By Samantha Bartlett

Librela, a monoclonal antibody used for treatment of osteoarthritis pain in dogs, was approved by the FDA in May 2023. The drug, developed by Zoetis, is administered as a monthly injection by veterinarians only. Since its arrival on the market, approximately 3600 reports of adverse events were received in the first year. These events included neurological signs such as ataxia, seizures, paralysis, anorexia, lethargy and recumbency, urinary incontinence, polyuria and polydipsia, vomiting, diarrhea, muscle tremors, lameness, and death or euthanasia. These reports can be accessed online through the FOIA Electronic Reading Room. 

These reports prompted the FDA to initiate an investigation resulting in a “Dear Veterinarian” letter issued earlier this year. In its investigation, the FDA discovered that approximately 2/3 of the adverse events occurred within a week of receiving the injection with 30% occurring on the first day of the injection. 70% of these events occurred with the initial dose of Librela and about 30% of the events involved no other medications or supplements.

The FDA is encouraging veterinarians to continue to report any adverse events that may be associated with administration of Librela. Veterinarians can report directly to Zoetis at 1-888-963-8471 or to the FDA via its online reporting system. 

FDA Online Reporting System: https://www.fda.gov/animal-veterinary/report-problem/how-report-animal-drug-and-device-side-effects-and-product-problems

Dear Veterinarian Letter: https://www.fda.gov/animal-veterinary/product-safety-information/dear-veterinarian-letter-notifying-veterinarians-about-adverse-events-reported-dogs-treated-librela

FOIA Electronic Reading Room: https://www.fda.gov/about-fda/center-veterinary-medicine/cvm-foia-electronic-reading-room