There’s a new warning from the Food and Drug Administration (FDA) about the newer class of flea and tick medications (Bravecto, Nexgard, Credelio and Simparica).
Just a few months ago, I posted about these medications. Due to the new FDA warning released on September 20, 2018, I believe I was too positive about these drugs on Petful, and I want to update you on this latest warning.
These 4 meds mentioned above are similar products, called the isoxazolines, currently made by 4 different veterinary pharmaceutical companies — so far.
Once a new kind of flea/tick or heartworm medication is developed, every veterinary pharmaceutical company tries to get on board as soon as they can and get their own product out on the market to make as much of a financial killing as possible before their patent runs out.
That’s why products like Advantage used to be by prescription only. Now you can find it anywhere.
Here’s what seems relevant right now:
- The updated FDA’s warning is all about possible neurologic reactions related to these drugs. These include muscle tremors, ataxia (lack of balance) and seizures: “The United States FDA is alerting pet owners and veterinarians to be aware of the potential for neurologic adverse events in dogs and cats when treated with drugs that are in the isoxazoline class.”
- More reactions have been reported: “The FDA is working with manufacturers of isoxazaline products to include new label information to highlight neurologic events because these events were seen consistently across the isoxazoline class of products.”
Why This Is Relevant
- The FDA does not issue many warnings on veterinary drugs. Any warning means that vets should reconsider the safety of the drug and prescribing that drug should carry more thinking and discussion with clients.
- These products still need a prescription from a veterinarian. The onus is on us vets to make sure we have a long-enough discussion with you, the pet lover, about your animal’s medical history and conditions to decide if these products are safe and appropriate to use.
- These products should not be prescribed to any animal with any neurologic condition whatsoever.
- If your pet has ever had a seizure or a neurologic event, you should not use these drugs.
- If you use any of these products and your pet has any reaction whatsoever, don’t use them again.
Drug Reactions Are Underreported
Some people freak at even a tiny muscle twinge or vomit after they give their pet a drug, but many folks take a drug reaction in stride and don’t call their vet or the drug manufacturer. The reaction goes unreported.
There are many more reactions to these drugs than the FDA knows about. The number reported, however, was still enough for it to issue this additional warning.
An anesthesiologist was talking about using Nexgard. She said, “Oh, it works great, but my dog had a little seizure after I gave it.”
Now, because she’s a human anesthesiologist, the “little seizure” didn’t freak her out. To a pet lover without a medical background and experience observing seizures , however, this episode could have been highly disturbing.
Though this was not good for the dog, this fairly major reaction went unreported.
Nexgard was on the market for about a year; it seemed effective and safe. There weren’t a lot of reports about adverse reactions.
My 13-year-old Cocker Spaniel — with a mild epileptic seizure disorder for his entire life (puppy mill rescue) — hated topical stuff put on him. I used Nexgard without any problem whatsoever.
Heeding these warnings now, however, he should never have been given Nexgard. He was lucky that I, his loving human and veterinarian, did not make his seizure disorder worse by giving him this drug.
September is a bad time for fleas. The FDA issued this warning in a very timely fashion. More people might be looking to use a highly effective flea treatment at this time of year.
Hot and humid climates have flea issues all year round, but even some of my friends in Florida stop using flea meds in the winter and begin in summer to fall.
In colder climates — like the Northeast, where I practice — many clients believe they “have never had a flea,” but lo and behold, the little critters have been subletting an apartment on their dog’s body for July and August, and September is the time when they get a letter from rent control.
“Time’s up. You are a flea bag. We need you out of this apartment. Now!”
So you go out and try to find a highly effective flea treatment, possibly from your vet. You might come home with Nexgard, Bravecto, Credelio or Simparica.
Here’s a little more info on the FDA’s recent warning:
Vigilance Is Key
These medications are considered safe and very effective for the general pet population.
On a busy day in my hospital, however, when a “good” client comes in for flea and tick medications and we suggest Nexgard, did we do due diligence in asking them all the appropriate questions?
Given this new FDA warning, I can say no, not always.
In the future, before I prescribe Brevecto, Nexgard, Credelio or Simparica, there should be an in-depth discussion about the pet’s health status, any neurologic episodes or conditions that might have gone undocumented, and a careful discussion about the pros and cons of these products.
That being said, in a few years, if these drugs are sold over the counter, you won’t have the benefit of talking to anyone but a pet store or Target employee.
This pet health content was written by a veterinarian, Dr. Debora Lichtenberg, VMD. It was last reviewed Oct. 10, 2018.