# Heartworm Prevention - Ivermectin and MDR1



## RatherLoopy (6 mo ago)

My vet says I can give my dogs undiluted 0.1% Ivermectin solution orally at the rate of 1/10 ml per 10lbs, so my 100-lb Pyrenees would get one full ml/cc and my 40-lb mix would get 0.4 ml. Seems like extreme overkill to me, but an acquaintance in rescue agrees with that dosage.

My vet also says that I shouldn't treat my young collie mix (white feet, don't treat) and sure enough, I had him tested and he's confirmed to be carrying one MDR1 gene.

Whole Dog Journal (and others) (Dogs with the MDR1 Mutation: Drug Sensitivities - Whole Dog Journal) says that the low concentrations of Ivermectin in commercial prevention is safer than leaving affected dogs untreated.

Does anyone have any experience mixing 0.1% liquid Ivermectin at safe levels for MDR1 dogs?


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## parus (Apr 10, 2014)

Aren't there heartworm preventatives with something other than Ivermectin as the active ingredient, like Interceptor?


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## 3GSD4IPO (Jun 8, 2016)

Where do you live and how prevalent is heartworm infection in your area? Is your dog outside and frequently exposed to heart worm carrying pests?? There are areas if the US that have very little HW risk.


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## Lillith (Feb 16, 2016)

Yes, there are preventatives that do not contain Ivermectin. Ask your vet about them.


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## LeoRose (Aug 20, 2015)

There are several different preventatives without ivermectin. Some may or may not be ones that MDR-1 mutation dogs can take. One thing to consider is your dog's risk. If you are in the southern US, where you can pretty much assume any dog not on prevention has heartworm, then the benefits probably outweigh the risks. If you are in an area where the incidence of HW is low, then discussing the odds of not dosing your dog with your vet would be a good idea.


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## RatherLoopy (6 mo ago)

Thanks for the replies, all. I'm not looking for an alternative to Ivermectin but trying to learn how to mix 1% Ivermectin at safe levels for MDR1 dogs. I currently have five adult dogs, mostly stray/abandoned but a couple of seniors I took out of local shelters (who are also stray/abandoned, I suppose), and can no longer afford to buy commercial HW preventatives, so I'm moving to liquid Ivermectin. I'm in a rural part of central Texas and mosquitos & heartworms are prevalent here... no dog spends longer than a year or so outdoors without becoming HW-positive.

My thinking is that if commercial preventative can treat MDR1 dogs at safe levels, I should be able to mix liquid 1% Ivermectin at safe levels... I'm just trying to figure out how.


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## DaySleepers (Apr 9, 2011)

Giving advice for how to mix medication concentrations - even over the counter medications - is bordering on violating the forum rules on no medical advice. If your vet can't help you, it might be time to get a second opinion from a vet who can work out the correct dosage with you, or to call the manufacturer to see if they have dosing instructions. 

Also, make sure your dog has a negative HW test before you start treating if he's never been on preventative before. If he does have a heartworm load, introducing parasite treatments now may cause them to die off in large numbers and become obstructions in his heart.


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## 3GSD4IPO (Jun 8, 2016)

Anyone on a forum to advise you on dosing for a dog with MDR1 mutation would be remiss....


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