College of Veterinary Medicine

Veterinary Clinical Pharmacology Lab

Multidrug Sensitivity in Dogs

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 (ivermectin, milbemycin and related drugs), the antidiarrheal agent loperamide (Imodium), and several anticancer drugs (vincristine, doxorubicin, others). These drug sensitivities result from a mutation in the multidrug resistance gene (MDR1 gene). At Washington State University's College of Veterinary Medicine you can test your dog for multidrug 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.

The Partnership for Preventive Healthcare, is an initiative jointly sponsored by the American Animal Hospital Association and the American Veterinary Medical Association. Together the two associations offer a set of Canine and Feline Preventive Healthcare Guidelines. One of the important recommendations is that dog owners use genetic testing—like the MDR1 test —as part of an overall healthcare plan for their pets.

Test Your Dog


Video showing how to collect samples from your dog


The discovery of the mutation of the multi-drug resistant gene (mdr1), establishment of testing procedures, and development of all reagents was made by Washington State University. It is also a patent protected diagnostic test offered exclusively by Washington State University that has not been licensed to any other entity in the United States. It is licensed in Australia and Europe.
Unless testing is conducted by Washington State University's Veterinary Clinical Pharmacology Laboratory, Washington State University cannot control quality and accuracy and consumers may risk receiving inaccurate results.


Most Commonly Affected Breeds

Australian Shepherd
Australian Shepherd (Mini)
Long-haired Whippet
Silken Windhound

Click here for a complete list


What's New?

AVMA and AAHA recommend genetic screening for dogs

Include your pet's MDR1 status on his/her tag

MDR1 test featured among 'best pet products' on "Good Morning America"

Message from Toni

Ginger's Story: 6 year old Australian Shepherd x Golden Retriever

Contact Us

Veterinary Clinical Pharmacology Laboratory (VCPL)
Washington State University
College of Veterinary Medicine
P.O. Box 609
Pullman, WA 99163-0609
Phone: 509-335-3745
FAX: 509-335-6309

Last Edited: Jan 07, 2015 9:10 AM   

Veterinary Clinical Pharmacology Laboratory PO Box 609 , Washington State University, Pullman WA 99163-0609, 509-335-3745, Contact Us Safety Links