Ivermectin toxicity in dogs

[Chickerdoodle13]

Friday morning my family woke up and found my dog unable to stand up and apparently blind so they rushed him to the vet. He's 9 years old and had been perfectly fine before hand and the vet was stumped. They ran bloodwork and x-rays and all that showed up was slight dehydration. The vet thought it was a tumor in the brain, but my dad turned down an MRI because it was about $3000. He kept asking if the symptoms could be caused by ingestion of ivermectin or thrush buster for horses, because he had used both the day before. The vet just kept saying neither of those things would cause blindness like that.

Well my dad looked up ivermectin toxicity in dogs and it turns out he is pretty much showing the exact same symptoms that ingestion could cause, especially in herding breeds (he's a cattle dog). One of our horses likes to spit the wormer out and we think Dalton might have licked it up before my dad could clean it. It had never been an issue before and the warning on the box is so small you can barely see it.

He seems to be getting better. I'm away at school, but my mom said today he was up walking, eating, and drinking. He still can't see and she said his pupils are very dilated. Most of the websites say there is a good chance he will get his sight back, but it may take two or three weeks. My dad has a call in to two dog eye specialists to see if there is anything else we might be able to do. I still don't know if we are out of the clear and it is very scary to think it could still be something else that we just aren't finding.

Does anyone have any experience with this sort of toxicity in dogs? I have never heard of it happening before, but the internet is ripe with stories about poisoning with ivermectin. For now my family is just keeping him on a leash when he is outside of the kitchen and he is doing well that way. It is very sad to see him like that though and we are hoping he will soon get his sight back. He is a really awesome dog and we've had him since he was a puppy.

 

[StormyMoon]

I am not an expert but this is my experience.
I wonder is Ivomec the same thing your talking about?

My vet gave it to one of my dogs a few years ago for demo mange but in small doses once every day for like a week. But she never had any symptoms from it.
I had to force it down her throat I can't imagine a dog willingly taking the stuff.

 

[rebelcowboysnb]

Its used to treat dogs for lots of things but in very small doses. Ivomec is a brand name of ivermectin.

It is easy to OD on it even with non sensitive dogs. Herding breeds on the other hand are very sensitive to it an normal doses will OD them.

 

[sheila3935]

never give ot let a dog that has any collie in them. here is a report about it
Problems may arise when higher doses, such as those used against skin mites, are employed but even then, side effects generally do not occur with any anti-mange doses of ivermectin except in animals with genetic sensitivity. Such individuals are usually Collies, Shetland sheepdogs, Australian shepherds, and Old English sheepdogs, though some individual animals that are not members of these sensitive breeds may also be prone to side effects. Very low test doses are often recommended to identify thes individuals regardless of their breed. Alternatively, a blood test is available to test for genetic sensitivity (see below).

Collies with ivermectin sensitivity have been found to have a mutant gene for what is called the "P-glycoprotein." The P-glycoprotein has been studied largely because overexpression of this protein (i.e. having more of it than normal) results poor function of chemotherapy drugs in the treatment of cancer. The P-glycoprotein appears to be involved in keeping drugs out of certain body tissues. Having excess P-glycoprotein keeps chemotherapy drugs from reaching the tumor. When it comes to ivermectin sensitivity the problem is the opposite: mutant or non-functional P-glycoprotein leads to failure to keep certain drugs out of the central nervous system, allowing them access to sensitive tissue. Ivermectin side effects stem from ivermectin entering the central nervous system.

Approximately 35% of Collies have a genetic mutation creating a non-functional P-glycoprotein. This allows for ivermectin doses that would normally be blocked from the central nervous system to gain access to it. Other herding breeds as listed above also have a tendency to express this mutation. There is now a test for P-glycoprotein mutation so that ivermectin sensitive dogs can be identified.

 

[Chickerdoodle13]

Thanks guys. Looks like it was ivermectin poisoning afterall. He is able to see a bit today and went to do his business outside by himself. He even tried to chase one of our cats when she ran past him this morning! (He loves chasing them out of the kitchen)

So far so good. If anything, hopefully this will serve as a warning to other dog owners! So many people have farm dogs AND horses. It is extremely easy to accidentally poison your dog without even knowing it. Now we know to keep him inside while worming and to clean up every little trace of it that the horses spit out.

My dad plans to call the company to let them know that this happened to our dog and to make a suggestion that the warning on the box should be larger. Who knows if it will make a difference, but it couldn't hurt to try.

 

[abluechipstock]

i give ivermectin to my dogs for heartworm preventative, i give the injectable 1% orally, the dose i use is 0.1ml per 10lbs, but with big dogs you don't go over 0.8ml, never use the horse paste because you can't dose it correctly, and don't use on any collie like breeds, it does cause neuro toxicity when over dosed, hope this helps

 

[WoodlandWoman]

I'm so glad your dog is getting better!

I have two thoughts on this. One, is that even a non-sensitive dog could have an overdose if the dose was large enough for a horse. The other, is that he could be more sensitive to it. You can now get dogs tested, to see if they have this sensitivity. I think the last time I checked it was around $60-$65. We used to have a collie mix. I don't know if it's an issue in cattle dogs. You might want to try to find out if it is an issue in cattle dogs. It's been awhile since I read which breeds it's an issue in, besides collies.

 

[tommboy1973]

Quote:
How often do you give it, once a month like the Heartgard? That's a great idea, HG is so expensive but Ivomec is fairly cheap!

 

[rebelcowboysnb]

Quote:
If you are treating more than just heartworm .1ml for 10 pounds.
Here is the actual doses levels in Heartguard when matched to 1% injectable. (found online)
10 lbs = .0027 cc or ml
20 lbs = .0055 cc or ml
30 lbs = .0082 cc or ml
40 lbs = .011 cc or ml
50 lbs = .013 cc or ml
60 lbs = .016 cc or ml
70 lbs = .019 cc or ml
80 lbs = .022 cc or ml
90 lbs = .025 cc or ml
100 lbs = .027 cc or ml

It takes very little to take care of just heartworm.

Yes, once a month for heartworm. Once a week for mange.

 

[Chickerdoodle13]

After seeing what ivermec did to my dog, I'd be very careful about using it in any herding breed or possible mix. My dog did not ingest a lot. It was just the tiny bit my horse must've spit out after getting wormed. Luckily it does not seem like it caused any lasting damage, but I thought for sure we were going to have to put him down Friday and I was a wreck!