NORMAN — Dear Dr. Fox: I have just adopted a 6-month-old female Australian shepherd mix from an adoption network. A friend warned me that this breed can get ill and die from heartworm prevention medication. I respect his advice — he is a dog trainer and seems to know a lot. What is your opinion?
— K.P., Silver Spring, Md.
Dear K.P.: First, let me say that I now endorse yearround heartworm preventive medication for most dogs. Your dog should also get periodic blood tests to check for heartworms because of climate change, traveling and the fact that more than 70 species of mosquitoes can transmit this disease.
Your veterinarian can determine if it is safe to temporarily stop the monthly medication during the winter season.
You raise an important issue, which needs to be addressed. I hope all readers with dogs will take note because dogs have adverse drug reactions, and many drugs are now being prescribed for the dogs’ entire lives.
Washington State University’s College of Veterinary Medicine advises, “Many herding breed dogs have a genetic predisposition to adverse drug reactions involving over a dozen different drugs. The most serious adverse drug reactions involve several antiparasitic agents, the antidiarrheal agent loperamide and several anticancer drugs. These drug sensitivities result from a mutation in the multi-drug resistance (MDR1) gene. At Washington State University’s College of Veterinary Medicine, you can test your dog for multi-drug sensitivity and prevent serious adverse drug reactions. We can work with your dog’s veterinarian to find appropriate drug doses or alternative drugs for your dog based on results of MDR1 testing.”
Consult with your veterinarian about this genetic blood test, also available from other laboratories.
The university also posted the following breed prevalence as an approximate percentage frequency of the genetic mutation causing multidrug sensitivity: Australian shepherd, 50 percent; mini Australian shepherd, 50 percent; border collie, 5 percent; collie, 70 percent; English shepherd, 15 percent; German shepherd, 10 percent; herding breed cross 10 percent; long-haired whippet, 65 percent; McNab, 30 percent; mixed breed, 5 percent; old English sheepdog, 5 percent; Shetland sheepdog, 15 percent; silken windhound, 30 percent.