from the American Veterinary Medical Association
November 15, 2013

“…A summary of the pathology/necropsy reports from an independent pathologist has determined that the cause of deaths were unrelated to the administration of Trifexis®. The summary was derived from the individual pathology/necropsy reports which led attending veterinarians to also conc…lude that Trifexis® was not the cause of death.”

The official autopsy reports are available to the public here:

“A November 2013 media report has focused on some pet owners’ beliefs that their dogs died due to the use of Trifexis®, a heartworm preventive and intestinal parasite and flea therapeutic. There also have been statements on social media alleging illness and death due to the medication. The manufacturer, Elanco, and the FDA are aware of these complaints. According to reports, the deaths have not been definitively linked to the drug.

Our hearts go out to those who’ve lost their pets and who feel it may be due to a medication. It’s always difficult to lose a pet, and we know it can be even harder to lose one unexpectedly. However, heartworm and parasite prevention is critical to your pet’s health, so please do not stop giving your pet his or her preventive. Contact your veterinarian if you have concerns about your pet’s preventive medication or would like to discuss other medication options.

We encourage all pet owners to consult with their veterinarians if they have any questions about their pet’s medication, including the possible risks associated with its use and any measures that can be taken to reduce those risks.

If you feel your pet has experienced an adverse event from a medication, consult your veterinarian immediately. To report an adverse event associated with a veterinary drug, you should contact the manufacturer. The manufacturer is required to provide this information to the FDA.

For more information about heartworm and its prevention, visit the American Heartworm Society’s page.” ( )

Schedule Online
Skip to content