5 Facts About Multi-Drug Resistance Gene (MDR1) in Dogs | The Goody Pet
5 Facts About Multi-Drug Resistance Gene (MDR1) in Dogs

5 Facts About Multi-Drug Resistance Gene (MDR1) in Dogs

PETE DECKER / AUGUST 4, 2018 / DOGS

Earlier, it was believed that p-glycoprotein is contained in cancer cells that help them to resist the effects of chemotherapy. However, recent studies have shown that p-glycoprotein is found in normal cells as well.

It plays the important function in the process of the blood-brain barrier that prevents bloodstream chemicals from making their way into the brain.

This p-glycoprotein is abnormally produced in dogs that have two copies of the MDR1 gene.

This results in drugs and chemicals reaching their brain and causing neurological dysfunctions such as seizures, disorientation and complete loss of sight. If you are a new pet parent, this could be a reason to be concerned about and the only solution is to get a DNA dog test kit (here's our updated buyer's guide) that could find out whether your dog has the gene mutation or not.

If you do find out that your dog or any other dog you know has the MDR1 gene mutation, here are 5 things that you must be aware of.

Drugs To Avoid Giving Your Dog


There are certain drugs that you should avoid giving your dog if he is a herding breed or the DNA test tells you that he has the MDR1 gene mutation. Butarphanol, doxorubicin, common antibiotics like erythromycin and rifampin, loperamide, vincristine and vinblastine, high doses of ivermectin, moxidectin, selamectin, and milbemycin are the drugs that you must avoid at all costs.

Affected Breeds


The most commonly affected breeds are Collies, Australian Shepherds, Silken Windhounds, Longhaired Whippets and McNabs. Breeds like German Shepherd, English Shepherds, and Old English Sheepdogs have also been detected with this mutation

Heartworm Preventives Can Be Used


Unlike what you used to be believed earlier, heartworm preventive medication can be administered monthly without any worry. The recommended levels are safe for dogs with the MDR1 gene mutation.

It Affects Mixed Breed Dogs Too


Your mixed breed could have an ancestral line that dates back to a herding breed.

Therefore, if you have a mixed breed, it is essential to get a DNA test done at the earliest to rule out MDR1 gene mutation.

Your mixed breed might look nothing like a herding breed but that does not make it safe from the mutation. Studies have shown that mixed breed dogs that have no resemblance to herding breeds do come up with this particular gene mutation.

A commonly used drug, ivermectin could be dangerous for such dogs if given in higher doses and to prevent that, getting a test done at the earliest is the best way out.

Puppies Can Be Tested


If you are not sure about the parents of a puppy that you have adopted, you can get it tested even in infancy. You need not wait until a certain age to get the test done. If you have adopted your puppy from a certified breeder then he will provide you a copy of the DNA tests that have already been conducted on the puppy so that you can carry it along to your veterinarian on your first visit.

Final Thoughts – Important To Get Tested!


With a DIY dog test kit, prices are affordable to get tested. It's a small sum to pay for a lifetime of happiness with your canine companion.