Some breeds of dogs are more sensitive to certain drugs compared to other breeds. For example, Collies, Border Collies, German Shepherds, Shelties, Australian Shepherds and other breeds are often more sensitive to the antiparasitic drug, ivermectin.
Why are some breeds
more sensitive to the effects of drugs than other breeds? Which drugs
have been reported to cause problems? At Washington State University's
College of Veterinary Medicine you can get your dog tested for drug
sensitivity and keep up with the latest research.
It is well known that Collies and related breeds can have adverse reactions
to drugs such as ivermectin, loperamide (Imodium®), and others. It was
previously unknown why some individual dogs were sensitive and others were
not. Advances in molecular biology at the Veterinary Clinical Pharmacology
Laboratory at Washington State University's College of Veterinary Medicine
have led to the discovery of the cause of multi-drug sensitivity in affected
dogs. The problem is due to a mutation in the multi-drug resistance gene
(MDR1). This gene encodes a protein, P-glycoprotein, that is responsible for
pumping many drugs and other toxins out of the brain. Dogs with the mutant
gene can not pump some drugs out of the brain as a normal dog would, which
may result in abnormal neurologic signs. The result may be an illness
requiring an extended hospital stay--or even death.
Last Updated: May 19, 2016