You have probably heard recently in the news about the new FDA alert regarding certain flea products. These are known as isooxazoline products which include Bravecto, Nexgard, Credelio and Simparica. These medications have proven to be very effective in controlling fleas and ticks on our pets. The FDA recently requested to have a change in the labeling of these medications to include risk of neurological issues. Signs of problems range from tremors, being off-balance to seizures in some dogs and cats. All of these products have been approved by the FDA.
At Town and Country Veterinary Hospital we carry and have recommended Nexgard for dogs as a monthly flea and tick preventative. For cats we do carry Bravecto Topical Solution as well as other flea and tick preventatives. It is best to review a pet’s medical history to determine whether a product in the isooxazoline class would be appropriate for your pet.
Nexgard has been on the market since January 2014. Over 200 million doses have been sold all over the world. We have learned from the manufacturer that there has been no increase in the reporting rate of adverse effects ever since it was introduced on the market in 2014. 1 in 10,000 pets may have an adverse effect. The most common adverse effect reported was vomiting, diarrhea and lethargy. Neurological adverse effects were significantly less. A warning on the Nexgard label has been in place since it was released regarding using caution with this medication in dogs with seizures. This had to do with the initial field study where 2 out of 3 dogs in the study that already had a history of seizures reported seizures while taking Nexgard. From reports we know that some dogs even with a history of seizures may not have seizures when taking Nexgard.
The most common adverse reactions recorded for Bravecto Topical Solution for cats in clinical trials were vomiting, itching, diarrhea, hair loss, decreased appetite, lethargy and scabs/ulcerated lesions. There is a label caution in cats with a history of neurologic abnormalities. Neurologic abnormalities have been reported even in cats without a history of neurologic abnormalities. (Merck Animal Health website: https://us.bravecto.com/for-cats)
Please let us know if your pet experiences any health problems while using an isooxazoline treatment. We also recommend reporting any adverse effects to the FDA as well as the pharmaceutical manufacturing company. Please see this fact sheet for pet owners from the FDA for more information: