PULLMAN – Every dog has his day, and someday, every dog may have his own drug profile.
Washington State University veterinary pharmacologist Katrina Mealey has launched a study of how different breeds of dogs react to common medications, and is asking dog owners in the Pacific Northwest for their help.
The work was spurred by Mealey’s discovery a few years ago that dogs of herding breeds have a high risk of carrying a mutation that renders normally harmless drugs deadly.
“Different breeds react differently to different drugs,” said Mealey. “If you test it in a beagle, it’s fine,” but in a herding dog the same drug could be lethal.
In the new study, Mealey hopes to get DNA samples from at least 25 unrelated dogs of every one of the 150-plus breeds recognized by the American Kennel Club and United Kennel Club. Donor dogs need not be registered with those organizations, but they must have an AKC or UKC “puppy number” the researchers can use to confirm their ancestry five generations back.
“We’re not snobby,” Mealey said. “We just need to know that they’re purebred and they’re not related to another dog in the study. We don’t want to find a family problem instead of a breed problem.”
To obtain DNA for analysis, the researchers will draw 6 milliliters of blood – about a teaspoonful.
Dog owners interested in participating in the study are asked to schedule an appointment with veterinary technician Denise Waiting at 509-335-0711 or dwaiting@wsu.edu. Samples may be collected at the WSU Veterinary Teaching Hospital or elsewhere in the region, by arrangement with Waiting.
Mealey and geneticist Josh Akey of the University of Washington will search the DNA of every donor for mutations that affect the body’s response to drugs. They are particularly interested in a gene that in humans is involved in processing more than half of all pharmaceutical agents known.
Mealey hopes the work will eventually lead to the development of simple tests that dog owners and breeders can use to determine the safest and most appropriate drug treatments for individual dogs.
In her earlier work, Mealey found that three-quarters of collies and up to 10 percent of other herding breeds, such as Shetland sheepdogs and Old English sheepdogs, carry a mutation that disables a protein needed to pump drugs out of cells. With the mutant form of the protein, drugs accumulate inside cells and eventually reach toxic levels.
In clinical tests, normal collies given immodium (an over-the-counter anti-diarrheal medication) showed no adverse effects. Collies with the mutation, however, began to stagger and become comatose.
All the dogs in Mealey’s trial recovered after being given an antidote and were later adopted by area residents. Unfortunately, she said, many dogs nationwide were not so lucky.
“Dogs were euthanized for horrible neurologic problems, when all they had was this adverse reaction to the drug,” she said. “It was interesting that this was so breed-related. And as a veterinarian, I know of many other adverse drug effects that seem to be breed-related” – such as liver problems in Labrador retrievers given the anti-arthritis drug Rimadyl. “So we want to extend this to help other breeds.”
