Majority of suspected adverse drug reactions in veterinary medicine are unreported, study shows

16 April 2024

Whilst it has long been suspected that adverse drug reactions are under-reported in the veterinary profession, a new study is the first to reveal the scale of under-reporting in small animal general practice, using real data from veterinary clinical records.

The study, published in the Journal of Small Animal Practice, searched electronic health records within the Small Animal Veterinary Surveillance Network (SAVSNET), to identify instances of suspected adverse drug reactions (sADRs). Records were searched using two regular expressions to identify mentions of “adverse drug reactions” and “side effects” in the free-text clinical narratives, and these were then analysed to determine the suspected product, the seriousness and expectedness of the event, and whether the event had been reported to the Veterinary Medicines Directorate or Marketing Authorisation Holders.

Of the 827 cases of suspected adverse drug reactions identified out of a total of 10,565 records reviewed, the vast majority (approximately 90%) were not reported. Most of these sADRs (74%) were related to dogs and the majority (70%) of sADRs were listed as “expected” (i.e. already listed in the product information). The clinical severity of the reaction didn’t appear to impact whether it was reported.

Reporting of adverse drug reactions is vital for monitoring the safety and efficacy of medicines, and a lack of reporting might delay detection of drug safety concerns and subsequent mitigation. Veterinary professionals are encouraged to report adverse events by the RCVS Code of Professional Conduct but are under no legal obligation to do so.

Dr Heather Davies, lead author of the study, said: “’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. As adverse drug reaction reporting rate is directly linked to the regulators 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.”

Professor David Killick, senior author of the study, said: “We would like to extend our thanks to BSAVA PetSavers and the Veterinary Medicines Directorate for funding this research and to the veterinary practices who participate in the SAVSNET project without whom this research would not be possible”.

Access the full study here:

The study was part funded by BSAVA PetSavers, the grant awarding arm of the British Small Animal Veterinary Association. It is funded solely by charitable donations and has invested more than £2 million in vital clinical research and training programmes over the past 40 years to advance clinical investigations into pet animal medicine and surgery. For further information visit:

Find out more about the Investigating the reporting of adverse drug reactions using electronic healthcare records study.

Companion article on the adverse drug reactions study

Companion article on wider research by SAVSNET, including the drug safety research