FDA Issues Advisory for Newer Oral Flea and Tick Medications

adverse neurological effects have been reported since these drugs gained FDA approval

FDA Issues Advisory for Newer Oral Flea and Tick Medications
Image: Pixabay
October 1, 2018

Thinking of going to an oral flea medication for your pet? You might want to wait. The U.S. Food and Drug Administration is alerting pet owners and veterinarians to be aware of the potential for adverse neurological effects in dogs and cats when treated with drugs that are in the isoxazoline class, which include Bravecto, Nexgard, Simparica and Credelio. These products are approved for the treatment and prevention of flea infestations, and the treatment and control of tick infestations.

adverse reactions have been reported

Since these products have obtained their respective FDA approvals, data received by the FDA as part of its routine post-marketing activities indicates that some animals receiving Bravecto, Nexgard or Simparica have experienced adverse events such as muscle tremors, ataxia, and seizures. Credelio only recently received FDA approval.

The FDA 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. In other words, it wasn't isolated to one particular medication.

Safe for majority of animals

The FDA carefully reviewed studies and other data on Bravecto, Credelio, Nexgard and Simparica prior to approval, and these products continue to be safe and effective for the majority of animals. The agency is asking the manufacturers to make the changes to the product labeling in order to provide veterinarians and pet owners with the information they need to 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.

New information often emerges after FDA approval

Although FDA scientists carefully evaluate an animal drug prior to approval, there is the potential for new information to emerge after marketing, when the product is used in a much larger population. In the first three years after approval, the FDA pays particularly close attention to adverse event reports, looking for any safety information that may emerge.

The FDA monitors adverse drug event reports received from the public or veterinarians, other publicly available information (such a peer-reviewed scientific articles), and mandatory reports from the animal drug sponsor (the company that owns the right to market the drug). Drug sponsors must report serious, unexpected adverse events within 15 days of the event. In addition, they must submit any events that are non-serious, plus any laboratory studies, in vitro studies, and clinical trials that have not been previously submitted to the agency, on a bi-annual basis for the first two years following product approval and annually thereafter.

Report adverse reactions to the FDA

The FDA continues to monitor adverse drug event reports for these products and encourages pet owners and veterinarians to report adverse drug events directly to the FDA.