Who has heard of the phrase ‘multidrug resistance mutation 1 (MDR1)’?
This refers to a specific mutation that can occur at a gene known as the MDR1 gene.
Many herding breeds (most commonly Collies and Australian Shepherds) have a mutation at the MDR1 gene that makes them more sensitive to the negative effects of certain medications. In dogs that possess the MDR1 mutation, this allows higher levels of drugs to enter the brain, increasing neurologic effects of some medications.
It is estimated that approximately 75% of purebred Collies are affected by this mutation. Australian Shepherds have a slightly lower incidence, with only 50% being affected to some degree.
Mixed breed dogs of herding descent have a 35% chance of carrying one or more mutated copies of the gene, while only 10% of Shelties are affected. Other herding breeds, including Border Collies, English Shepherds, German Shepherds, and Old English Sheepdogs, have a less than 5% chance of carrying a defective copy of the MDR1 gene.
This means that in the veterinary industry we have to be very cautious in giving a number of different medications that we would normally not think twice about giving in any other circumstance.
This is why we encourage you to test your dog for the presence of MDR1 through a simple blood test or even a cheek swab sample. This enables us to know for each individual; what medication we can and cannot give safely and also prevents us from depriving and with-holding certain medication needed to treat them effectively because we do not know how this will affect them due to them not being tested .
For more information then please call our friendly team for any advice on 01780 762109