# Heartgard/ Triheart not working?



## julie allen (Dec 24, 2010)

Has anyone else heard of Tri heart and Heartgard not working anymore? I had 3 of my six test positive who have ALWAYS been on prevention, never a missed dose. Vet says it is just failing to work?? I now give the ivermectin orally.


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## Sara Waters (Oct 23, 2010)

I guess the development of resistance is probably bound to happen sooner or later. I deal with a lot of herbicide resistance in crop weeds and in sheep worms. As one of the world renowned gurus of resistance says - if you are on a good thing dont stick to it - rotate chemicals and always use the full dose.


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## David Frost (Mar 29, 2006)

there is an area that covers West AR, West TN and south through MS where dogs on hw preventative are testing positive. They aren't really sure why it's happening. From my understanding it's happening in about equal number regardless of the brand of preventative being used. Dogs I have working west of the TN River have been taking Heartguard on the first of the month and Advantage Plus on the (at the advice of my Vet) until they can figure out what in the world is going on. We also test semi-annual rather than the standard annual. I'm of the understanding a collaberative effort between Auburn and Va Tech is on-going to determine what is going on relative the hw problem.

dFrost


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## julie allen (Dec 24, 2010)

So I am wondering if it is really a resistance problem or not having enough of the drug in heartgard? The treatment has been outrageous for three large dogs, now paying for prevention that isn't working. I did try thr advantage multi, and fleas took over. Ugh.


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## Sara Waters (Oct 23, 2010)

julie allen said:


> So I am wondering if it is really a resistance problem or not having enough of the drug in heartgard? The treatment has been outrageous for three large dogs, now paying for prevention that isn't working. I did try thr advantage multi, and fleas took over. Ugh.


I dont think they know yet. It will be interesting to know what the study that David mentions turns up - see the link. 

I think they are looking into the possibility of resistance along with other factors that may be occurring.

http://www.heartwormsociety.org/AHS-Resistance-Article-A.pdf


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## Mara Jessup (Sep 7, 2010)

julie allen said:


> So I am wondering if it is really a resistance problem or not having enough of the drug in heartgard? The treatment has been outrageous for three large dogs, now paying for prevention that isn't working. I did try thr advantage multi, and fleas took over. Ugh.


 That is a good possibility. Since ivermectin is a relatively safe drug (unless you have a dog/breed with sensitivity issues) I'd ask your vet about giving a slightly higher dose.

Here is the summary from the annual HW symposium http://www.heartwormsociety.org/AHS-Executive-Summary.pdf

And here is a thread that pulls out the resistance information and breaks it down into something easier for most of us to read http://www.bordercollie.org/boards/...365492&hl=heartworm&fromsearch=1&#entry365492


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## Maren Bell Jones (Jun 7, 2006)

Hi Julie, if you bought the Heartgard/Triheart from your vet and they had a yearly heartworm test performed, most reputable companies will pay for at least some of the treatment. I'd call them (or have your vet call). 

Heartgard (Merial):

http://www.merial.com/ContactUs/NorthAmerica.aspx

Tri-heart (Intervet Schering-Plough):

http://www.triheartplus.com/contact.html


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## julie allen (Dec 24, 2010)

Thanks for the links. I am currently giving 1/10 of ml per 22 lbs of 1% ivermectin. Using comfortis for fleas. So far none of the people I have talked with that give the drug orally ( or I should say the injectable orally if that makes sense) have had a positive test. Yet comparing numbers not that many use the cattle type rather than heartgard. 
I use a country vet, who haven't always kept up with the purchase. Only if you are in for exams, if you just drop in they sell it and is not documented anywhere. They will NOW, of course.
My old mal has a severe case, and is having a time with the treatment. He has actually coughed up blood. Our farm borders a swamp, and mosquitos are impossible to deal with.


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## Denise Gatlin (Dec 28, 2009)

I've used oral Ivermectin for nearly 15 years with no positive HW tests yet. Use 1/10 cc per 10 lbs body weight hidden in peanut butter sandwich just toss it to each dog monthly. It has to be given yearly here as we have mosquitoes year round. We have had many LE k9s come up pos in my area over the past few years while on a variety ie Heartgard, Sintenel, etc. And a lot of dog training buddies have had their dogs come up pos. For me, this has worked. I always make sure the product has been kept cool and when I buy it, immediately put it in the fridge. So far, so good.


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## Mike Valente (Sep 14, 2010)

julie allen said:


> Thanks for the links. I am currently giving 1/10 of ml per 22 lbs of 1% ivermectin. Using comfortis for fleas. So far none of the people I have talked with that give the drug orally ( or I should say the injectable orally if that makes sense) have had a positive test. Yet comparing numbers not that many use the cattle type rather than heartgard.
> I use a country vet, who haven't always kept up with the purchase. Only if you are in for exams, if you just drop in they sell it and is not documented anywhere. They will NOW, of course.
> My old mal has a severe case, and is having a time with the treatment. He has actually coughed up blood. Our farm borders a swamp, and mosquitos are impossible to deal with.


 
The rule for dosage is generally .01cc per 10 pounds, Treatment kills whats there , there is no residual, so with mesq. that bad within 2 weeks they'll most likely test positive again. If you understand the life cycle it takes a few months for them to mature into adults so a strong dose monthly should take care of it. I'm betting the commercial crap wasn't strong enough based on how severe you have them in your area, stick with the liquid but increase the amount monthly.
Heres something to look into, (Grapefruitseed extract) its supposed to have good results with fleas also.
http://www.nutriteam.com/parasites.htm
http://www.dolforums.com.au/lofiversion/index.php/t137059.html


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## Connie Sutherland (Mar 27, 2006)

Sara Waters said:


> *I dont think they know yet.* It will be interesting to know what the study that David mentions turns up - see the link.
> 
> I think they are looking into the possibility of resistance along with other factors that may be occurring.
> 
> http://www.heartwormsociety.org/AHS-Resistance-Article-A.pdf


I don't think there is real solid info yet, either. I joined a service that emails me completed studies, etc., of failures of regular Heartgard, and the link Sara provides is pretty much the state of knowledge at the moment.

At this time, I would be getting my Heartgard from a vet or an online company that keeps the records and provides the guarantee (for treatment in case of failure).


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