By MEGAN TREMELLING
Nobody wants fleas and ticks on their dog. Even people who don’t like spending a lot extra on caring for their dogs don’t want those parasites getting into their homes and biting the humans. Therefore, valuing your dogs’ health and comfort and preventing external parasites is an important part of their overall care. Many people were worried to hear that the FDA had issued an alert in September about a potential danger associated with some flea and tick products that are part of the isoxazoline group: Nexgard (afoxolaner), Bravecto (fluralaner), Simparica (sarolaner) and Credelio (lotilaner).
What exactly is the problem? It seems that some dogs that have been treated with isoxazolines have developed neurologic symptoms, including tremors, ataxia (wobbly gait) and seizures. It is important to understand that millions of doses of these medications have been given to dogs, and that the fact that some dogs developed neurologic signs does not prove that the symptoms were always, or ever, caused by the medication. After all, some of those dogs probably broke a toenail after receiving the treatment, too. The reason this is different is that it is possible that in some cases the medication did cause the problem. We just don’t know enough to be sure. As with every new group of drugs, pre-release clinical studies can only teach us so much, and we learn much more when the medications are approved and used in large numbers of pets with a wide variety of concurrent medical conditions and medications on board. The FDA has more data on these medications than anyone else, and so far their official word is that “the isoxazoline class [is] safe and effective for dogs and cats.”
To get to a more complete understanding, veterinarians are researching possible adverse effects from isoxazolines and similar drugs, including neurologic changes and vision changes. In the meantime, for very young dogs and for dogs that have a history of seizures, tremors, ataxia, or vision loss, isoxazolines may not be the best choice. For dogs with no history of those problems, there is less reason to believe that these medications cause any significant danger.
As with so many things in life, all medical treatments come with risks and benefits. Veterinarians think in terms of minimizing risk because it is impossible to eliminate it. Isoxazolines have the advantage of being very convenient and very effective at killing fleas and ticks and, for most dogs, the benefits far outweigh the risks. I use one for my own dog.
Of course, if you are not comfortable using an isoxazoline for any reason, you should talk to your veterinarian about whether it is the right choice for your dog because many other options exist, with their own benefits and risks. If you think your dog may be having problems caused by an isoxazoline, you need to talk to your vet about that, too. It isn’t as simple as saying “it’s safer not to give the medication” because most of the time that just isn’t true. The benefits of flea/tick medications are enormous and very well documented; they reduce sickness and death from very common diseases that are transmitted by these parasites.
Stories like these sometimes cause people to reach for “natural” remedies in hopes that they will be safer. Unfortunately, they can be, in some cases, far more dangerous than carefully-tested and properly-prescribed medications. Herbal extracts and essential oils may have their uses, but flea and tick control is not among them. On the other hand, harmful effects, including death, are well-documented, especially when used incorrectly. Safety aside, I do not condone putting anything with a strong smell on your dog if you can help it. A dog’s nose is so sensitive that applying any strong smell to their bodies, where they cannot get away from it, is unlikely to be appreciated.
You may feel that your dog is at low risk for getting fleas and ticks, but if he ever sets paw on the ground or comes in contact with dogs that do, then he has the potential to be exposed to them no matter how meticulous your yard care. Never seen a flea or tick on him? You might not; they are pretty good at hiding. However your veterinarian can tell you whether you have a problem and help you find the solution that is right for your pet.