COLLIE HEALTH

MULTIDRUG RESISTANCE (MDR1)

 

What is Multidrug Sensitivity in dogs?

Some dog breeds are more sensitive to certain drugs than other breeds. Collies and related breeds, for instance, can have adverse reactions to drugs such as ivermectin and loperamide (Imodium). 

Drug sensitivities result from 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 cannot 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.

How do I know if my dog is affected?

Approximately three of every four Collies in the United States have the mutant MDR1 gene. The frequency is about the same in France and Australia, so it is likely that most Collies worldwide have the mutation. The MDR1 mutation has also been found in Shetland Sheepdogs (Shelties). Australian Shepherds, Old English Sheepdogs, English Shepherds, German Shepherds, Long-haired Whippets, Silken Windhounds, and a variety of mixed breed dogs.

The only way to know if an individual dog has the mutant MDR1 gene is to have the dog tested. As more dogs are tested, more breeds will probably be added to the list of affected breeds.
 

What drugs should I look out for?

Many different drugs and drug classes have been reported to cause problems in Collies and other herding breed dogs that carry the MDR1 mutation.  We suggest that you link to the Washington State University web site which has a list of drugs that have been researched because information on these drugs changes often.

The most common drugs known to cause neurological signs are listed below.  We suggest that these drugs be avoided completely unless you are absolutely sure the amount to be administered is in the "safe" dosage zone.

Invermectin (antiparasitic agent).

Acepromazine (tranquilizer and pre-anesthetic agent).

Butorphanol (analgesic and pre-anesthetic agent).

Erythromycin, Cyclosporine, Grapiprant,

 Maropitant, Loperamide, Ondansetron,

Afoxolaner, Fluralaner, Sarolaner, Selamectin, milbemycin, and moxidectin (antaparasitic agents).

  Vincristine, Vinblastine, Vinorelbine, Doxorubicin (chemotherapy agents).

 

For more details on these drugs, and others, and the amounts that are recommended to be administered please download this information sheet kindly supplied by Victorian Collie Rescue.

Click here to download Victorian Collie Rescue's MDR1 information sheet

or link to

Click here for the WASHINGTON STATE UNIVERSITY website  

 

COLLIE EYE ANOMALY
(CEA)
 
This is the most common of the Collie eye diseases, but it should be noted that Collies share this disease with several other breeds. Researchers first noted this problem nearly fifty years ago. It was later found to exist in most Collies and in most Collie families. This so-called syndrome, meaning a group of conditions which appear in conjunction with each other, is present prior to birth. Collie Eye Anomaly can be easily checked when the puppies are approx 8 weeks old, by a qualified Ophthalmologist. It is something that your average Veterinarian is not qualified to diagnose. 
 
Can the Collie's eyes become worse? Might he later go blind? The basic answer is "No" as CEA is present prior to birth. However, a dog born with a severe Staphyloma or with Vascular Disease may later suffer loss of sight if a detachment or severe hemorrhage occurs. The majority of dogs that are slightly/mildly affected, will have perfectly adequate eye vision throughout their life. 
 
When the eye problem was discovered more than 50 years ago, it was estimated that 90% of the Collie population was afflicted with some form of eye disease. Because CEA has involved such a large percentage of the breed, eradication has been slow.  ALL reputable breeders eye check not only their breeding stock, but all puppies that are offered for sale.


Contact Details

Jackie Garvin
Gisborne, VIC, Australia