Ivermectin v. Heartguard

Ivermectin is the active ingredient in Heartguard. 

Do you mean Interceptor?  Ivermectin IS Heartgard.  Interceptor is different, and of the two, it also covers whip worms.  I had to switch from ivermectin to Interceptor b/c a dog we pulled for a rescue had whip worms and pooped in my house and yard.

Heartguard has gotten so it fails very often and dogs are getting heartworm while on it. 

ivermectin IS the drug in HeartGuard but it's also the drug that herding dogs -- like collies, shelties, etc. -- can die from.  In order to keep marketing it to ALL dogs, they continued to diminish the amount of the drug amount in HeartGuard more and more and more in order to make it 'ok' for herders.

But at this point, it's not only become ineffective, but it's also suspected that it's causing heartworm to simply become unaffected (resistant) to it.

so Interceptor is thankfully becoming more popular. 

But this is why the huge rush to bring out other "preventives" that are systemic (like Revolution and ProMeris) -- despite their adverse reactions -- to give a more 'convenient' type of solution.  The problem is that since those are systemic, and keep the drug in the dog's system 24/7 all month long, the risk is there as well for it to allow heartworm to become resistant.  In fact, Revolution is being seen more and more to 'fail' and dogs actually become heartworm positive while on it.

I use Interceptor even tho none of my dogs are herders now, and I could use the farm strength ivermectin.  Interceptor is safer and does more things as said above.  It kills not only heartworm but whips and hooks (which are a huge problem in Florida as well). 

Interceptor and Heartgard are in the same class of drugs (avermectins) and act similiarly.  Interceptor is more broadly effective on digestive system worms than Heartgard.  The drug in Heartgard (ivermectin), at higher doses, can kill other classes of parasites such as mites and flukes.  Neither antihelmintic is effective against tapeworms. 

Some breeds have a risk of being overly sensitive to ivermectin.  Though the dose at which it is present in Heartgard is generally safe, if you have a breed in the risk group, or a dog with unknown origins, it's smart to test for the mutation which creates this hypersensitivity as it also affects the dog's reaction to some other fairly commonly used drugs.  These breeds include rough and smooth collies, Aussies, mini aussies, OES, shelties, English shepherds, and a couple of coated sighthound breeds that trace their ancestry to collie/sheltie outcrosses.

Conversely, there's some documented cases of sensitivity to Interceptor in Border Collies, so one isn't in the free and clear with the use of that drug.  I use ivermectin because I've had two dogs with sensitivity to milbemycin oxime.  I use a separate wormer on a three month schedule that is effective against both digestive tract worms and giardia.

In fact, Revolution is being seen more and more to 'fail' and dogs actually become heartworm positive while on it.

Interesting.  I hadn't heard that, but it is a fact that its agricultural cousin, Dectomax, flamed only briefly across the world of worming products and has since fallen into extreme disfavor.  Selamectin has a long half-life, meaning it wanes in the system very gradually.  This action selects for a resistant population in no time flat.

I looked it up and indeed selemectin was touted when it first came out, for its long half-life in companion animals as well (nine days in cats and eleven in dogs).

Moxidectin is the antihelminthic we in the agricultural world have been forced to turn to.  This is the drug that is in Proheart.  However, it has a half life of mere hours - thus my suspicion that the problems encountered in dogs are related to the carrier which maintains it in the system, rather than the drug itself.  Moxidectin does not require a carrier to slow its excretion in livestock, as their gi tracts are slower.

 as others have said ivermectin is the active ingredient in heartguard.... with my pack of 7 I use straight cattle and swine ivermectin in a 1% solution .... I put it on a small piece of bread and give it to the dogs that way. 

I have been using ivermectin this way for about 5 years now.... much less expensive and it is effective.  Then again I have retrievers which don't have a sensitivity to the medication

s
 

Shalva

 as others have said ivermectin is the active ingredient in heartguard.... with my pack of 7 I use straight cattle and swine ivermectin in a 1% solution .... I put it on a small piece of bread and give it to the dogs that way. 

I have been using ivermectin this way for about 5 years now.... much less expensive and it is effective.  Then again I have retrievers which don't have a sensitivity to the medication

s
 

That's what I used to do with Kenya, as does her breeder on all their dogs (and her DH is a vet).  I may switch back since it's so much cheaper than the Interceptor and my dog's fecals have tested negative for whips. 

brookcove

problems encountered in dogs are related to the carrier which maintains it in the system, rather than the drug itself.  Moxidectin does not require a carrier to slow its excretion in livestock, as their gi tracts are slower.

I may be oversimplifying this but my understanding is that the 'carrier' is a time-release mechanism which 'keeps' the moxidectin in the body.  It was unreliable in it's time-release (and honestly, such a thing is always going to be victim to the metabolism which is SOO individual and breed-related so I don't see how it's ever going to be 'reliable';) but that the problem with ProHeart primarily was that after the 2d shot particularly (and sometimes after successive ones) there was a serious build-up in the body so when the next shot was administered there was 'overdose' in the body.  So yeah, it's a problem with the 'carrier' in tha the drug is forced to stay in the body and stay active. 

but I don't like to see anything systemic used.  Shoot -- I won't even use the "one a day" milk thistle -- I don't like NUFFIN that is 'time-release' in me or the dog! LOL

Yes, that is exactly what I meant.  I believe it's a problem with the use of the carrier.