Can Fleas Cause Dogs to Have Seizures

Posted by Max Martinson on

can fleas cause seizures?

Parasitic infections are a common occurrence in dogs. The most notorious are fleas and ticks. These tiny insects can cause unbearable discomfort to our beloved canines. Some common symptoms of infestation include skin allergies, itching, and anemia.

But one question worth exploring is whether ticks and fleas cause seizures in dogs. Let's uncover the truth below and what you can do about it.

Do Ticks and Fleas Really Cause Seizures?

During heavy tick and flea infestations, dogs may experience seizures. For dog owners, it can be disheartening to see your beloved pet suffer. The condition manifests in convulsions, altered behavior, and uncontrolled movements. And, in some instances, your dog may lose consciousness. That establishes a connection between the parasites and the medical condition.

Well, there is no scientific evidence to show that ticks and fleas cause seizures. Many studies show that the culprit could be flea and tick products. The American Veterinary Medical Association (AVMA) narrows it to isoxazoline class drugs. They go further to name three specific products: Bravecto, Simparica, and Nexgard. 

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How to Minimize Unexpected Side Effects

The FDA is emphatic about getting a go-ahead from the vet before using any tick and flea products. This is especially critical if the ingredient list includes isoxazoline. The vet will look at your dog's medical history. They will also consider any underlying or pre-existing issues before prescribing the products.

Also, please avoid using the tick and flea products under specific conditions. Such include pregnant or nursing dogs and those with allergies. Specific medications can cause drug interactions that could harm your canine.

Like with any other medication, please stick to the dosage recommendation. The vet will share such information during your visit. You could also check the manufacturer's label for further instructions.

Are Some Dogs More Vulnerable?

Yes, some canines will be more vulnerable to the side effects of tick and flea products. Top of the list are those with underlying health conditions. Such include neurological conditions or sensitivities.

The age of the dog also matters. Very young pups and senior dogs have weaker immune systems. Thus, their tolerance for the medications will be much lower.

Genetics also play a role in vulnerability. Some dog breeds have predispositions to particular sensitivities and health conditions. They may, for instance, have sensitivities to specific active ingredients. Other dogs are at higher risk due to allergic reactions to particular chemicals in the flea and tick products. 

You may also heighten the vulnerability. This happens due to cumulative exposure or extensive use of many tick and flea products.

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Frequently Asked Questions

The following answers were generated and reviewed by the Lolahemp team.

What Is the Effect of Isoxazoline?

Isoxazoline is a class of compounds commonly found in flea and tick products. These products are formulated to provide safe and effective prevention of flea and tick infestations in dogs and cats. Isoxazoline works by targeting the nervous systems of fleas and ticks, leading to paralysis and eventually their death. While isoxazoline-based products have been beneficial in controlling these pests, it's essential to be aware of potential adverse effects.

What Does the FDA Say About Flea and Tick Products?

The FDA plays a crucial role in evaluating the safety and effectiveness of flea and tick products. While these products have proven to be effective in many cases, the FDA acknowledges the potential for adverse events. Some animals may experience neurologic adverse reactions, including muscle tremors and ataxia, after using flea and tick preventives. Pet owners should be aware of these risks and consult their veterinarian before use.

Why Are Seizures a Common Side Effect of Flea and Tick Medications?

Seizures can occur as a potential side effect of some flea and tick medications, particularly those containing isoxazoline. While these medications are generally safe, some animals, especially those with a prior history of seizures or underlying health problems, may be more susceptible to adverse reactions. Pet owners should be cautious and discuss their pet's medical history with a veterinarian before administering these products.

Do the Benefits of Flea and Tick Medications Outweigh the Cons?

Balancing the benefits and potential risks of flea and tick medications is a crucial consideration for pet owners. Flea and tick infestations can lead to various health issues for pets and even humans. While adverse events are relatively rare, pet owners should weigh the benefits of preventing these infestations against the potential for adverse reactions. Consulting with a veterinarian can help make an informed decision.

Are There Best Practices for Keeping Your Dog Safe?

To ensure the safety of your pets when using flea and tick medications, it's important to follow best practices. First, consult your veterinarian before starting any preventive treatment. Provide your vet with information about your pet's medical history, including any history of seizures. If your pet experiences any unusual symptoms, such as seizures, muscle tremors, or ataxia, after administering the medication, seek veterinary attention immediately.


We have answered the question, can fleas cause seizures in dogs with a no. What we need to be asking is can flea medicine cause seizures in dogs, and the answer is yes.

Flea and tick products containing isoxazoline-class drugs have been associated with seizures. Despite their FDA approval, numerous reports of adverse reactions in canines have been documented. It is advisable to consult your veterinarian before using any tick and flea products on your beloved canine.




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Max is the Content Director for Lolahemp. He works closely with Lolahemp's veterinarians and writers, ensuring that our articles are factual, enjoyable, and useful to pet owners. Before Lolahemp, Max contributed articles to various pet health and wellness sites around the internet after graduating from the University of Wisconsin, Eau Claire. He is also the proud owner of a mischievous grey cat named Herbie.
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