How Dangerous Are Spot-On Flea & Tick Preventatives?

Spot-on flea and tick preventatives may be dangerous to your pet.

Gator received spot-on flea & tick preventatives for 10 years without incident. One night about 15 minutes after the application of Frontline® Plus for Dogs, the big Weimaraner began stumbling, falling against walls and furniture and shaking. This happened with no previous warning and lasted about 20 minutes.

We gave him 50 mg. of Benadryl as soon as the symptoms began and prepared for a trip to the emergency vet clinic. Slowly, the big dog settled down and relaxed. We quickly made the connection between the application of the spot-on product and Gator’s frightening, neurological symptoms.

Gator was one of many canines who, after years of using this particular spot-on product, suddenly developed a potentially fatal reaction to it. Some reactions include tremors, ataxia, vomiting, diarrhea, loss of appetite, and lethargy.

What Are Spot-On Flea & Tick Preventatives?

Spot-on flea & tick preventatives include several chemicals and come in liquid form. They are applied to the back of the dog’s or cat’s neck between the shoulder blades to kill the parasites.  The Food & Drug Administration (FDA) normally regulates animal drugs but in the case of external parasites, products may fall under the jurisdiction of the Environmental Protection Agency (EPA). In the case of these spot-on preventatives, the agencies work together to be sure manufacturers adhere to rules and regulations.

The Common Ingredient in Spot-On Flea & Tick Products

The common ingredient in so many of the products that have shown adverse reactions in canines is isoxazoline. It binds itself to the insides of fleas or ticks and paralyzes them. When a flea or tick attacks the blood in your dog’s body, the parasite eats that chemical and dies.

Creators of spot-on’s containing isoxazoline assume the animal won’t suffer any health issues, because the amount of the poison the dog absorbs is minute. But a dog treated once a month for years could experience build-up over time.

Guess what!  Every dog reacts differently. Some dogs will never experience a problem with the spot-on products. But others will struggle with minor to major health issues.

Thousands of Adverse Reactions Gets EPA’s Attention

Major news outlets reported on cases of neurological reactions in dogs and warned people about possible dangers. Beginning in 2009, the EPA (Environmental Protection Agency) began studying and testing popular spot-on products, collecting data from manufacturers and others. They studied active and inactive ingredients in the products and product labeling and collaborated with the FDA (Food & Drug Administration) to study data collected.

The EPA found that between 2007 and 2008, the number of adverse reactions to the spot-on drugs increased by 53%. In 2008, there were 43,000 reports of problems resulting from the use of the spot-on products. This clearly indicated problems with the products and warranted further study. The EPA also found that the data the agency requires does not accurately predict the toxicity seen in some of the study subjects.

Spot-On Product Labels Found Lacking. Here’s the Fix.

What they did find was that product labels failed to provide veterinary professionals and pet owners with adequate instructions to prevent misuse. One example of how they addressed that problem is the label now must repeat the words “dog” or “cat” and “only” throughout to avoid any misunderstanding about usage. Apparently, some pet owners had used the wrong product on their dogs or cats.

Warning! Using Spot-On Chemicals Meant for Dogs on Your Cat Could Kill

If the preventatives contain permethrin, they can only be given to dogs. Permethrin is toxic to cats.  Labels must clearly show which animal the product is intended for and the proper dosage per weight of said animal.

Choose Dependable & Safe Over Risky or Possibly Dangerous

Avoid spot-on flea and tick preventatives.Hundreds of products are sold to protect our dogs and cats from fleas and ticks. From powders, collars, sprays, shampoos, and pills, surely we can find a safe alternative to potentially dangerous spot-on products. so Natural solutions may also work.

My experience with our Weimaraner’s neurological episode from the use of Frontline® convinced me to not take chances with any future pets. Regular baths, a vet-recommended spray applied before Murphy visits the dog park, and brushing work well for him.

But if you believe that a spot-on flea and tick preventative works best for your dog, the EPA advises consumers to carefully follow the label directions and monitor your pet’s behavior and health after application for any signs of adverse reactions. Talk to your veterinarian about the pros and cons of the choice you make.




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