SWFL dog owner says possible serious side effects from flea/tick medication

A Southwest Florida pet owner has a warning for others about possible side effects from a popular flea and tick medication. The local dog owner says people’s dogs could end up with lost mobility and limping.

We also spoke to a veterinarian about the commonality of these side effects.

Pet owner Joe Brewster says his dog, 12-year-old Buddha, is getting around a little slower these days.

“She gets tired,” Brewster said. “She had a better walk; she walked a little bit farther because she wants to do it.”

Brewster believes it’s not from her old age. He said Buddha had a seizure and then lost mobility in her back legs. So he took her to the vet and a neurologist.

“They asked me if I changed flea and tick medication,” Brewster said. “And I thought for a minute, and I go, ‘Yeah, three days before.’”

Brewster told us, days before Buddha’s episode, he treated her with PetArmor Plus for Dogs.

“As far as a normal, healthy dog, there is no research to suggest that it causes neurological activity,” said Dr. Wendy Mandese, a veterinarian and a professor at UF.

Mandese explained side effects like Buddha’s are rare.

“We may see an animal that has an issue one or two times a year,” Mandese said. “It’s very uncommon. I would say the diseases we see that are caused from a disease carried by fleas and ticks is much more common than side effects you may see from the product itself.”

The EPA told us the agency received more than 1,300 reports of “unreasonable adverse side effects” from PetArmor since 2011. The EPA terms that as “very small” compared to the volume of PetArmor Plus sold annually.

We asked the makers of PetArmor Plus to respond to Brewster’s claim, but we have not received a response.

Brewster said, at the very least, the package should warn users there is a risk of seizure.

“This isn’t right. This is animal abuse, basically,” Brewster said. “They shouldn’t be using this in flea and tick medication if it’s bad for pets.”

Environmental Protection Agency statement

During the period Jan. 1, 2011, until Mar. 31, 2020, there have been a total of 67 human (either minor or symptoms unknown or unspecified) and 1,380 domestic animal incidents reported under section 6(a)(2) of the Federal Insecticide, Fungicide and Rodenticide Act, which states the following: “If at any time after the registration of a pesticide the registrant has additional factual information regarding unreasonable adverse effects on the environment of the pesticide, the registrant shall submit such information to the Administrator.”

EPA uses these data in its regulation of pesticides to help determine whether additional regulatory action is necessary. When considering the above data, one must weigh the number of adverse incidents against the number of doses of the product sold. While sales numbers are confidential business information, EPA does have access to sales figures. The number of adverse reactions is very small in comparison to product sales.

In 2009, EPA took numerous actions to improve the safety of spot-on flea and tick products like PetArmor.

The FDA has put out warnings to owners about adverse side effects on other flea and tick medication products that contain Isoxazoline.

MORE: 

• EPA Evaluation of Pet Spot-on Products: Analysis and Plans for Reducing Harmful Effects
• Fact Sheet for Pet Owners and Veterinarians about Potential Adverse Events Associated with Isoxazoline Flea and Tick Products