Veterinarians caution pet owners about OTC flea and tick products

Photo (c) Tatomm - Getty Images

Some contain chemicals that can harm dogs and cats

Pet owners understandably go to great lengths to protect the health of their dog or cat and part of that vigilance is preventing fleas and ticks which can carry a disease from infecting their furry friends.

While prescription products are generally safer and better tolerated, consumers have a wide range of choices in over-the-counter (OTC) flea and tick products that can be purchased online or at retail stores. Some can produce severe physical reactions in pets, as Sasha, of Bristol, R.I., discovered when she administered OTC flea and tick drops to her cat.

“Right after I put the drops on him he went NUTS,” Sasha wrote in a ConsumerAffairs review. “He started having severe spasms, he was TERRIFIED, screaming, crying, sprinting around, and hiding. It was the most traumatic experience I've ever seen an animal go through.”

Sasha’s story has a happy ending. She took the cat to an emergency vet facility where he was treated and recovered. But there have been instances where pets that were administered OTC flea and tick products have died.

Chemicals that target insects can affect some animals

A pet owner might ask why these products continue to be sold. It was a question we put to a couple of animal health experts.

Amber LaRock, a licensed veterinary technician and Vet Pro with Vetted Pet Health, says certain ingredients designed to kill insects can adversely affect a small percentage of animals, in particular dogs. But it’s only a small percentage, just as many prescription drugs for humans can produce very serious side effects in a small percentage of people.

“The ingredient responsible for many of the adverse reactions to flea and tick products in dogs is isoxazoline,” LaRock told ConsumerAffairs. “This ingredient is found in most popular flea and tick prevention products, and it can lead to neurological symptoms in a small percentage of canine friends. If a dog does have a sensitivity to this ingredient, they will often experience lethargy, muscle tremors, a wobbly gait, and seizures in some cases.”

The District of Columbia Attorney General’s Office recently warned pet owners about flea and tick products containing Tetrachlorvinphos (TCVP). The chemical is commonly used in pet products to kill fleas and ticks. 

“TCVP kills these pests, but also may be extremely dangerous for pets and their owners, especially young children, and pregnant women,” the attorney general’s office said in a release. “Thousands of pets have been harmed by this pesticide. And, even small amounts of exposure can cause irreversible harm to a child’s brain development and increase the risk of learning disabilities.”

The attorney general’s office offered this list of OTC products it says contain TCVP or other potentially harmful chemicals:

  • Hartz Ultra Guard Flea and Tick Collar

  • Pet Armor Flea & Tick Collar

  • Zodiac Flea and Tick Collar

  • Adams Plus Flea & Tick Collar

  • Hartz Ultra Guard Flea and Tick Powder

  • Hartz Ultra Guard Flea and Tick Spray

  • Bio Spot Flea and Tick Collar

  • Seresto Flea and Tick Collar

Other options

LaRock says TCVP is mostly used in OTC flea and tick collars. She says there are better options.

“Veterinary-prescribed oral and topical products will not contain this ingredient, so it would be best to skip the store flea collars and go the prescription route,” she said.

Louis DelGiudice, national emergency specialty director for AmeriVet Veterinary Partners, says pet owners should consult with their vet about any OTC product for their dog or cat because there may be better and safer alternatives.

“I also advise owners to not purchase over-the-counter products from large retail stores,” DelGiudice told us. “Purchase from your veterinarian or a pharmacy. The flea and tick preventatives that are obtained this way with a prescription, the companies are reputable and will investigate reports working the veterinarian and owner, regarding concerns with their products.”

Aging-in-place? Find a modern medical alert system to ensure help is always near.