You may have recently read or heard about an FDA alert regarding flea and tick prevention products in the isoxazoline class.  This class includes products such as Bravecto, Nexgard, Simparica, and Credelio.  Understandably, we’re sure you’d like to know exactly what this alert means for you and your beloved pets.

As with all human and animal medications, side effects or adverse events are possible and are listed on the product inserts and packaging of medications. Although FDA scientists carefully evaluate an animal drug prior to approval, new information may be noted after the product has been marketed and used by a much larger population. The FDA pays close attention to adverse event reports, especially in the first few years after approval, to find any new safety concerns that may emerge.

In the case of the flea and tick products listed above, post-marketing data has indicated that some animals receiving these medications have experienced adverse events such as muscle tremors, ataxia (uncoordinated walking), and seizures.

The FDA issued this alert to make pet owners and veterinarians aware of these events and to inform us that they are currently working with the manufacturers to include new label information to highlight these neurological events.

It is important to note that in this alert, the FDA also states the following:

“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.”

At Companion Animal Hospital of Wakefield, we understand the possibility of adverse events with all medications including flea and tick preventions. We measure these risks to the benefit of flea and tick-borne disease prevention and will continue to make recommendations with your pets’ individual health needs in mind.

To date, we have not experienced the discussed adverse events in our patients or personal pets to the products listed above. We urge you, however, to please alert us to these or any other adverse events that you may encounter with any products we dispense.

While we feel these products are safe for continued use, we also want you to be comfortable with the products your pet receives. We urge you to visit the FDA website listed below to read the alert for yourself. We also welcome you to call so that we can answer any additional questions you may have or guide your selection for alternative products should you elect to change.



Companion Animal Hospital of Wakefield


FDA direct link: