Label changes are under way for spot-on flea and tick preventatives, and while modifications are still in the works, one warning is likely to be stressed: Topical pet parasiticides intended for dogs can be fatal if used on cats.
That change and others like it are coming via pressure from the U.S. Environmental Protection Agency (EPA), which has been investigating a surge in adverse events reportedly tied to spot-on parasite-control treatments, with reactions ranging from minor skin irritations to seizures and deaths.
The EPA began looking at the issue three years ago
, when the number of reported adverse events in pets exposed to topical flea and tick products reached 44,000 in 2008, up 53-percent compared with the previous year.
In response to the 2008 increase, the EPA analyzed 21 different products registered by Bayer, Fort Dodge Animal Health (now Pfizer), Hartz Mountain Corp., Merial, Pet Logic, Sergeant’s Pet Care Products, Inc., Summit VetPharm and Wellmark. The topical parasiticides produced by these companies are considered “spot-on” because they come as liquids contained in small, plastic vials that are squeezed onto the skin of a pet’s back, usually between the shoulder blades. Spot-on treatments typically are applied every few weeks during flea and tick season to prevent and manage infestations.
The EPA regulates these products because they're categorized as
pesticides rather than drugs, which are controlled by the U.S. Food and
Drug Administration. Any formula to treat fleas and ticks that does not cross the skin barrier must be EPA-registered. The topical products in question include active ingredients in all pesticide classes: cyphenothrin, phenothrin, permethrin, imidacloprid, dinotefuran,
fipronil, amitraz, etofenprox, S-methoprene, pyriproxyfen and
Some, including veterinarians, pet owners and manufacturers, blame product misuse for the rise in adverse events associated with spot-on flea and tick treatments. In March 2010, the EPA concluded that spot-on labels needed to better warn against using treatments meant for dogs on cats. The agency also wanted manufacturers to lower recommended dosages for some pets in hopes that fewer animals would become over-medicated.
The EPA continues to back this stance despite the fact that adverse reactions to spot-on flea and tick treatments more recently have declined in numbers. In 2009 and 2010, adverse events reported to the EPA totaled 38,062 and 27,532, respectively. Aggregate
numbers for 2011 have not been calculated.
The EPA attributes the decrease to
a variety factors, including increased public awareness that flea and
tick treatments can induce negative and sometimes life-threatening side
effects in pets, especially if used incorrectly.
To mitigate future incidents, the agency continues to pursue label modifications. In a seven-page letter
to spot-on registrants dated Sept. 30, 2011, the EPA asked companies selling spot-on treatments to submit within six months a draft of label and packaging changes that include, in part:
• Enlarged label font sizes and animal images that allow users can quickly distinguish the species for which the product is intended;
• Specific language on labels of products intended for dogs that warns against their use on cats; repeating the words "dog" and "cat" throughout product instructions; and adding a “cat prohibition icon” to the lower right corner of packaging for canine flea and tick treatments;
• More information about possible adverse events and instructions for pet owners to contact the product manufacturer and a veterinarian if a suspected reaction occurs;
• Narrowed product weight ranges and appropriate pictures of the weight ranges;
• More clearly defined species, age and weight ranges.
It's unclear whether manufacturers ultimately will make all of the EPA's suggested label changes; the six-month window for submitting draft language to the EPA ended in April. While the EPA indicates that it's going back and forth with companies to approve new labels and packaging, regulators would not identify whether any changed labels currently are in the marketplace.
"The agency is beginning to see applications for amendments to product labels in response to the EPA letter," spokesman Dale Kemery said in response to a query from the VIN News Service. "Over the next few months, EPA will be reviewing these amendments … to ensure that the necessary changes are adequately addressed.”