# Ivomec warning



## Christine Maddox (Mar 9, 2009)

IF YOU GIVE YOUR DOGS THE LIQUID IVOMEC, PLEASE READ THE FOLLOWING:
I took my female into Brittmoore Animal Clinic in Houston (very well respected) for a progesterone test. They used the same blood sample to run a heartworm check on her. I have been using Ivomec for over 30 years faithfully, each and every month, and have never had a dog come back with positive results. Well, my female has a mild case of heartworms. I was told by the vet at Brittmoore that they are seeing a lot of test/trial dogs (I am assuming this is due to the fact that so many of us with multiple dogs use it) that are coming back positive for heartworms. Cases are showing up from Mississippi to the Texas coast region. If you fall into this category, PLEASE have your dogs checked as soon as possible and change to another form of prevention. Positive cases are not showing up for dogs using Heartguard or Sentinel, just the liquid form of Ivomec. I now have to have my other 6 dogs tested.
Yes, it will cost more money each month to treat them with a prescription preventatives, but nothing compared to the expense of having to put your dog through the treatment (or worse)


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## Granddaddy (Mar 5, 2005)

Thanks for the info. Since Ivomec in numerous tests & years of application has proven effective as a heart worm preventative, I wonder if the issue is actually proper dosage?

Rather than a word of mouth pronouncement by a clinic, it would be a much more professional practice to publish the statistical data behind that opinion by those who claim that Ivomec liquid is not effective.


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## Julie R. (Jan 13, 2003)

Agree with what David D. said, above. Been hearing for several years that some dogs in Gulf Coast states mainly, have been getting heartworms even though regularly treated with ivermectin, the drug in ivomec and many other made-for-dogs heartworm preventatives. Sounds more like a strain of the parasite is developing a resistance to ivermectin more than treating w/Ivomec. I've used Ivomec for years, my dogs get it year round, but mosquitos are not bad in the area where I live and I do get my dogs tested annually.


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## rboudet (Jun 29, 2004)

How many days between the time you gave the last dose to when they did the test? If you dose on the 1st and test on the 30th, I have been told you can get a positive test.


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## Christine Maddox (Mar 9, 2009)

I told the vet at Brittmoore the dosage that I had been giving and his reply was that it was more than adequate. (Julie) Yes, there is a resistance to Ivomec in this area. 
(Rboudet) Given the fact that it takes approximately 6 months from the time of the infected mosquito bite to become a mature heartworm, the timing of when I gave the last dosage is of no consequence. There is already detection in the bloodstream which means there has to be an adult present. (though I do give on the first of each month and she was tested on the 25th)
(David) I am not a professional in this field so am not capable of publishing the exact data and was not offered such from the vet. I only wanted to pass along the word to others. I wish someone had passed it along to me.


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## BirdNMouth (Sep 16, 2008)

There has been ivermectin resistant heartworm in some areas for a while now. Most of the heartworm "breakers" have been on dogs treated with Heartguard & the other heartworm meds using Ivermectin. Changing your dogs from Ivomec to Heartguard is NOT going to keep your dog safer since it's the same drug in a much smaller quantity. Either look for a heartworm Med that uses a non ivermectin drug or possibly look at how You're storing your Ivomec. Ivomec is light & heat sensitive so should be stored in a dark container in the fridge. Check the experation date on the box. And regardless of what method you use, heartworm checks yearly are important. 
-Danielle


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## Mary Lynn Metras (Jul 6, 2010)

HEARTGARD® Plus (ivermectin/pyrantel)
contains Ivermectin so what would be the difference. I agree with Dave need to have stats on what you are saying. I believe I have heard my vet say it is an issue of when the medication is given. Sometimes people skip doses and your dog could get infected then. It is also a good idea to make sure if you use Ivermection it is stored correctly and you give the correct dosage as calculated by your vet. Always check with your vet!JMHO


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## EdA (May 13, 2003)

I would be happy to supply a synopsis of the most recent data presented at the American Heartworm Society meeting in 2013 if anyone is interested, there is inaccurate information circulating in the dog world. It will be later today or tomorrow for those interested.


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## Bridget Bodine (Mar 4, 2008)

I am interested , Doc. Thanks!


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## Dave Burton (Mar 22, 2006)

Interested as well. email address is [email protected] if that is the best way to send it. My understanding(may be wrong) is that the Ivomec will be out of their system after a couple weeks but when you give it the next month it will kill any young HW's that may be present therefore keeping them HW free. Before I go to Ark or La to hunt I always dose right before I go no matter when I gave it before.


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## yellow machine (Dec 7, 2005)

Mary Lynn Metras said:


> HEARTGARD® Plus (ivermectin/pyrantel)
> contains Ivermectin so what would be the difference. I agree with Dave need to have stats on what you are saying. I believe I have heard my vet say it is an issue of when the medication is given. Sometimes people skip doses and your dog could get infected then. It is also a good idea to make sure if you use Ivermection it is stored correctly and you give the correct dosage as calculated by your vet. Always check with your vet!JMHO


Stored in the house under normal house temps is what I have been told to do by the supplier. Is this correct?


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## suepuff (Aug 25, 2008)

Yes please Dr Ed.


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## Mary Lynn Metras (Jul 6, 2010)

yellow machine said:


> Stored in the house under normal house temps is what I have been told to do by the supplier. Is this correct?


 I believe light affects the contents.


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## Mary Lynn Metras (Jul 6, 2010)

EdA said:


> I would be happy to supply a synopsis of the most recent data presented at the American Heartworm Society meeting in 2013 if anyone is interested, there is inaccurate information circulating in the dog world. It will be later today or tomorrow for those interested.


 I am interested and thank you.


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## RJG (Feb 18, 2005)

I am interested and thank you Dr. Ed. I store mine in the fridge just in case - would like to know if it should be in a light blocking container. I use 1/10 of a cc per 10 lbs.


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## EdA (May 13, 2003)

Update on Canine Heartworm Prevention


1. All currently available heartworm preventatives are members of the same group known as macrocyclic lactomes which includes ivermectin (Heartgard), milbemycin (Sentinel & Trifexsis) salemectin (Revolution), and moxidectin (Advantage Multi and Proheart 6 injection). There are 20+ compounds in that group.
2. The macrocyclic lactomes kill the L3/L4 larvae in the tissue phase after inoculation of the larva by a mosquito bite.
3. To be effective these products must be administered every 30 days, beyond 40 days some larva may not be affected, the exception being the injectable form of moxidectin (Proheart 6.)


Heartworms Resistant to the class of drugs macrocyclic lactomes.


In 2007 +\- the FDA received an abnormal number of reports of lack of efficacy hereafter referred to as LOE. The vast majority of these reports were from the Mississippi delta in TN, AK, MS, and LA. Subsequently there has been much speculation about the possibility of a resistant strain of the canine heartworm Dirofilaria Immitis in that region. A number of scientific studies have ensued, from those here is what we currently know.


1. There does appear to be a genetically different strain of D. Immitis in those areas.
2. The affected area does not appear to have expanded beyond that area.
3. Of the reports of LOE an analysis of the medical records of those dogs reveals that 80% did not have sufficient product to administer to those dogs every 30 days.
4. 99% of the dogs in the affected area are protected by currently available products.
5. There is a genetically identifiable difference in the apparent D Immitis "resistant strain" however researchers currently think this strain is not as robust as the standard D. Immitis.
6. Resistance to one member of that class equals resistance to all members since they all have the same mode of action.


Current theory is that the resistant strain of D. Immitis may have resulted from the widespread use of the so called slow kill method of heartworm treatment in the indemic area.


No kill shelter programs have moved thousands of potentially heartworm infected dogs into areas of the country which previously have not had heartworm disease. Many of these dogs come from the gulf coast and the Carribean where heartworm disease is prevalent.


What can you do to protect your dog


1. Give label approved heartworm preventatives every 30 days year round no matter where you live.
2. If possible limit exposure to mosquitos with the use of screened or indoor kennels, mosquito traps, and/or mosquito repellents. Remember that mosquitos are most active from twilight until dawn.
3. Perform annual heartworm tests for adult dogs. The sooner heartworm infections are treated the less likely for complications or long term pulmonary artery damage.


Information is changing rapidly and what we know today could change tomorrow.


For more information on canine heartworm disease visit http://heartwormsociety.org


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## jeff t. (Jul 24, 2003)

Thanks Dr. Ed


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## Granddaddy (Mar 5, 2005)

Christine Maddox said:


> I told the vet at Brittmoore the dosage that I had been giving and his reply was that it was more than adequate. (Julie) Yes, there is a resistance to Ivomec in this area.
> (Rboudet) Given the fact that it takes approximately 6 months from the time of the infected mosquito bite to become a mature heartworm, the timing of when I gave the last dosage is of no consequence. There is already detection in the bloodstream which means there has to be an adult present. (though I do give on the first of each month and she was tested on the 25th)
> *(David) I am not a professional in this field so am not capable of publishing the exact data and was not offered such from the vet.* I only wanted to pass along the word to others. I wish someone had passed it along to me.


I meant the vet, not you. I appreciate you posting the info. I had a similar discussion with a drug rep last fall, who claimed that Heartguard was ineffective in the delta & that I should use his product. I asked for the data, he couldn't or wouldn't produce it, so I did a little investigation & found the data Ed posted. As it turned out the data didn't support his position but since Heartguard has been the supplier of choice for several years all the competitors were taking their shots. My question was much like several here who saw the inconsistency of saying Heartguard was ineffective but use my product that uses the same drug.


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## HuntinDawg (Jul 2, 2006)

Thank you Dr. Ed.

Here in Georgia there is no such thing as a time of day when mosquitoes are inactive. I have my yard sprayed for mosquitoes regularly during the prime season and it helps, but it is like shoveling crap against the tide.

The way our dogs move around, especially working dogs, I am surprised that the area wherein the resistant strain is found has not expanded.


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## EdA (May 13, 2003)

HuntinDawg said:


> The way our dogs move around, especially working dogs, I am surprised that the area wherein the resistant strain is found has not expanded.


It is somewhat surprising to those who have knowledge of vector borne diseases yet the area has remained fairly static so far which is the good news for most of us.


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## Lesa Cozens Dauphin (Sep 13, 2005)

Thank you, Dr. Ed!

lesa c


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## Christine Maddox (Mar 9, 2009)

Thank you Ed for your posting. 
I am in the process of changing Tease's AKC registration (actually sent in 2 weeks ago) and if she comes back negative on her HW test, still plan on doing the breeding Phil so much wanted.
I will keep in touch.


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## Billie (Sep 19, 2004)

EdA said:


> I would be happy to supply a synopsis of the most recent data presented at the American Heartworm Society meeting in 2013 if anyone is interested, there is inaccurate information circulating in the dog world. It will be later today or tomorrow for those interested.


Thank you- very interesting..


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## wayne anderson (Oct 16, 2007)

Thanks, Ed. I have used ivermectin forever with no problems, so this is reassuring.


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## dinaperugini (Jun 4, 2012)

Thank you Dr. Ed.


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## badbullgator (Dec 20, 2004)

Very interesting information Ed. Thank you


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## Sundown49 aka Otey B (Jan 3, 2003)

Thanks Dr. Ed. Good info as usual... a big thumbs up to you sir...


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## championretrievers (Feb 7, 2008)

I try to keep up-to-date on all the studies involved with heartworms. In studies we know the given dogs actually received the medication and received it all in the same manner. In the studies I have found all forms of heartworm treatment ( including injectable moxidectin) have failed except for the topical moxidectin(advantage multi). Not trying to stir up anything, but since I have my dogs on advantage multi I would like to know if anyone has found studies where advantage multi has failed or had resistance? I am not talking about articles that have no substantiation but actual scientific studies. In part, I am hoping it corrobates what I have found so far. But on the other hand, if I am overlooking some studies , I want to know also. Education is the key to prevention. 
For years we were told there was no resistance to heartworm products that were on the market. A variety of reasons were given why some dogs came down with heartworms that were on preventative. Now more recently, due to studies , resistance is finally being acknowledged. I hope these studies continue because they are the key to eventual prevention of heartworms and/or better treatment. 
Look forward to seeing if someone has the answer about the studies and advantage multi


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## marsh (Jun 27, 2013)

I live in Arkansas surrounded by rice fields which remain flooded most of the summer, mosquitoes are a problem. My 3yr old CBR was on heart guard year around and got heartworms. We test every six months. She went through the treatment and was heart worm free after a year. For the last four years I have been giving them the Ivemec liquid orally .1cc per 10lbs of body weight every month. In addition I have a 1/2 hp fan that blows through the kennels 24/7 from April to Oct. So far I have not been hit again, but I am always nervous now when we do the heartworm tests.


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## Jim Stevenson (Mar 18, 2010)

Thanks for the post Dr. Ed. I question your 6th point. Or the Heartworm Society's 6th point. 

All statins aren't created equal, so why are all macrocyclic lactomes? 40 mg and then 80 mg of pravastatin didn't budge my LDL but 40 mg of atorvastatin put a pretty good dent in it. 

I pretty much live in the epicenter of all of the heartworm problems. I know several kennels were giving heartguard (merial) on 1rst and interceptor (now sentinel novartis) on 15th and still had some positive tests. Those kennels didn't change anything except their preventatives to advantage multi (bayer). No more positive tests. I know that's anecdotal as is my LDL cholesterol level. Is there a scientific explanation for this?

Again, I'm skeptical of the American Heartworm Society's 6th point. They are Bayer, Elanco, Merial, Novartis, Zoetis, and Merck. 

I guess the AHS could be as indifferent to it's 'sponsors' as the United Nations is to it's main contributor, but I don't trust anything coming out of there either.


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## EdA (May 13, 2003)

copenhawgen said:


> Thanks for the post Dr. Ed. I question your 6th point. Or the Heartworm Society's 6th point.


I apologize for troubling you with this information, in the future I will avoid posting data based on science and leave things to conjecture, speculation, and anecdotal evidence.


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## Lady Duck Hunter (Jan 9, 2003)

EdA said:


> I apologize for troubling you with this information, in the future I will avoid posting data based on science and leave things to conjecture, speculation, and anecdotal evidence.


Lol

No, Ed, please continue to post the information that many of us wait to read. We appreciate your experience, education, and advice. Thanks for being here!


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## jeff t. (Jul 24, 2003)

copenhawgen said:


> Thanks for the post Dr. Ed. I question your 6th point. Or the Heartworm Society's 6th point.


What are your qualifications to challenge the heartworm society? 

Unbelievable


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## Jim Stevenson (Mar 18, 2010)

I'm not troubled. SKEPTICAL. Do a case study on the Council for Tobacco Research.

I do not need any qualifications to question the heartworm society. Likewise, I don't need any qualifications to question the Congressional Budget Offices's estimate of how much the Affordable Care Act will cost. Obama won the Nobel prize, does that mean that the only people qualified to criticize his policies are other Nobel prize winners?

Am I the only person who would be shocked if the AHS found that Advantage Multi works better on the resistant strain than the other preventatives? And then made those findings public knowledge? Willing suspension of disbelief.


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## Trykon (Oct 22, 2007)

No offense but I have seen this resistant strain with my own eyes. I train between 20-30 dogs at any given time. This particular dog had been on heart guard ever since he was young. While in my care he was on heart guard and ivomectin. I gave every dog ivomec on the 15th on top of what ever the owners supplied. This dog had been with me for 3 months at this time. We did a heartworm test and it came back positive. We pulled a sample of his blood and could see the live larva. My question is... If the dog received heart guard on the 1st and ivomec on the 15th. Test was done on the 18th. How is their live larva in the blood if the ivomec is doing its job.. For that matter the heart guard..... If it's doing its job their would be no larva in the blood especially with it being that close to the time given. 

Also he had double the dose of ivomec between heart guard and ivomec. 

I currently use pro heart 6 and have had no issues with it.


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## rds7015 (May 19, 2006)

Hello everyone, We have several problems here. Do we shoot the messenger? It was good info. Do we all agree with it no. Do I agree with it yes. Example, you all do not train the same way. I live in Brownsville,Tx and we have bugs year round. We also treat for them. Because I pay the vet for his advice I take it. Bugs get immune to the killing agent, from long time usage. I do not short change my hunting dog on her protection. She gets Heartgard Plus and Comfortis once a month for her protect.
Remember, there can be false positives Dr. Ed has had over 6000 post. Enough said
Good luck


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## Christine Maddox (Mar 9, 2009)

..here is an article about the problem

Article: Heartworm drug resistance: It's real - VIN

http://news.vin.com/VINNews.aspx?articleId=28284&callshare=1


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## Mary Lynn Metras (Jul 6, 2010)

EdA said:


> I apologize for troubling you with this information, in the future I will avoid posting data based on science and leave things to conjecture, speculation, and anecdotal evidence.


EDA I hope not! We appreciate your information. Thank you.


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## championretrievers (Feb 7, 2008)

This article given in the above post points out that the Bayer is "unaware of any published data showing a similar failure of moxidectin product applied to the skin". The CAPC confirmed this. "Topical moxidectin is thought to result in higher plasma levels than injectable moxidectin"-stated by CAPC parasitologist Little. Research supports a non-failure rate to-date on topical moxidectin aka Advantage Multi. Pretty impressive thus far


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