I know the collie breeds can't have ivermectin and I remember hearing that Australian Shepherds can't either. So, is it dogs with the merle gene? I'm asking because I want to start my daschund on ivermectin heartworm preventative, but he is a double dapple. The dapple gene is the same thing as merle in collies and aussies. I don't want to take any chances with him. I know there are a couple of products that don't contain ivermectin, but they aren't as effective and atleast one of them causes sickness in alot of dogs.
stumbled upon this OP... so I'm not the best to answer (not a dog breeder) but my brindle boxer, fawn boxer, and short haired JRT all are fine (and I probrably overdose them a bit).... they are all papered purebreds...... hope that helps you. If not... sorry! LOL!
Its a gene that as far as I know is not linked to any known visible traits. It seems to be a gene that many herding breeds can have in common. There is a test for that gene but I dont think you can say 100% one way or the other by breed. My understanding, most dogs to fine at the dosing level for heart-worm. Its when you step up to the level people dose for other things that bad things can happen
Even our Austrailan Shepherd was always fine with the dosage of Ivermectin that is in heartworm prevention. We even talked to a couple vets about it and was told not to worry.
the intolerance is more common in some breeds than others (Collies for example) but any dog can have a reaction to it. http://beingstray.com/dogs/ivermectin-poisoning-parasite-prevention-drugs-dogs/ is a good source of info on the reaction
It doesn't have anything to do with the merle gene. If you are worried, there is a genetic screening test to tell if your dog has the gene that allows Ivermectin to pass through the blood brain barrier.
Some dog breeds are more sensitive to certain drugs than other breeds. Collies and related breeds, for instance, can have adverse reactions to drugs such as ivermectin and loperamide (Imodium). Drug sensitivities result from a mutation in the multi-drug resistance gene (MDR1). This gene encodes a protein, P-glycoprotein that is responsible for pumping many drugs and other toxins out of the brain. Dogs with the mutant gene cannot pump some drugs out of the brain as a normal dog would, which may result in abnormal neurologic signs. The result may be an illness requiring an extended hospital stay - or even death. Most Commonly Affected Breeds Australian Shepherd Australian Shepherd (Mini) Collie Long-haired Whippet McNab Silken Windhound
