MDR1 Drug Sensitivity

ABCB1

Clinical

This genetic variant makes some dogs sensitive to certain medications, including some dewormers, anti-diarrheals, pain medications, and chemotherapies. Side effects may be stronger than expected, so it’s important your vet knows before prescribing.

Signs and symptoms

MDR1 often presents in young adulthood, only because this is most commonly when a dog is first exposed to a problem drug like high dose ivermectin or acepromazine.

Symptoms arise after a dog has received an MDR1 problem drug or dosage, and can range from vomiting and diarrhea to lethargy, seizures, or coma.

Diagnosis

Treatment

What to do if your dog is at risk

Genetic information

The Multidrug Resistance, ABCB1 mutation, is particularly common in herding breeds including Australian Shepherds, Collies, and Border Collies, though many other dog breeds are affected. The veterinary adage, "White feet don't treat!" draws from the fact that many high risk breeds often have white markings on their feet; however, we know now that MDR1 is common in many dog breeds and mixes, many of whom do NOT have white feet!

Gene: ABCB1
Inheritance type: codominant
Clinical category: Clinical