FDA alerts veterinarians, pet owners about neurologic risks associated with isoxazolines

The FDA is warning veterinarians and pet owners to be aware of the potential for neurologic adverse events in dogs and cats treated with drugs in the isoxazoline class, according to an agency release.

Since these products have obtained their respective FDA approvals, data received by the agency indicates that some animals receiving fluralaner (Bravecto-Merck), afoxolaner (Nexgard-Merial/Boehringer Ingelheim) or sarolaner (Simparica-Zoetis) have experienced adverse events such as muscle tremors, ataxia and seizures, the release states. Another product in the isoxazoline class, lotilaner (Credelio-Elanco), recently received FDA approval. These products are approved for the treatment and prevention of flea infestations and the treatment and control of tick infestations.

The FDA says it is working with manufacturers of isoxazoline products to include new label information to highlight neurologic events because these events were seen consistently across the isoxazoline class of products.

The agency says it carefully reviewed studies on Bravecto, Credelio, Nexgard and Simparica before approval, and these products continue to be safe and effective for the majority of animals. The agency is asking the manufacturers to change product labeling to help veterinarians and pet owners make treatment decisions for each pet on an individual basis. Veterinarians should use their specialized training to review their patients' medical histories and determine, in consultation with pet owners, whether a product in the isoxazoline class is appropriate for the pet, the release states.