problems from an Old Drug Become Universal. Basic & Clinical Pharmacology & Toxicology (2016). https://doi.org/10.1111/bcpt.12584123456
  4. Vaccine-driven pharmacodynamic dissection and mitigation of fenethylline psychoactivity. Nature (2017). https://doi.org/10.1038/nature234641
  5. Structural insight into the serotonin (5-HT) receptor family by molecular docking, molecular dynamics simulation and systems pharmacology analysis. Acta Pharmacologica Sinica (2019). https://doi.org/10.1038/s41401-019-0217-91
  6. Captagon trafficking and the role of Europe. European Monitoring Centre for Drugs and Drug Addiction (2023). https://www.euda.europa.eu/system/files/documents/2023-09/captagon-report_7september2023_final.pdf123
  7. Captagon trafficking and the role of Europe. European Monitoring Centre for Drugs and Drug Addiction (2023). https://bdoc.ofdt.fr/doc_num.php?explnum_id=343051
  8. The Captagon Threat: A Profile of Illicit Trade, Consumption, and Regional Realities. New Lines Institute for Strategy and Policy (2022). https://newlinesinstitute.org/wp-content/uploads/20220404-Captagon_Report-NLISAP-final-.pdf12
  9. Tackling the illicit drug trade fuelling Assad's war machine. Foreign, Commonwealth & Development Office (2023). https://www.gov.uk/government/news/tackling-the-illicit-drug-trade-fuelling-assads-war-machine1
  10. Capt. America vs Capt. Agon (The Billion-Dollar Bargaining Chip for the Syrian Republic of Captagon). Near East South Asia Center for Strategic Studies (2023). https://nesa-center.org/dev/wp-content/uploads/2023/06/2023-0602-CSAG-Info-Paper-Capt.-America-vs-Capt.-Agon-The-Billion-Dollar-Bargaining-Chip-for-the-Syrian-Republic-of-Captagon.pdf1

Further Reading

  1. “Chemical Courage”: Pharmacotoxicological Aspects of Fenethylline (Int. J. Forensic Sci. 2024)
  2. EMCDDA Captagon: understanding today's illicit market (2018)
  3. Insight of Captagon Abuse by Chemogenomics Knowledgebase (Scientific Reports 2019)
  4. Nervewing: blog - Captagon (Fenethylline) first-hand notes (2019-08-14)
  5. r/researchchemicals - Caffeine or Nicotine analogs? (user comments on Captagon dosing, 2022-07-06)
  6. The Emergence of the Old Drug Captagon as a New Illicit Drug: A Narrative Review (PMC 2024)
  7. The psychostimulant drug fenethylline (Captagon): Health risks review (Toxicology Advances 2025)

Article Status

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