Health Topics

Are heartworm prevention products safe if my dog has the MDR1 mutation?

All heartworm products labeled for dogs in the United States have been tested in dogs with the MDR1 mutation as required by the FDA and have been found to be safe. Drugs such as ivermectin, selamectin, milbemycin, and moxidectin, are commonly used to treat and prevent parasites like heartworms. At low doses, such as those […]

Dog breeds commonly affected by MDR1 mutation

Dogs with a mutation in the MDR1 (multidrug resistance 1) gene may have severe and life-threatening reactions to some common drugs. Research has shown the mutation occurs more frequently in certain breeds. Approximately three of every four collies in the United States have the mutant MDR1 gene. The frequency is about the same in France […]

Rough Collie