Heartworm Preventatives

[Do No Harm]

I have been advised by a US source in the past few days, of information that was offered by a renowned Veterinary Hematologist and Researcher to those who attended a Seminar at which that veterinarian spoke. The information concerns Heartworm preventative medications.

This veterinarian recommended the DAILY heartworm preventative over the monthly ones because "It is the only one that doesn't have death as a possible side effect".

The daily heartworm preventative may be at risk of ceasing production with more consumers prefering the convenience and taste appeal of the monthly variety - although surely it is just as easy to add the medication daily when feeding a dog?!

The daily heartworm preventative is Dimmitrol (Diethyl Carbamazine) and it is made at MavLab. Their website is : http://www.mavlab.com.au/

Members of this forum might like to include consideration of this option when making an Informed Decision about the preventative health care of their dog/s.

[petaj]

DEC does have a wide safety margin for toxicity, but if dogs have circulating microfilariae and DEC is administered it is possible for for them to develop hypovolaemic shock. Dangers are possible with any drug, especially since these studies would probably only cover correct administration (ie after veterinary tests for microfilariae), which may not be the case as the tablets can be acquired from a supermarket without any advice being offered.

I am not trying to sell one method over another, as I have not researched the dangers of monthly dose forms and nothing of the sort has been mentioned during my parasitology course. I just think each person has to decide based on their lifestyle which will give the best overall protection. Obviously many people here are dog enthusiasts and will take the responsibility to ensure that the tablets are given daily (even if left for carers to do during a vacation, etc). However not all people that choose to own pets are this responsible or fully understand the implications of skipping treatments, etc. In these cases monthly and other treatment options may be the best option for the dog's welfare as it ensures a higher likelihood that they will not become afflicted with the disease. I also would have thought the relative affordability of daily treatments would make this option appealing and so it would still have a consumer niche, but it is bitter as a syrup and not all are capable of administering tablets to their dogs.

As I said before, I have not researched the reports of the dangers, nor has it been raised as a concern in my vet school, but the event (eg death) only has to occur once in one patient for it to be listed as a possible side effect. This may or may not include any unique individual reactions. Now this may be enough to convince anyone (for the obvious reason that they love their dog) that dosage forms other than daily are just not worth the risk, but on a wider public scale there are many factors that would influence choice of dosage form, not the least of which being owner compliance to proper administration.

I do agree that it would be a pity for any heartworm preventative options to be removed from the market, because the more opions that are made available hopefully corresponds to the likelihood that an owner will find an option suitable for them. However all treatment forms have their merits and downfalls, and in my opinion there probably isn't one option that is more responsible than another.

I am not saying that this is what you were trying to imply, and I think you are right that this treatment form is one which is valid for consideration. I just wanted to offer the information that I was aware of and some possible reasons that people choose the options they do, that may not be just for convenience.

[labsrule]

So where does this leave the Annual Heartworm Injection insofar as being a "safe" option as this is the option I use?

[morgan]

So where does this leave the Annual Heartworm Injection insofar as being a "safe" option as this is the option I use?

Who considers it to be safe?

My vet stopped using it well over a year ago because of the incidence of auto immune hemolytic anemia - he said that statistically it might have been small, but try telling that to the owners of the affected dogs!

[Nadia]

Proheart S12 is not reccomended here either, my Vet simply will not reccomend it.

One has to wonder when we are going to stop bombarding our dogs bodies with so many drugs and chemicals, and over processed foods.

Much is said about the inbreeding and the purebreeds being unhealthier etc etc. How about we stop and look at the crap we are subjecting the animals too over generations.

It is no wonder that many have immune issues.

[Missymoo]

Interesting topic..as I just bought a cheaper version of Heartworm prevenitive of the net..then I read the bottle when I got it and saw it was Diethyl Carbamazine, which I had never heard of. So I googled it and saw it was used for humans (?) and mentioned nothing of heartworm prevenative!

As the bottle at the top say "Adverse reactions may occour when administering this product to dogs..." I decided not to use it at all...

Id rather be well informed then confused!

[Nadia]

An adverse reaction is possible with ANY chemical or drug.

DEC is not safe for animals with Heartworm. The dog must be clear of Heartworm being commencing use with this and many other HW preventatives.

[Do No Harm]

So where does this leave the Annual Heartworm Injection insofar as being a "safe" option as this is the option I use?

The annual Heartworm preventative injection used in Australia is the Proheart SR 12 (SR 12 = slow release being active for 12 months). The active ingredient in Proheart is Moxidectin. The Proheart 12 contains three times the amount of Moxidectin than the Proheart 6 (slow release and active for 6 months). Both are made by Fort Dodge, the animal health division of the pharmaceutical company Wyeth.

Proheart 6 was withdrawn from the US market following pressure placed on Fort Dodge by the FDA. This was because of the high number of serious side effects from using the product. Indeed, there were many deaths!

Do a Google search on 'Proheart' and or 'Moxidectin'. Aside from those sites in which individuals or groups of aggrieved owners share their horrific experiences, there are copies of official letters from the FDA and copies of letters sent to veterinarians by the manufacturer (Fort Dodge). The Australian regulator of veterinary medicines here has adopted a 'watch in brief' approach while knowing the controversial history of the product.

[Buster's Mum]

I am a shiftworker so am never home at the same time every day so daily tablets are out for this reason.

My first dog got the yearly needle because I thought it was a good idea. I had not joined DOL at the time, was new to dog ownership and went by the recommendation of the vet (not the one I go to now). Buster got a lump the size of a 50c piece where the needle went in that went rock hard. It gradually got smaller until it eventually went away but it made me wonder if the yearly needle was the wrong choice so I started doing some research.

My vet assures me that the level of chemicals in the monthly tablet is very small and as far as I am concerned much safer than risking my dogs getting heartworm. She will not give the yearly injection as she feels the risks are not worth it.

Edited May 3, 2006 by Buster's Mum

[Hazz]

I would not use the yearly injection. I use a monthly tablet.

[labsrule]

Thanks everyone for your input and info on my query in this thread about the annual heartworm injection (Proheart SR 12 ) being a "safe" option.

I thought SR12 was a safe option as it was recommended to me by my vet and I did ask him at the time if there could be any adverse reaction to it and how it worked as I was concerned about it being able to provide 12months protection. I am paranoid about heartworm as one of my friends lost their dog to heartworm a few years back thru not treating their dog consistently for heartworm. My vet advised me that he was not aware of any problems with SR12, so I went ahead with it, after all you should be able to trust your vet's advice and most of us do

Prior to starting my dog on this, he and my previous dogs were on daily heartworm tablets as I found it easier to remember the daily as opposed to monthly when it was introduced. Anyway after doing some research last night after Nadia's response included the correct name Proheart S12, methinks I will no longer continue with this annual treatment and revert back to daily's in October when the 12months expire. At least during our two year stint in NZ (returned to OZ in Oct 05), my boy did get to have a reprieve from any heartworm treatment as there is no heartworm in NZ

I am also going to take this issue up with my Vet when next I visit armed with printouts of the info I have found on the internet and no, he won't be able to persuade me to reconsider DOL contains such a wealth of information and I am learning so much from the numerous postings.

[fido666]

Collie breeds can have a very adverse reaction to some of the monthly heartworm preventatives (mostly the mectin based ones). There is no way to know if your Collie, Border Collie, Sheltie, or Aussie has this sensitivity without a genetic test. A lot of Collie people will only use the daily ones for this reason. I have used Heartguard + on my Collies in the past with no apparent ill effects. My vet assures me the dose is low enough to not cause any problems, but now I'm not sure what to use .

Cheers,

Corine

[Ons]

I asked my vet about Proheart 12 just a couple of weeks ago when Onslow was due. She said it was safe for golden retrievers but not for collies, borders, shetland sheepdogs becuase they are sensitive to one of the ingredients.

However on another Forum I am on one of the golden retreivers died a horrible death from Proheart 6 (in the States).

I let Ons. have the injection but I think that I will keep Matilda-Rose on the monthly tablets and then next year put Ons. on them.

[Do No Harm]

I asked my vet about Proheart 12 just a couple of weeks ago when Onslow was due. She said it was safe for golden retrievers but not for collies, borders, shetland sheepdogs becuase they are sensitive to one of the ingredients.

I believe your vet is mistaken.

Specifically, she appears to be confusing Proheart (active ingredient is Moxidectin) which is the yearly injection, with Heartgard (active ingredient is Ivermectin) which is one of the monthly chewable tablets.

Collies and herding breeds are know to have a gene (although not all individuals do) which renders them unable to tolerate Ivermectin. Ivermectin can cause death in these susceptible dogs.

Gosh, I do wish veterinarians got their facts right!

Edited May 5, 2006 by Blackfoot

[petaj]

Just had a chat with a vet that seemed pretty on the ball. Apparently Proheart 6 in America has a different slow-release mechanism than the Proheart 12 used in Australia (despite being from the same company), and that no ill effects have been reported to the control board in Australia. 500 deaths in the US (albeit out of millions of dogs), and it is yet to be seen if the Australian version is truly safer or if it just hasn't been administered to such vast number of dogs to gauge similar reactions. He feels safe using it on his dogs.

[fido666]

I believe your vet is mistaken.

Specifically, she appears to be confusing Proheart (active ingredient is Moxidectin) which is the yearly injection, with Heartgard (active ingredient is Ivermectin) which is one of the monthly chewable tablets.

Collies and herding breeds are know to have a gene (although not all individuals do) which renders them unable to tolerate Ivermectin. Ivermectin can cause death in these susceptible dogs.

Gosh, I do wish veterinarians got their facts right!

Hi Blackfoot,

I'm afraid that Moxidectin is also implicated in the MDR1 drug sensitivity which affects Collies and related breeds, the list includes:-

-IVERMECTIN (also sold under the product name of Ivomec®)

-MOXIDECTIN (also sold under the product name of Cydectin®)

-MILBEMYCIN OXIME

-SELAMECTIN

-NEMADECTIN

-ABAMECTIN

-DORAMECTIN (mutation of S. avermitilis)

There are more, if anyone wants the full list PM or email me.

Cheers,

Corine

Edited May 6, 2006 by fido666

[Nadia]

In 2003 there were 90 reports of adverse reactions to Proheart S12 to the Australian Pesticides and Veterinary Medicines Authority, including deaths.

[mavmon]

Blackfoot Posted 5th May 2006 - 01:31 PM

Collies and herding breeds are know to have a gene (although not all individuals do) which renders them unable to tolerate Ivermectin. Ivermectin can cause death in these susceptible dogs.

Moxidectin & Ivermectin are very close relatives, many others too - as fido666 posted.

It is a mutant gene which leaves some dogs susceptible to undesirable & possibly fatal effects from certain drugs (not only "mectin" drugs).

These dogs do not have the MDR1 gene that produces the protein P-glycoprotein (P-gp).

When P-gp is present & functional the drug cannot remain in the brain – but when it is absent the drug penetrates the brain & stays there setting in motion the circumstances for toxic reaction.

Because the required gene (MDR1) is not there to “block” these drugs from entering the brain blood flow this then sets off a chain reaction of central nervous system dysfunction. Severely affected dogs can lapse into coma and death, usually due to respiratory arrest.

Not just Collies affected either.

And Ivermectin & Moxidectin are designed to absorb into the body fat of the subject. It is also designed to last for approx 1 month ..... not something I am prepared to put into any of my dogs (regardless of breed) in any dosage.

[InspectorRex]

German Shepherds, Aus Kelpies and Aus Cattle Dogs are also known to affected by the MDR1 gene. Both the ACD and Keplie are descendants of the Collie.

If in doubt have the DNA test doen through Genetic Science Services, around $65 but wll worth it. Even if I had one of the "affected" breeds andn the DNA was Clear I still would not use Ivermectin, Revoltion, proheart etc etc

I have found the only heartworm preventative that has been safe with my Rough collies to be either Interceptor Spectrum or Sentinel Spectrum. Sentinel Spectrum is also an allwormer, including hydatid tapeworms, so I just note the calender for the same date each month to give.

I also buy it from priceslesspets.com.au, a hell of a lot cheaper than the Vets etc

[fido666]

Thanks for posting that extra info Mavmon . My vet once was about to give my male Collie the Proheart yearly injection when I stopped him. I don't think he believed me at first but went off and did some Internet searching, I can't beleive he didn't seem to know about the MDR1 gene, he seemed to think it was only a problem when the original Ivermectin used in cattle was first given to dogs as a heartworm preventative.

Cheers,

Corine