Most adverse drug reactions unreported, study finds
The researchers also want regulators to make reporting quicker and easier.
Veterinary professionals are being encouraged to report suspected adverse drug reactions, after a new study found that the vast majority were not reported.
Researchers from the University of Liverpool reviewed more than 10,000 electronic health records from the Small Animal Veterinary Surveillance Network (SAVSNET). They found 827 cases of suspected adverse drug reactions, of which around 90 per cent went unreported.
Heather Davies, lead author of the study, explained: “It has long been thought that adverse drug reactions are under-reported. This work used real world evidence from first opinion practice to be the first publication that confirms this suspicion.”
Free-text clinical narratives of consultations stored in SAVSNET were screened for the phrases ‘adverse drug reaction’ and ‘side effect’.
The researchers then analysed the records to determine the seriousness and expectedness of the reaction, the suspected product, and whether it had been reported to the Veterinary Medicines Directorate (VMD) or the relevant marketing authorisation holder.
Most of the cases involved dogs and 70 per cent were listed as ‘expected’. Reactions which were not expected were more likely to be reported. The study also found that there was no correlation between the clinical severity of the reaction and how likely to was to be reported.
Dr Davies added: “As adverse drug reaction reporting rate is directly linked to the regulator's ability to mitigate safety issues, this paper is a call to arms encouraging all veterinary professionals to report suspected adverse drug reactions and regulators to make reporting quicker and easier.
“It also the highlights the promise that big real-world data sets hold in enhancing drug safety monitoring processes.”
The study, which received funding from BSAVA PetSavers and the VMD, has been published in the Journal of Small Animal Practice.
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The BSAVA has opened submissions for the BSAVA Clinical Research Abstracts 2026.
