The agency recommended that the maker of Librela update its label to reflect the possibility of more serious adverse reactions.
A popular drug for dogs with arthritis may be associated with a variety of potentially severe neurological effects, including seizures and a loss of muscle control, according to a recent review by the U.S. Food and Drug Administration, which approved the drug last year. In some cases, dogs have died or have been euthanized after developing these symptoms, the agency noted.
The drug, called Librela, is an injection of monoclonal antibodies that is approved for arthritis-related pain in dogs. Its label lists mostly mild side effects, such as urinary tract and skin infections.
But since the drug became widely available, some pet owners have reported that their dogs became seriously ill, lost the ability to walk or stand or even died shortly after receiving the drug.
The F.D.A.’s analysis, which is based on more than 3,600 adverse-event reports submitted to the agency and the drug manufacturer, does not prove that Librela caused these problems or estimate how frequently they might occur.
But such reviews can help regulators identify potential side effects that smaller clinical trials may have missed. The F.D.A. has alerted veterinarians to the adverse events that may be associated with Librela and recommended that the drug’s label be updated to include them.
Zoetis, the company that makes Librela, said that more than 21 million doses of the drug had been distributed globally and that side effects were rare. “We at Zoetis — and I personally — stand 100 percent behind Librela as safe and effective,” said Dr. Richard Goldstein, the company’s chief medical officer.