WARNING! The Truth About Flea and Tick Medications - Rescue Dogs 101

WARNING! The Truth About Flea and Tick Medications

The Facts of Life with a Dog: Fleas and Ticks

Flea and ticks are pests I think we all can all agree we can do without, they’re creepy, crawly and they spread diseases. Unfortunately, insects are part of our lives, and chances are you’ve seen a flea or tick in your lifetime, especially if you have a dog. Have you ever wondered what the best flea and tick prevention is for your dog?

If you live in a city environment, maybe fleas and ticks aren’t as prevalent. But we currently live a suburban area and take our dogs to the dog park, camping and hiking all the time. Plus, we are moving soon to a rural area that I know will be tick infested.

WARNING! The Truth About Flea and Tick Medications

UPDATE: 9/20/18 from the FDA: Animal Drug Safety Communication: FDA Alerts Pet Owners and Veterinarians About Potential for Neurologic Adverse Events Associated with Certain Flea and Tick Products

On the list of products the FDA is warning us about are Bravecto, Credelio, Nexgard and Simparica. Some pets have experienced adverse events such as muscle tremors, ataxia, and seizures.

No one wants to find a tick on their dog, so we listen to our vet and purchase the flea and tick products based on their recommendations. Frontline Plus, K9 Advantix II, NexGard, Seresto are all commonly available from your vet, online or in the pet stores.

Deciding whether to give your dog a flea and tick pill, collar or topical solution isn’t the only things to consider. Finding the best flea and tick prevention is going to take a little detective work. To help you, I’ve done all the research below:

How Do Flea and Tick Products Work?

Did you know the active ingredients in all of these products are pesticides? Yes, you read that correct, you are putting poison on your dog! Yikes, scary right?
How can these companies get away with marketing a poison to pet owners? They all say the amount is slow-releasing in small amounts and are perfectly safe for your dog. Really? Would you put pesticides on yourself or your kids? Nope, didn’t think so.

warning pesticide sign dogs

We’ve used both Frontline Plus and K9 Advantix on our dogs. I’m embarrassed to admit, I never looked at the back of the boxes until last year. After reading something online, I started researching and it didn’t take long for me to realize this stuff is slowly killing our dogs.

Even the Humane Society of the United States warns us about the use of these chemicals on our dogs! “Before you use any of these products on your pets, it is critical to read their labels and consult with your veterinarian. They may contain ingredients that could harm pets and people.”

What Are the Active Ingredients in Flea and Tick Products?

I’ve researched each of the top-selling flea and tick products. Found their active ingredient list from their website and put it all together here for you to make your own informed decision.

Scary fact: I found all the ingredients listed on these flea and tick medications on the National Pesticide Information Center.Click To Tweet National Pesticide Information Center

Frontline Plus


Ingredients: Fipronil, (S)-methoprene

Fipronil is a broad use insecticide that belongs to the phenylpyrazole chemical family. Fipronil is white powder with a moldy odor, used to control ants, beetles, cockroaches, fleas, ticks, termites, mole crickets, thrips, rootworms, weevils, and other insects.

Methoprene is used against insects. It comes in two different forms called s-methoprene and r-methoprene, and s-methoprene is the one that behaves like an important hormone in insects. It can be used against fleas, flies, moths, beetles, and other insects.

K9 Advantix II


Ingredients: Imidacloprid, Permethrin, Pyriproxyfen

Imidacloprid is an insecticide that was made to mimic nicotine. Nicotine is naturally found in many plants, including tobacco, and is toxic to insects. Imidacloprid is used to control sucking insects, termites, some soil insects, and fleas on pets.

Permethrin is an insecticide in the pyrethroid family. Pyrethroids are synthetic chemicals that act like natural extracts from the chrysanthemum flower. Permethrin is used in a number of ways to control insects. Products containing permethrin may be used in public health mosquito control programs. They may be used on food and feed crops, on ornamental lawns, on livestock and pets, in structures and buildings, and on clothing. Permethrin may also be used in places where food is handled, such as restaurants.

Pyriproxyfen mimics a natural hormone in insects and disrupts their growth. It is a type of insect growth regulator that affects mostly young insects and eggs. Pyriproxyfen affects many types of insects, including fleas, cockroaches, ticks, ants, carpet beetles, and mosquitoes.



Ingredients: Afoxolaner has the chemical composition 1-Naphthalenecarboxamide, 4-[5- [3-chloro-5-(trifluoromethyl)-phenyl]-4, 5-dihydro-5-(trifluoromethyl)-3-isoxazolyl]-N-[2-oxo-2-[(2,2,2-trifluoroethyl)amino]ethyl.

From what I can tell Afoxolaner was created specifically for use in NexGard? So that is why they have the breakdown of what the composition of the chemicals is, the only chemical I could find is Naphthalene carboxamide.

Naphthalene is an aromatic hydrocarbon found in coal car or crude oil. Naphthalene is used in the manufacture of plastics, resins, fuels, and dyes. It is also used as a fumigant insecticide that works by turning directly from a solid into a toxic vapor. This process is called sublimation. Most products containing naphthalene in the U.S. are used to control clothes moths in airtight containers.



Ingredients: Imidacloprid, Flumethrin

Imidacloprid is an insecticide that was made to mimic nicotine. Nicotine is naturally found in many plants, including tobacco, and is toxic to insects. Imidacloprid is used to control sucking insects, termites, some soil insects, and fleas on pets.

There it is in black and white, each one of these popular flea and tick products that are recommended to use on our dogs contains insecticides. Do you still feel it’s okay to protect your dog with these chemicals?

If you are wondering if heartworm preventative is safe, same rules apply. Check out The Truth About Heartworms By Only Natural Pet.

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Side Effects of Flea and Tick Products

  • Vomiting
  • Diarrhea
  • Lethargy
  • Weakness
  • Staggering
  • Disorientation
  • Hypothermia
  • Abdominal pain
  • Light or severe depression
  • Allergic reactions, such as rashes and itching

I found this great comprehensive resource that explains a lot of the flea and tick products and chemicals, along with natural options: GreenPaws Flea and Tick Products Directory.

Is It Possible to Protect Your Dog from Fleas and Ticks with Natural Ingredients?

I will admit, I’m scared to NOT protect my dogs from fleas and ticks. Our foster dog, Taylor had Lyme disease, which is contracted from being bit by an infected tick. And now that we will be living in a rural area that is known to have ticks, I need to make sure I protect my dogs and family.

So I began searching for natural flea and tick prevention for our dogs. From homemade flea and tick prevention with essential oils to natural products available to purchase online.

I’ve ordered several options and will be testing on our dogs to see what works best over the next few months. I will make sure to report back with my findings. Until then, follow me on Facebook to see updates throughout the summer.

So What is the Best Flea and Tick Prevention Solution?

Should you continue using Frontline Plus or K9 Advantix? You aren’t a bad dog parent if you decide to use these products, we all need to make our own decisions and do what is best for our dogs. No judgement from me. But now that you know the facts, I’d love to hear what you decide to use to protect your dog from fleas and ticks. Will you continue to use the pesticide products, or try something natural?

Please comment below with what works for you and your dog, it will help others in the Rescue Dogs 101 community to make an informed decision.

Recommended just for you:

Are Flea and Tick Medication Safe for My Dog?

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About the Author Debi@RescueDogs101

Debi McKee is a dog mom, volunteer foster dog home, and lifetime dog lover. Debi’s mission is to guide you through every step of your dog journey, from adopting the perfect dog for you and your family, to training your dog and keeping your dog happy and healthy. Sign up for our free resource library of must-have resources, containing valuable downloads to help you in your dog journey.

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