MDR1 is a genetic disorder found in many dog breeds. Affected dogs, when treated with certain common drugs such as Ivermectin and loperamide (Imodium), are unable to pump out these drugs from the brain resulting in poisoning and neurologic symptoms ranging from tremors, anorexia and excess salivation to blindness, coma and even death. Some of these drugs such as Ivermectins, which vets prescribe extensively for the treatment of parasite infections, are able to cause toxicity at 1/200th of the dose required to cause toxicity in healthy dogs.
Scientists discovered that these dogs lack a protein (P-Glycoprotein), which is responsible for pumping out many drugs and toxins from the brain, and that affected dogs show signs of toxicity because they are unable to stop drugs from permeating their brains. Researchers have identified that this condition is due to a mutation in the multi-drug resistance gene [MDR1].
LIST OF DRUGS THAT CAUSE SENSITIVITY TO DOGS WITH MDR1 MUTATION
||Do not use these drugs in dogs with MDR1 Gene Defect
Ivermectine substances "Anti parasites": (Diapec®, Ecomectin®, Equimax®, Eqvalan®, Ivomec®, Noromectin®, Paramectin®, Qualimec®, Sumex®, Virbamec®)
Doramectine substances "Anti parasites": (Dectomax® )
Loperamide substances "ant diarrheal ":
Moxidectine substances "Anti Parasites" (Cydectin®, Equest®)
|Use only under close control of veterinarian
Cytostatics "Chemotherapy": (Vinblastine, Vincristine, Doxorubicine, Paclitaxel, Docetaxel, Methotrexat, Vincristine)
Immunosuppressive: (Cyclosporine A)
Heart glycosides: (Digoxine, Methyldigoxine)
Antiarrhythmics: (Verapamil, Diltiazem, Chinidine)
Antiemetics (Ondansetron, Domperidon, Metoclopramide )
Antibiotics (Sparfloxacin, Grepafloxacin, Erythromycin)
Acepromazine (tranquilizer and pre-anesthetic agent) *
Butorphanol "analgesic and pre-anesthetic agent" *
Etoposide, Mitoxantrone, Ondansetron, Paclitaxel, Rifampicin
|| Can be used only in the permitted application form and dose!
Selamectin (Stronghold®), Milbemax® and Advocate® .
* In dogs with the MDR1 mutation, acepromazine and butorphanol tend to cause more profound and prolonged sedation in dogs . It is recommended to reduce the dose by 25% in dogs heterozygous for the MDR1 mutation (MDR1 / N) and by 30-50% in dogs homozygous for the MDR1 mutation (MDR1 / MDR1).