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First off, if you don't know what MDR1 is, it's a mutation that's common in collies and several other herding breeds. It basically means there's an issue with the blood-brain barrier that makes it so certain medications can cause severe neurological reactions (and quite often death) in dogs with the mutation.

I did a lot of research before choosing a breeder, and part of why I chose my breeder is because one of the major things she breeds for beyond the standard is MDR1 normal/normal, meaning the dogs don't have the mutation and that they are not carriers (as some claim that carrier dogs sometimes have slight issues with the problem medications).

You can get more detailed information on MDR1 here: https://vcpl.vetmed.wsu.edu/vcpl-home

ANYWAY.

I didn't tell my vet that my dog was MDR1 normal/normal. The question never came up. She gave me some flea/tick treatment as well as some wormer. And, hey, the wormer happened to be Heartgard, which includes ivermectin, which is like the number one no-no drug in regards to MDR1.

Luckily, I know about MDR1, and again, luckily, if I didn't, my dog is normal/normal, so I can give her Heartgard. But this makes me really worried about any dogs that might come in who might have the MDR1 mutation.

So, to get to my question: Would it be appropriate for me to take an information sheet to my vet to let her know about MDR1?

I just... I would think vets would be aware of this? But since she just gave me Heartgard with no concern whatsoever, I'm not sure. She's super nice, they were amazing, and their practice has gotten awards and they are members of the AAHA. I'm just worried that if I give her the information she'll think I'm ... I dunno. Trying to be a jerk? Acting like I know more? I'm not sure.

What do you guys think? Should I take MDR1 information to my vet, even though my dog is normal and it doesn't actually affect her?
 

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Well, even MRD1 dogs won't always react to ivermectin, particularly in heartworm medication as the dose is so low. I'm not totally surprised she didn't say anything, since to my knowledge, heartworm medication does not cause any reaction in MRD1 dogs. Really you would need to look out for large dose formulations, usually in worming products for livestock (don't let your dog eat horse poop!)

If you really wanted to you could say something like "Oh, my breeder was talking to me about how my dog MRD normal/normal, will that have any bearing on her medications?" Then just act dumb for a minute. :p
 
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Oh, interesting! I had heard so much about people having bad reactions to even just a regular Heartgard dose. Thanks!
 

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@Gnostic Dog - Truer words were never spoken. Still on my hunt for a vet that won't bite my head off at feeding raw.
 
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Ask your vet about it. A good vet will gladly answer your questions and if your vet is not aware you may help someone else's dog by asking a simple question. Ivermectine is not the only medication that can cause issues. @Shandula too bad you are not close the vet I work for feeds his dogs raw and encourages clients who's dogs have certain health issues to feed raw as well. ;)
 

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Problem Drugs from that same site you linked(i recently wrote an article about this)

"While the dose of ivermectin used to prevent heartworm infection is SAFE in dogs with the mutation (6 micrograms per kilogram), higher doses, such as those used for treating mange (300-600 micrograms per kilogram) will cause neurological toxicity in dogs that are homozygous for the MDR1 mutation (MDR1 mutant/mutant) and can cause toxicity in dogs that are heterozygous for the mutation (MDR1 mutant/normal). "
 

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Yep, I find it interesting that there are a variety of medications that are a problem. It's just a really fascinating mutation, outside of the fact that it causes so many problems.
 

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Realistically it causes very few problems in practice. Most veterinarians rarely if ever use Ivermectin or the other avermectins in large doses on suspect breeds, or at all usually, and few use the cancer drugs listed as problematic, or Loperamide (not too effective). So if the 'problem drugs' are not being used at 'problem doses' it matters little to a veterinarian which dogs have the mutation or not. Most vets are very nervous about the suspect breeds and avermectins already (has been pounded into our heads for decades now), though as mentioned, drugs such as Heartgard use such infinitesimal doses the dangers are nonexistent.

I have worked in rescue for a long time and have had to use larger doses of Ivermectin in many dogs with chronic or recurrent Demodectic mange, but rarely does that seem to happen in a collie, Aussie, etc... Seems these immunosuppressed dogs usually are chihuahuas or pit bulls (which make up about 90% of all rescue dogs in my area)... but when it does occur in a suspect breed, then THAT is when testing for the mutation becomes an issue... problem is the cost of the test is usually prohibitive for the owners of these dogs as they are already on shoe-string budgets, so we end up simply choosing a different treatment option for these dogs (not as effective, but at least less dangerous). So far, in the 30 years in practice, have yet to have a single issue with MDR1.
 

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This is really good to know, I've got some vet pathologist friends and they warned me off ivermectin. I think they see all the rare and unusual reactions to things so they've been advising me based on extreme cases.
 

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I would mention it to your vet but not expect them to remember! I have a mutant/mutant rescue collie. I'm careful about when I give her heartworm medicine to her. I don't schedule her vaccines or dentals right around the same time (just to be safe) and always remind the vet that she has issues with immodium and acepromazine. She's never had an issue with anything and hopefully never will.
 
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