Bravecto/Nexgard are they safe?

The safety of the new Flea and Tick preventative products has been an active conversation on social media. We know how effective the new products are in preventing tick paralysis. In the face of the uncertainty about safety and the risks of tick paralysis, Veterinarian Dr. Helen Byrnes was asked to respond to a FB post suggesting a range of products were dangerous.In her response below Dr Helen explains why we continue to recommend these products.


Response from Veterinarian Dr. Helen Byrnes:

“Thanks for the opportunity to comment on the post. It’s very timely, given we are now in tick season! We recommend Bravecto and similar isoxazoline compounds because they are so effective in preventing death from tick paralysis. Your pet is much more likely to die from tick paralysis that to have an adverse reaction to an isoxazoline product. Our staff use these products for their own pets. We see many dogs and cats die from tick paralysis; we rarely see an adverse reaction to Bravecto or similar.

All products can cause adverse reactions in some patients, eg penicillin can cause severe reactions in some people. The isoxazoline products continue to be safe for most dogs. Product registration requires scientific evidence of both proven effectiveness and safety. The FDA registers the products in USA and the AVPMA in Australia.  There are no paralysis ticks in USA so they didn’t have to prove effectiveness for paralysis ticks.  But we did need those studies in Australia. Our experience has shown just how effective they are for paralysis ticks. 

The product insert on these products in Australia includes advice to avoid use in dogs who have seizures.  There’s recently been a flurry of social media activity because the FDA now requires a label warning on the box that the product may have adverse effects, rather than just providing the information in the product insert inside the box.  Staff in veterinary clinics receive good product training and advise clients with dogs who have seizures not to use these products. However people buying on-line and at pet stores, may not get that advice.  

We report any adverse reaction to any medication or other product that we use to the Australian regulatory authority (AVPMA). In the last few months, I reported one event when a dog was fed some fatty treats and also given Bravecto. That dog had had the fatty treat before, and separately a Bravecto before with no adverse reaction, but it seemed the combination wasn’t good. We also report adverse reactions to any prescription medication. 

By reporting adverse reactions, we build information about the rare effects of various medications and products. The most common adverse reaction to Bravecto we see is nausea or a gut upset. The gut upset seems to be worse if it is given with food that we don’t normally recommend for a dog such as a fatty meal. As worming tablets sometimes cause an upset tummy, don’t give a wormer at the same time as a Bravecto or Nexgard chew. We expect the new  spot-on Bravecto for dogs and cats to be gentler on the tummy.

Finally, remember that the risk of death from paralysis ticks is much greater the likelihood of an adverse reaction to Bravecto or similar product. We regularly see fatal cases of tick paralysis in dogs and cats that are not on any tick preventive product. Bravecto, Nexgard and Simparica have saved thousands of dogs’ lives.
Helen Byrnes”