Health And Drug Information - MDR1 mutation

Many different drugs and drug classes have been reported to cause problems in Aussies, Collies and other herding dog breeds that carry the MDR1 Mutation gene.


Aussies and other herding type breeds (Collies, Border Collies, ACD’s and Shelties) can have certain drug sensitivities. Aussies should never be given any of the drugs listed below. Please note Heartgaurd is on the list and can cause seizures in Aussies.  NEVER give Heartguard to an Aussie, choose Interceptor instead.  Also note not all vets are familiar with this list or the MDR1 mutation so make sure you ask what they are going to use.

Drugs that have been documented, or are strongly suspected to cause problems in dogs with the MDR1 mutation:

*  Ivermectin (antiparasitic agent) "Heartgaurd"
* Loperamide (Imodium®; over-the-counter antidiarrheal agent)
* Doxorubicin (anticancer agent)
* Vincristine (anticancer agent)
* Vinblastine (anticancer agent)
* Cyclosporin (immunosuppressive agent)
* Digoxin (heart drug)
* Acepromazine (tranquilizer)
* Butorphanol (pain control)




Desciduous Teeth (puppy)

Incisors      3-4 weeks

Canines      3 weeks

Premolars  4-12weeks

Molars       none


Permanent Teeth

Incisors      3-5 months

Canines      4-6 months

Premolars  4-6 months

Molars        5-7 months