I washed both dogs to remove as much of the Certifect as possible, which had spread an oily coating over most of their backs. Here is a list of potential side effects from the European Public Assessment Report:
"Dogs may show some temporary reactions at the site of application (discolouration, hair loss, itching or redness). The itching and hair loss can in rare cases be more extensive. Dogs that lick the treatment area may salivate, vomit, have blood sugar levels higher than normal, be more sensitive to stimulation, lack energy, and have a slow heartbeat or slow breathing. These signs generally resolve without treatment and within one day. Certifect must not be used on sick animals (with systemic diseases such as diabetes, or with a fever) or convalescent animals. The medicine should not be used in rabbits and cats.
Certifect should not be allowed to enter surface water, as it may be harmful for aquatic organisms."
- EPAR. They can also affect the nervous system of the host animal in some cases. Maggie was lucky that her symptoms went away over the course of 48 hours, and she didn't have seizures, heart issues, vomiting or permanent nervous system issues as some others have reported. She did have a bladder control issue last year, which we thought was a UTI (urinary tract infection) or spay incontinence at the time. We now realize that all "leakage" issues coincided with Frontline application, and our vet has said that we can never use these types of products on Maggie again as she is too sensitive. We won't use these types of products on any of our animals now, as the cats are indoor only and I don't want Duke to have to go through what Maggie did. We're trying a cedar oil flea and tick repellant spray recommended by Save a Dog, a local shelter that advocates holistic treatment rather than chemicals. Hopefully your dog won't have an issue with flea and tick treatments, but if they start having some of the symptoms mentioned and your vet can't find another underlying health issue, ask if it could be a reaction to the "spot on" product.