The last time I gave Maybelle her dose of Revolution I swear she had a weird reaction. When we were going to bed that night she got up on her couch and started panting heavily (it was October in Connecticut, there was no reason for this). She looked very…strange… I sat there and pet her for a minute while she relaxed but the next day I started doing some homework and I started learning about problems many herding breeds have with certain drugs thanks to mutated MDR1 genes.
I decided to write about it because I’ve seen some misleading info out there. For instance, I was researching a different flea and parasite treatment and came across a message board where one user told a woman whose friend’s Border Collie started having seizures after taking the drug (Trifexis) that this particular tablet was not recommended for herding breeds because of the MDR1 gene, though that does not seem to be true. Ivermectin — the active ingredient in most common heartworm meds — is one of the drugs known to cause toxicity in dogs with the mutant MDR1. Trifexis is not recommended for dogs with epilepsy or seizure disorders, however, so I’m guessing the poor Border Collie had an underlying problem with seizures.
I still haven’t decided what to do. Today I was chatting without trainer about Maybelle’s strange late-night “episodes” and decided that I was going to bring a video to my vet when we go for her rabies shot, to rule out a seizure problem. I also intend on talking to her about this MDR1 thing. Cattle Dogs aren’t on the list for dogs effected by this particular problem but they did pop up on a list of breeds that could be adversely effected by one of the topical flea preventatives (though of course I can’t find it now).
In any case, if you think your dog might have a herding breed in her background, be sure to do your homework and talk to your vet.