MDR1 & Aussies

MDR1 in Australian Shepherds: What You Need to Know

 

What is MDR1?

 

MDR1 (Multi-Drug Resistance 1) is a genetic mutation that affects the ability of certain dog breeds, including Australian Shepherds, to process certain medications. This mutation impacts the function of the P-glycoprotein, a protein that helps to transport drugs and toxins out of the brain and into the bloodstream. Dogs with the MDR1 mutation may experience toxic reactions to specific medications that are typically safe for other dogs.

 

Why is MDR1 Important for Australian Shepherds?

 

Australian Shepherds, along with some other herding breeds (such as Collies and Shetland Sheepdogs), are known to carry the MDR1 gene mutation. Understanding this mutation is crucial for pet owners and veterinarians to prevent adverse drug reactions that could endanger your dog’s health.

 

Symptoms of MDR1 Sensitivity

 

If an Australian Shepherd with the MDR1 mutation is given a contraindicated medication, they may exhibit the following symptoms:

 

    •    Vomiting

    •    Diarrhea

    •    Lethargy

    •    Loss of appetite

    •    Neurological signs (such as tremors, seizures, or disorientation)

    •    Excessive salivation

 

If you suspect your dog has been given one of the drugs listed below and exhibits any of these symptoms, contact your veterinarian immediately.

 

Medications to Avoid

 

Dogs with the MDR1 mutation may have adverse reactions to the following medications:

 

    1.    Ivermectin: Commonly used as a dewormer and heartworm preventative. In affected dogs, it can cause neurological toxicity.

    2.    Loperamide (Imodium): Often used to treat diarrhea. Affected dogs can experience severe sedation, ataxia, and respiratory depression.

    3.    Acepromazine: A tranquilizer and sedative. This can lead to excessive sedation and cardiovascular complications in MDR1-sensitive dogs.

    4.    Dexamethasone: A corticosteroid that may cause problems in dogs with the mutation due to its effects on the brain.

    5.    Vincristine and Vinblastine: Chemotherapy drugs used to treat certain cancers; these can lead to severe neurotoxicity in affected dogs.

    6.    Butorphanol: An opioid analgesic that can cause significant sedation in dogs with the mutation.

    7.    Moxidectin: A heartworm preventative that may lead to toxicity.

    8.    Milbemycin oxime: Another heartworm medication that can cause adverse effects.

    9.    Selamectin: A topical flea treatment that can be harmful.

    10.    Praziquantel: Used to treat tapeworms, this may be problematic in certain combinations.

    11.    Fipronil: A flea and tick treatment that could pose risks.

    12.    Grapiprant: Used for pain and inflammation; caution is advised.

    13.    Morphine and Buprenorphine: Opioid pain relievers that may cause significant sedation.

 

Additional Considerations

 

    •    Antidepressants and Anti-anxiety Medications: Certain medications in these categories can also pose risks, and specific drugs can vary based on the individual dog’s sensitivity.

    •    Chemotherapeutic Agents: Other chemotherapy drugs may also affect MDR1-sensitive dogs, so it’s essential to discuss any cancer treatment plans with a veterinarian familiar with this mutation.

 

Testing for MDR1

 

If you own an Australian Shepherd or are considering adopting one, it is advisable to have your dog tested for the MDR1 mutation. A simple blood test can determine whether your dog is a carrier of the mutation. This is especially important if your dog may require medication in the future.

 

What You Can Do

 

    1.    Consult Your Veterinarian: Always inform your veterinarian about your dog’s breed and potential MDR1 sensitivity when discussing medications.

    2.    Keep Records: Maintain a list of medications that are safe for your dog and share this with any pet sitter, groomer, or boarding facility.

    3.    Educate Yourself and Others: Familiarize yourself with the signs of toxicity and the medications to avoid. Ensure that anyone who handles your dog is aware of their sensitivity.

    4.    Emergency Plan: Have an emergency plan in place that includes contacting your veterinarian or a nearby animal hospital in case of accidental exposure to prohibited medications.

 

Conclusion

 

Being informed about the MDR1 mutation in Australian Shepherds is vital for ensuring your dog’s health and safety. By avoiding specific medications and working closely with your veterinarian, you can help prevent potentially dangerous reactions and ensure a healthy, happy life for your furry friend.