Seresto Pet Collar Review

Over the past several years, EPA has been improving its method for considering pet product-incidents, such as those reported for Seresto collars, in the pesticide registration and re-evaluation process. As part of this effort, and due to the number of Seresto-related incidents reported to EPA, the Agency began an in-depth review of the incidents of Seresto collars in 2021.

EPA has reviewed an extensive set of data it required Elanco, the current registrant of Seresto collars, to submit and reviewed the many incidents reported to EPA’s Incident Data System to determine whether the collars may contribute to an elevated number of pet-related incidents. Throughout the review process, EPA consulted with FDA, which regulates similar products for cats and dogs, including flea and tick products that are ingested. EPA used information gathered during this review process to make its determination about the product.

EPA’s Incident Review Findings

EPA’s scientific review of Seresto-related incident reports identified the need for more detailed incident reporting and public outreach. EPA analyzed all incidents that reported death for Seresto. This included 1,400 deaths reported to EPA from 2016-2020, which represent 2 percent of all Seresto incidents reported for these years. In many of the death-related incidents, critical details of the incident were often missing, preventing the Agency from determining the cause of the death.

The only reported deaths that were found to be “probably” or “definitely” related to Seresto product use were associated with mechanical strangulation or trauma caused by the collar, often associated with a failure of the release mechanism.

For all other deaths, EPA did not identify cases with a probable or definite association between collar use and death, often due to other factors impacting the animal, such as an existing medical condition. In addition, the rate of deaths reported for Seresto was similar to that for other pet products reviewed. E

EPA also analyzed all non-lethal incidents, such as neurological symptoms. In some incidents with moderate or severe clinical sign removal of the collar seemed to alleviate symptoms and/or reapplication of the collar coincided with a reoccurrence of symptoms. Based on these findings, Elanco, the registrant of Seresto, has agreed to implement the following measures:

• To alert veterinarians and consumers of potential risks, the terms of continued registration require Elanco to include label warnings on Seresto products that describe common adverse effects that have been reported, along with instructions to remove the collar if those effects occur and instructions on how to report the incident. Elanco also must develop an outreach program to more effectively communicate with veterinarians and the public on the risks of using the product and other similar pesticides on pets.
• To improve the quality of data reported when receiving reported incidents from consumers, Elanco must pursue additional information to the greatest extent possible to ensure that complete details of each event are captured. This information includes whether the pet had any pre-existing conditions or previous history of the reported condition. The Seresto pet collar registration has also been split into two registrations, one for cats and one for dogs, to make comparison of incident data across products easier in the future. Elanco must report incident and sales data to EPA on an annual basis.
• To reduce the risk of strangulation, Elanco must evaluate potential changes to the emergency release mechanism of Seresto pet collars to prevent death by strangulation or choking. The company must submit a report detailing the data and analysis collected and performed in pursuit of this effort within one year. Based on this evaluation, EPA may require a modified release mechanism for the Seresto collar.
• To allow for the continued evaluation of reported incidents, EPA has limited its current approval of Seresto collar registrations to five years. EPA will continue to evaluate Seresto incident data over that period.

To learn more, read EPA’s decision document.

Frequent Q&As

1. What are the potential risks of using Seresto pet collars on dogs and cats?

When used according to label instructions and precautions, pet products such as Seresto pet collars can be very effective, but when misapplied or not used according to directions, your pets may be unnecessarily exposed to pesticides and could become ill. More commonly reported adverse events inude itching for dogs and hair changes near the collar application site for cats. Less common, but more serious reported adverse events, include neurological symptoms, such as convulsions or ataxia.

Monitor your pet for side effects or signs of sensitivity after applying the product, particularly when using the product on your pet for the first time. Consumers whose pet experiences adverse reactions from treatment with a flea and tick product should consult their veterinarian immediately. They should also contact the National Pesticide Information Center, an EPA information-sharing partner that has staff who are specially trained in responding to pesticide exposure incidents, including those involving pets. For flea and tick collars specifically, pet owners should remove the collar immediately if the pet experiences any adverse reaction. In addition, consumers whose pets experienced an adverse reaction from pet collars or topical treatments should also report the incident on EPA’s website at www.epa.gov/pets.

2. Why didn’t EPA cancel Seresto pet collars?

Seresto pet collars continue to meet EPA’s standards under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) while providing important flea and tick prevention for dogs and cats, and lice control for dogs. The new mitigation measures will aid in the continued review of this product and help raise awareness in the veterinary and consumer community about potential risks from pesticide products used on pets. The new measures will also provide more information to users about how to prevent and report adverse reactions from Seresto pet collars.

3. When will the labels changes take effect?

Elanco must implement the new registration requirements by the next printing of Seresto pet collar labels, which must occur in the next 12 months. Elanco must split the pet collar registration into two registrations, one for cats and one for dogs. The company must also add label warnings on Seresto products that discuss common adverse effects that have been reported, along with instructions to remove the collar if those effects occur and instructions on how to report the incident.

4. Why is EPA continuing to review Seresto pet collars? How will EPA continue to review Seresto pet collars in the next few years?

EPA is committed to improving the process by which pet product-related incidents are considered in the pesticide registration and re-evaluation process. The Agency is requiring Elanco to report incident and sales data on an annual basis and provide additional information about incidents whenever possible. Any new data collected on Seresto will be analyzed by EPA.

5. How does the Whitepaper A Modern Approach to EPA and FDA Product Oversight impact the registration of Seresto pet collars?

The EPA and FDA whitepaper describes the current challenges and potential opportunities of a modernized approach to regulation of certain products, including products like Seresto that are topically applied to animals to control fleas or ticks. One aspect of that proposed modernized approach includes a process for transferring oversight of flea and tick pet products, such as Seresto pet collars, from EPA to FDA. The proposals in the whitepaper do not yet impact the registration of Seresto pet collars.