Excretion of 4-fluoroamphetamine and three metabolites in urine after controlled oral ingestion

Stefan W. Toennes*, David Schneider, Werner Pogoda, Alexander Paulke, Cora Wunder, Eef L. Theunissen, Elizabeth B. de Sousa Fernandes Perna, Johannes G. Ramaekers

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review


Each year, synthetic drugs are occurring in high numbers in the illicit drug market. But data on their pharmacology and toxicology are scarcely available. Therefore, a pilot study was performed to evaluate excretion of 4-fluoroamphetamine (4FA) in humans and identify metabolites in urine.

Twelve subjects ingested 100 mg and five 150 mg 4-FA in a bitter lemon drink. Urine samples were scheduled at baseline and 4 times during the following 12 h and analyzed by liquid chromatography-mass spectrometry (LC-MSMS).

Concentrations of 4-FA were in the range of 0.7–38 mg/l which is in accordance with the data in previously reported cases. A marked decrease of creatinine excretion in the first two samples was noted. The creatinine normalized concentrations show a maximum 4 h after ingestion in accordance with serum pharmacokinetics. Three products of two metabolic pathways were identified in very low concentrations, two diastereomers of 4-fluorophenylpropanolamine and one ring hydroxylated 4-FA that was conjugated to a large extent. The concentration-time courses paralleled those of 4-FA.

The study results show the range of 4-FA concentrations to be expected in urine after oral ingestion of typical dosages and show two pathways of 4-FA metabolism.
Original languageEnglish
Article number113008
Number of pages8
JournalJournal of Pharmaceutical and Biomedical Analysis
Publication statusPublished - 3 Feb 2020


  • Pharmacokinetics
  • Stimulants
  • 4-Fluoroamphetamine
  • New psychoactive substances (NPS)
  • Liquid chromatography-mass spectrometry
  • Urine
  • Forensic toxicology

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