UK Study Finds No Link Between Fluorinated Medicines and Reported Adverse Reactions
The analysis standardizing adverse-event reports by prescribing volume indicates reaction patterns reflect drug action rather than fluorine content.
Overview
- PLOS ONE published the University of Birmingham study on September 2, 2025, using 2019–2024 MHRA Yellow Card data with OpenPrescribing and NHSBSA dispensing records.
- Researchers compared 13 fluorinated medicines with six non‑ or low‑fluorinated comparators and calculated suspected adverse drug reactions per 1,000,000 items dispensed.
- On a per‑prescription basis, leflunomide showed the highest suspected ADR rate (343 per 1,000,000) while lansoprazole was lowest (14), even though both contain three fluorine atoms.
- No relationship was found between fluorine atom count and ADR frequency, with highly fluorinated drugs such as sitagliptin and flecainide not displaying elevated rates.
- Authors flagged limits from self‑reported surveillance that may undercount events and noted heightened scrutiny after PFAS reclassification that labels some medicines as containing “forever chemicals.”