Certain breeds such as the Border Collie are genetically hypersensitive to the medication. In these breeds, Ivermectin can pass directly to the brain and be toxic or even lethal. This genetic sensitivity is due to a mutation in what is called the MDR1 gene.
Ivermectin is a very commonly used wormer, suitable for horses, cattle, sheep, birds, and a wide range of small mammals. It is occasionally used in dogs – but never in collies and other herding breeds.
Ivermectin sensitivity in collies is associated with a deletion mutation of the mdr1 gene.
Some breeds of dogs (e.g., collies, sheepdogs, and collie- or sheepdog-cross breeds) are more sensitive to ivermectin than others. This is typically due to a specific genetic mutation (MDR1) that makes them less able to tolerate high doses of ivermectin.
Interceptor is the ONLY safe heartworm prevention medication for Collies, Collie-mixes, Shelties and Sheltie-mixes. This is because Interceptor does not contain the drug ivermectin, which is known to have deadly effects in these and some other breeds. Heartworm prevention is easy.
Ivermectin Toxicity
Ivermectin may not be safe for collies and similar herding breeds at higher dosages that would be safe in other dogs. The increased sensitivity of these breeds is a result of a mutation of the MDR1 (multi-drug resistance) gene.
Both Interceptor and Milbemax contain: Milbemycin oxime and praziquantel which are both safe in use for dogs that are positive for MDR1 gene. By switching to either of these products it will be much easier to protect them from heartworm and intestinal worms without the need to dose daily with dimmitrol.
Ivermectin and other related drugs (milbemycin, selamectin) are commonly used in the prevention and treatment of parasites. They are common components of most canine heartworm preventives. At low doses, such as those used in heartworm prevention, ivermectin is safe even for dogs with the MDR1 mutation.
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.
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.
Recovery from ivermectin toxicity can vary from days to weeks. Prognosis depends on the dose ingested, the time it takes to receive care, and if the patient had concurrent factors, such as other medications or MDR1 gene mutation.
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.
Ivermectin is generally a safe, effective dewormer for dogs and is commonly used in low doses as a heartworm preventative and in higher doses to treat conditions such as mange. Some dogs, however, carry a genetic mutation (MDR1) that makes them more susceptible to toxicity from higher canine doses of this common drug.
– For most dogs signs of toxicosis may be seen at doses greater than 2 mg/kg (0.9 mg/lb). Dogs affected by genetic sensitivity can have toxicosis with as little as 0.1 mg/kg (0.04 mg/lb).
Dogs of some herding breeds and some mix-breed dogs can have a genetic mutation that makes them dangerously oversensitive to ivermectin, the active ingredient in some commonly used heartworm prevention medicines for dogs.
Border Collies are generally a healthy breed with an average life span of 12-15 years. Some can suffer from common health concerns like hip dysplasia, epilepsy, and hypothyroidism. Early diagnosis is the key to a long and happy life, so be sure to schedule routine checkups.
Tell Your Vet. The MDR1 genetic test offered by WSU will determine if your pet has the MDR1 mutation. For dogs and cats with the MDR1 mutation, common medications can be potentially deadly. Share the results with your veterinarian to let them know to avoid or adjust the dose of certain medications.
For years veterinarians simply avoided using ivermectin in herding breeds, but now there is a DNA test that can specifically identify dogs who are at risk for side effects from certain medications. Testing him early in life can prevent drug-related toxicity.
The FDA has not authorized or approved ivermectin for the treatment or prevention of COVID-19 in people or animals. Ivermectin has not been shown to be safe or effective for these indications.
Selamectin. Selamectin is another anti-parasite medication that is the main ingredient in certain flea, tick and heartworm preventative medications. Selamectin also kills ear mites and sarcoptic mange (scabies), according to veterinarian Dawn Ruben of the Pet Place website.
Dog owners are generally recommended to treat their dogs for worms once every 3 months for adult dogs.
At least every three months. Depending on your pet's lifestyle, more regular worming may need to be undertaken and it is recommended this be discussed with your vet if you are concerned.
Ivermectin is approved for use in dogs and cats for the prevention of dirofilariasis at oral doses of 0.006 and 0.024 mg/kg, respectively, once a month. Most dogs tolerate oral ivermectin dosages up to 2.5 mg/kg before clinical signs of toxicity occur.