Overview

• Published in PLOS ONE on September 2, 2025, the University of Birmingham study examined suspected adverse drug reactions using UK data from 2019 to 2024.
• MHRA Yellow Card reports were paired with OpenPrescribing and NHSBSA dispensing records to calculate adverse reactions per 1,000,000 items for selected system organ classes.
• No overall correlation emerged between the presence or number of fluorine atoms in a medicine and reported adverse reactions, with highly fluorinated drugs like sitagliptin and flecainide not showing the highest rates.
• Safety profiles varied by drug, as leflunomide recorded the highest rate at 343 suspected reactions per 1,000,000 items, while lansoprazole had the lowest at about 14 despite similar fluorination features.
• Signals reached statistical significance across five system organ classes after excluding congenital, familial, genetic, and endocrine disorders, though the authors caution that self-reported Yellow Card data may underreport events and the findings do not address environmental PFAS risks.