Dogs and cats treated with products that are supposed to protect them from fleas and ticks could be at an increased risk for neurological problems, health regulators warned on Thursday.
The U.S. Food and Drug Administration warned pet owners and veterinarians of pills and chewables that contains the pesticide called isoxazoline that ward off tick and flea infestation.
The treatments include products sold under the brand names Nexgard, Simparica, Credelio, and Bravecto.
NBC News said that isoxazoline products work by interfering with the nervous system of the insects, but the chemical does not appear to interfere as much with the nervous system of mammals. A group of researchers has even proposed testing the use of this pesticide to protect people against mosquitoes and other insect bites.
The warning was issued after routine data collection showed that some pets given isoxazoline class treatments experienced adverse events.
The FDA reviewed studies and other data on isoxazoline products and found links with neurological adverse reactions, that include ataxia, muscle tremors, and seizures in some cats and dogs. Ataxia is a condition characterized by the loss of control of bodily movements, which causes animals to stumble or twitch.
The affected products are still safe for most animals, but the agency said they have been linked with these events. It also said that while most dogs and cats have not had neurological adverse reactions, it is possible that seizures would occur in animals without prior history.
"Although these products can and have been safely used in the majority of dogs and cats, pet owners should consult with their veterinarian to review their patients' medical histories and determine whether a product in the isoxazoline class is appropriate for their pet," reads the FDA Fact Sheet for Pet Owners and Veterinarians.
The labels of the affected products, more commonly sold as flavored chewables, already include information about the risk of neurological side effects, but the FDA said that these treatments will soon have a new label information that will highlight neurological events.
"The agency is asking the manufacturers to make the changes to the product labeling in order to provide veterinarians and pet owners with the information they need to make treatment decisions for each pet on an individual basis," the FDA said in a statement.
Pet owners who think their dog or cat has experienced an adverse reaction are urged to contact their veterinarian. Adverse drugs events should also be reported to the drug's manufacturers, who are required to report the information to the FDA.