The MDR1 (multidrug resistance 1) gene mutation is common in collies and other herding breeds, and while it is less likely to occur in a mixed breed, it is still possible, and testing is recommended to determine the risk to your pet. The mutant gene was found in a Saint Bernard mix that had an adverse drug reaction.
What is MDR1? MDR1 is the abbreviated name of a gene called Multi-Drug Resistance 1. A mutation of this gene causes sensitivity to Ivermectin and a number of other drugs. Dogs with the mutation will react to those drugs. Whether a dog reacts depends on the dosage of the drug.
Multidrug resistance is a genetic defect in a gene called MDR1. If your Australian Cattle Dog has this mutation, it can affect his processing of many drugs, including substances commonly used to treat parasites, diarrhea and even cancer.
The phrase 'multidrug resistance mutation 1 (MDR1)' refers to a specific mutation that can occur at a gene known as the MDR1 gene, also known as the ABCB1 gene. "a mutation at the MDR1 gene that makes them more sensitive to the negative effects of certain medications.”
October 19, 2021. Dogs with a mutation in the MDR1 (multidrug resistance 1) gene may have severe and life-threatening reactions to some common drugs. Research has shown the mutation occurs more frequently in certain breeds. Approximately three of every four collies in the United States have the mutant MDR1 gene.
The manufacturer of Nexgard has tested the product for safety in dogs with the MDR1 mutation. No adverse effects were observed. Dogs with the MDR1 mutation are not at increased risk for adverse effects.
Drugs such as ivermectin, selamectin, milbemycin, and moxidectin, are commonly used to treat and prevent parasites like heartworms. At low doses, such as those used in heartworm prevention, these drugs have been shown to be safe even for dogs with the MDR1 mutation.
Genetic testing for MDR1 is recommended to identify dogs at risk for multidrug sensitivity. Affected dogs will only exhibit signs of neurotoxicity if exposed to certain drugs. Test results should be shared with the dog's veterinarian prior to pharmacological treatments.
Australian Shepherds have a slightly lower incidence, with 50% being affected to some degree. Mixed breed dogs of herding descent have a 35% chance of carrying one or more mutated copies of the gene, while only 10% of Shelties are affected.
When considering the use of macrocyclic lactones such as ivermectin or moxidectin in dogs, veterinarians have followed the adage, “white feet, don't treat.” This refers to the known sensitivity of Scotch collies (both rough and smooth) to neurotoxicity when administered these drugs at higher than label doses.
MDR1 is an autosomal dominant genetic disorder, which means that only one copy of the gene is necessary for the dog to be affected. There is therefore no such thing as an MDR1 carrier.
The MDR1 (−/−) genotype was present in 35.9% of Collies (95% CI =26.9%–45%), and the MDR1 (+/−) genotype was present in 50.5% Collies, 31.3% Australian Shepherds, and 15.8% Shetland Sheepdogs (95% CI =26.9%–45%, 41.1%–59.9%, and 7.7%–23.9% respectively) (Table 1).
The answer to this question is not as simple as “yes” or “no.” Some people who have allergies may be able to tolerate Australian Shepherds because of the double coat that these dogs have. This means that there may be less shedding and dander than with other breeds.
Ivermectin should not be used in dogs younger than 6 weeks of age or in dogs without a current negative heartworm test. Some breeds of dogs (e.g., collies, sheepdogs, and collie- or sheepdog-cross breeds) are more sensitive to ivermectin than others.
Neither of these product contain Ivermectin or mectin derivative active ingredients. Both are a monthly product that will prevent heartworm infestations and also control all intestinal worms including roundworm, hookworm, whipworm and tapeworm.
Are NexGard and NexGard SPECTRA safe to use for any breed of dog? NexGard and NexGard SPECTRA have been shown to be safe and effective in various breeds of dogs (including Collie breeds) when used as directed and, can be given to puppies from 8 weeks of age, providing they weigh at least 2 kg.
A safe anesthetic protocol for dogs with the mutation of MDR1 consists in a 50% reduction of the normal dose with the drugs involved, specially morphine, butorphanol, buprenorphine and acepromazine.
A Pesticide That Targets the Central Nervous System
Isoxazolines are neurotoxic to more than just insects; they also affect mammals. There is a reason why so many dogs experience seizures, ataxia, and tremors after taking NexGard — the pesticide compromises the dog's central nervous system.
This sensitivity is because of a mutation in what is known as the MDR1 gene. In dogs who have the mutation, the drug crosses the blood-brain barrier and causes neurological damage, which can be lethal.
Dogs with the mutated MDR1 gene have an alteration in the blood brain barrier affecting transport of drugs such as ivermectin. Exposure to these drugs may result in serious neurological symptoms, such as hypersalivation, ataxia, blindness, tremor, respiratory distress and even death.
Only $75 with results in 7 business days. The Multidrug Resistance 1 MDR1 Test is a fast and effective way of determining whether or not your dog has the mutated Multidrug Resistance MDR1 gene, also known as the ABCB1 gene, or is likely to pass it on to any offspring.
The MDR1 gene mutation is hereditary and is passed from parents to offspring. Each dog inherits 2 copies of the MDR1 gene—1 copy from each parent. Animals that inherit 2 abnormal copies (homozygous) will produce no normal p-glycoprotein and will be most strongly affected.
The product was well tolerated in dogs with a deficient multidrug-resistance-protein 1 (MDR1 -/-). However, in such sensitive breeds (which may include, but not necessarily limited to, Collies and related breeds), the recommended dose should be strictly observed. Wash hands after handling the product.