Underreporting of Adverse Drug Reactions in Veterinary Medicine

In the Literature

Davies H, Blackwell E, Fins IS, et al. Recording of suspected adverse drug reaction reporting in veterinary free‐text clinical narratives. J Small Anim Pract. 2024;65(6):361-367. doi:10.1111/jsap.13721

The Research …

Suspected adverse drug reactions (SADRs) are underreported in human medicine and are likely also underreported in veterinary medicine despite a lack of documentation.¹

In this study, text mining of veterinary records from general practice clinics in the United Kingdom was used to identify SADRs and determine whether they were reported to the Veterinary Medicines Directorate (VMD) or marketing authorization holder (MAH) to estimate the rate of underreporting. Adverse events are defined as unfavorable or unintended signs that occur after extra-label or label use of a veterinary medication, regardless of whether the observation is considered related to the product.

Text mining produced 10,565 records for manual review, and 827 records met criteria for SADRs. Approximately 90% of the SADRs were not recorded as reported to the VMD or MAH. Unexpected SADRs were more frequently reported than expected SADRs, but severity did not appear to impact whether a reaction was reported. The authors concluded improved systems for reporting are necessary to increase reporting of SADRs to support pharmacovigilance and improve drug safety.

… The Takeaways 

Key pearls to put into practice:

• Veterinary professionals and members of the public can report adverse reactions. In the United Kingdom, reports can be submitted to the VMD, or the MAH can be contacted. In the United States, SADRs can be reported to the FDA Center for Veterinary Medicine (CVM; see Suggested Reading); however, the FDA recommends submitting reports to the drug manufacturer, which is required to report drug reactions and product defects to the FDA.

• FDA CVM preapproval safety and efficacy studies are generally small in sample size, short in duration, and conducted in healthy animals or those that do not fully represent the target population of the drug, making postmarketing reports of SADRs critical for pharmacovigilance. In 1997, the FDA CVM received 4,000 adverse drug event reports; that number increased to >24,000 by 2001.² These reports identified several clinically important safety risks, including blindness associated with high doses of enrofloxacin in cats, overdose of moxidectin in horses associated with failure of a syringe-locking device, and keratoconjunctivitis sicca associated with use of etodolac in dogs.

• SADRs should be reported for FDA-approved products, unapproved drugs, indexed or conditionally approved drugs, devices, and compounded drugs per FDA Guidance for Industry #256. Resources and instructions for reporting are available (see Suggested Reading).