# anyone do doxycycline + ivermectin heartworm treatment?



## MagicSmoker (Sep 16, 2014)

I just found out that Lucy, a 3.5 year old black Lab mix I adopted in August of 2014, is heartworm positive. She has been on heartworm prevention every month since I adopted her, but I changed from Trifexis to Heartgard last November because she was developing an increasingly severe aversion to the Trifexis. I suspect that she did not get a full dose of the Trifexis last October, despite that I went through 4 pills to get what I thought (hoped) was a full dose down her.

My current vet recommends doing the 3 injection melarsomine (Immiticide) treatment, but I am not too pleased with him for a couple of mistakes made lately, and for seriously over-treating Lucy in general (e.g. - it just cost me $455 to find out she has heartworms after I brought her in for having a mild, intermittent cough, reduced appetite, and vomiting on the sofa... yet again [she has food and environmental allergies, though, so I assumed one of these was the cause]). Furthermore, a friend of mine took in a stray dog off the street that had heartworms and she said the treatment damn near killed the dog (had to rush him to the emergency vet because he started coughing up blood).

So I did some research and found a paper in a veterinary medical journal describing an alternate heartworm treatment protocol that takes 34 weeks but which is similar in effectiveness to melarsomine:

6mcg/kg of ivermectin by mouth weekly
10mg/kg of doxycycline by mouth daily for weeks 0-6; 10-12; 16-18; 22-26; 28-34

The advantages to this protocol are that the worms are killed more slowly than the melarsomine protocol, so there is a much lower risk of pulmonary embolism (ie - coughing up blood), but much more quickly than the ivermectin-only protocol (which takes 2+ years to kill the adults, all the while still damaging the heart). It is also somewhat less expensive, but that is a secondary consideration (Lucy has been an expensive dog already: I've spent over $5000 in vet bills in the 1.5 years I've had her). 

This treatment protocol doesn't seem to be terribly popular, though. I intend to call a few more vets next week, but my current vet didn't even know about it, and I'm not sure yet if that is more a reflection on him, or the protocol. In the meantime, I posted here to hopefully get some comments from others who tried or at least considered this protocol.

Thanks!


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## mrsserena (Nov 9, 2015)

Do you know how long she has had heartworm? If it's only a few months, the worms aren't likely very many or very large, so the treatment won't be that dangerous.

My guess is she had heartworm when you got her, and has had it for a while. That means her worms are mature adults, so the heartworm medicine you are giving her isn't enough to kill them. If so, I think the slow kill method you found is a good idea.


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## Willowy (Dec 10, 2007)

It's used frequently by Southern rescues who can't afford to do the standard treatment on every heartworm+ dog. So try calling a few rescues to ask about it, see what vet they use, how they recommend doing it, etc. It's sometimes called the slow kill method so they know what you're talking about.


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## MagicSmoker (Sep 16, 2014)

Thanks for the replies, and the suggestion to check with rescue groups is a good one. The one that immediately came to mind is the Humane Society, so I called my local one and they said they only do the "fast" and "slow" treatments (but did not define the "slow" treatment...), and that I would have to see one of their vets for more info than that. The earliest appointment is 4-24, or I can take my chances in the gladiator's arena (aka, the walk-in waiting room) tomorrow morning at 8:30AM.

As for how long Lucy has had heartworms, she tested negative on 11-30-2015, and from what I understand this test only reacts to the adult worms which take 6 months to mature. So, worst case her infection is 10 months old (ie - the worms were 5.5 months old on 11-30-2015).

Meanwhile, I also pressed my current vet for more details on their treatment. The cost would be "around" $1200 and the specific protocol is:

1) pretreat with prednisone (20mg/2x per day*) and doxycycline (2x100mg/twice per day) for 2 weeks
2) first injection of melarsomine with 4 hours of observation at the vet then go home
3) restrict activity for next 6-8 weeks
4) give pred/doxy for 2 weeks prior to 2nd injection 
4) give 2nd injection (dog must stay in hospital)
4) give 3rd injection 48 hours after the 2nd (dog can go home)

Seems like some minor tweaks, all things considered, and my vet all but guaranteed this protocol was very safe in young dogs without advanced disease, so I don't feel quite so apprehensive about it, but I am still going to check with some other vets just to be sure.

* - the usual tapering schedule (2x/day; 1x/day; every other day) was not specified, which is pretty much a no-no.


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## sandgrubber (May 21, 2014)

That looks like a good article (in the link in the OP's post). Have you showed it to your vet? 
The Heartworm Society is down on slow kill, but they receive a lot of funding from pharmaceuticals with a vested interest in the more expensive treatment. It's likely that their position has found its way into vet school texts, and the alternatives are not much discussed.
Talking to shelters seems like a good suggestion.


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## lzrddr (Feb 3, 2015)

You probably won't qualify since you used two different products, but if your pet tests negative before you start a heart worm preventative, and later ends up testing positive, often the company will help with the costs of treatment. You should still report it to them (both, I guess).


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## Fergusmom (Apr 12, 2015)

Barclay just finished heartworm treatment. His vet was only willing to do the staged-kill (3 injections), which she said is the safest method. The cost was about the same as what your vet estimate. 

He had adult worms and the microfilariae. Similar to you, he was negative when I adopted him, and was on preventative up until his diagnosis. I agree with Izddr, report it to the companies, they may possibly assist with the costs. It doesn't hurt to ask.


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## MagicSmoker (Sep 16, 2014)

I've called several more vets today and all of them only do the 3 shots of melarsomine (Immiticide) treatment and none of them have heard of the doxy/IVM protocol so I am sticking with the devil I know, so to speak. 

@lzrddr - Lucy has been to the vet a lot since I adopted her, so she has had 3 HW tests in the last year - 6-03-15 [neg]; 11-30-15 [neg] and 4-14-16 [pos]. Given what I understand about the HW life cycle it seems all but certain she got them while still on the Trifexis. 

@Fergusmom - How did Barclay do during the treatment? I am particularly interested in how you managed the activity restriction, as Lucy hates being crated or being left home alone for more than about 20-30 minutes (I either take her with me or drop her off at doggie day care - the latter option is clearly out of the question for now).


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## Fergusmom (Apr 12, 2015)

Barclay went through the first injection very well- He was sent home with tramadol, which he did not need after day 2. After about a month and a half he got the next round. With the second and third injections he was whiney and exhibited more pain, so I had to give him the tramadol for a bit longer 4 days. He had one incident of vomiting after the third injection. 

He is almost through tapering off predisolone. Being on prednisone was actually what worried me the most, having excessive urination and accidents. He did very well however- he had only one accident which was my fault for not seeing the signs that he had a full bladder.

He is 2.5, so a young guy, but slightly less active than my other dog. I mostly have to keep the other dog from riling him up. I buy huge bully sticks- the foot-long ones to keep them both occupied. Barclay has to spend a lot of time in the crate, which he hates, but oh well. Someone here on the board gave me some good suggestions for keeping him supplied with frozen kongs too, to keep him busy.

Edited to add, he goes to daycare once a week, but right now he has one-on-one play time with the staff, instead of being with the other dogs.


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## moluno (Apr 29, 2009)

3-4 weeks? I don't think that's right. I adopted a senior dog that was HW+. The rescue had started her on the slow-kill method (doxy + Heartgard), so I continued it when I adopted her. It was 2 years before she tested negative. 

For a young dog I would do Immiticide. As long as there are adult worms, they are causing damage. The less amount of time they are there, the better IMO.


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## MagicSmoker (Sep 16, 2014)

@Fergusmom - sounds like the treatment wasn't too bad, all things considered. I really appreciate you taking the time to post about it! 

@moluno - the doxy+IVM treatment is supposed to take 34 weeks, not 3-4 weeks...  I understand that the adult worms cause damage to the heart, but I also understand that when those worms are killed fragments of them will clog up vessels in the lungs, leading to damage there. The slower the adult worms die off the less likely there will be lung damage. Achieving a better balance between heart and lung damage is one of the main reasons the Immiticide protocol shifted from 2 injections 24 hours apart to 3 injections with 1 month or longer in between the 1st and 2nd (with the 3rd 24 hours after the 2nd).

At any rate, Lucy has begun taking the doxy with no ill effects and will get her 1st Immiticide injection on May 2. I'll update this thread as things happen.


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## Fergusmom (Apr 12, 2015)

Specifically it's the danger of pulmonary embolism from worm fragments in the arteries. That is also the reason for the prednisone.


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## sandgrubber (May 21, 2014)

Fergusmom said:


> Specifically it's the danger of pulmonary embolism from worm fragments in the arteries. That is also the reason for the prednisone.


I thought pulmonary embolism was only possible in the advanced stages of the disease. If this dog tested clear six months ago, does she even have adult worms? Certainly not a lot of them.


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## Fergusmom (Apr 12, 2015)

Sandgrubber,
Yes, the risk is highest with more worms.

From the Heartworm Society guidelines https://heartwormsociety.org/images/pdf/2014-AHS-Canine-Guidelines.pdf



> The greater the number of heartworms killed during an adulticide treatment, the more significant the potential for obstructive and in ammatory pathology (Venco et al, 2004). Unfortunately, no test (or combination of tests) is available to accurately determine the number of heartworms present. Whether carrying low or high worm burdens, infected dogs can be clinically asymptomatic and have minimal radiographic changes.


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## moluno (Apr 29, 2009)

sandgrubber said:


> I thought pulmonary embolism was only possible in the advanced stages of the disease. If this dog tested clear six months ago, does she even have adult worms? Certainly not a lot of them.


 Yes she'd have to have adult worms, the test only picks up antigens from adult female worms


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## MagicSmoker (Sep 16, 2014)

Quick update: I talked to a couple of rescue organizations and both of them have used the doxy+IVM protocol in the past, but felt the Immiticide protocol was more effective and, of course, a lot quicker. One further explained that the addition of giving the dogs prednisone before the first Immiticide injection has greatly reduced the complications from dead worm fragments and made this protocol almost as safe as the "slow kill" doxy+IVM, and since that is one of my primary concerns I decided to go with Immiticide after all.

Next update will be after Lucy starts the treatment, which will likely be tomorrow. And special thanks to sandgrubber for the helpful PMs with more info on the doxy+IVM protocol, as well as some vets that use it!


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## sandgrubber (May 21, 2014)

Rescue organizations will have a hard time using a protocol that takes hundreds of days to be effective.

Knock on wood. Haven't had heartworm positive here, though many neighbors have. I treat with Ivermectin marketed for livestock at about twice the dose of Heartguard every month ... pretty sure this prevents maturation of filaria that may be present due to mosquito bites. I have Labradors . . . no Ivermectin intolerance.

My heart goes out to people who find a HW+ and are faced with $$$- problems. I distrust big pharma, and IMO the American Heartworm Soc. has the trappings of an outfit dedicated to selling an expensive product when there's a simpler and safer, but much slower, way of treating the problem.

There is a reason that the discoverers of Ivermectin got a Nobel prize! The drug may face problems with resistance down the line, but for the time being, IMO, it's a miracle drug for many parasitic infestation. As I read the literature, the understanding of the symbiotic relationship between the HW parasite and its doxycycline-intolerant symbiote is very important to designing a treatment protocol. Slow kill is faster and more effective if the symbiote is targeted before the HW parasiite.


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## MagicSmoker (Sep 16, 2014)

I decided to hold off on the Immiticide for another 2 weeks, both because I want a bit more time to consider my options and so Lucy will be on the doxycycline for a full 30 days before commencing adulticide treatment (whether that will be Immiticide or a double/triple dose of ivermectin every week/month/whatever [no two sources seem to agree on that]).




sandgrubber said:


> Rescue organizations will have a hard time using a protocol that takes hundreds of days to be effective.


Hmm, that's a good point which I had not considered! 



sandgrubber said:


> Slow kill is faster and more effective if the symbiote is targeted before the HW parasiite.


Yes, that is what I have concluded from my research - more specifically, that 30 days of doxycycline to kill all the Wolbachia, render the L2/L3 microfilaria non-infective, and sterilize the female adult worms is a good idea regardless of which protocol is chosen. 

That said, I am still leaning towards the fast kill protocol, both because the bewildering variation in the specifics of the slow kill protocol I mentioned above don't inspire confidence, and because my primary concern was a pulmonary embolism from dead worm fragments, and that risk, I have since learned, is mainly proportional to the # of adult worms, rather than the time it takes to kill them (as long as they don't all die at once, as would happen with the original Immiticide protocol of 2 injections 24 hours apart).


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## sandgrubber (May 21, 2014)

In your position I'd probably make the same decision. I do have some cash. Lots of my neighbors are living on social security after retiring from low wage jobs. $1000+ would be a BIG sacrifice for them, and I'd guess a well managed doxy+IVR routine could come in at < $100 for drugs plus vet time. With a sympathetic vet, this could relieve some folks from having to make a very hard decision.


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## MagicSmoker (Sep 16, 2014)

Here's an update on Lucy...

She finished the 1 month course of doxycycline about 3 weeks ago and her appetite returned to normal the next day. Also worth noting is that her monthly dose of Heartgard did not cause any problems, as it did BEFORE she took the doxycycline. So that proved to be a helpful component of the treatment (not that idiot laypeople such as us should be questioning the wisdom of Establish Treatment Protocol... ahem...).

Yesterday morning I dropped her off for the first injection of Immiticide and she stayed overnight for observation. The vet reported that she did not suffer any adverse reactions while there and she appeared perfectly fine when I picked her up this morning. When we got home she ate her food and did her business normally so everything seems fine as of now, but most of the side effects reported in the Immiticide brochure occur after 1-10 days. If any occur I'll report here, otherwise she is on activity restriction and will be getting the final 2 injections on July 26/27th.


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## sandgrubber (May 21, 2014)

Thanks for the update. Good to hear Lucy is doing well on treatment. Hope it continues to go well.


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## MagicSmoker (Sep 16, 2014)

Hopefully the last update... Lucy got the final 2 shots of Immiticide on the 26th and 27th and overall everything went okay, if not entirely without incident... The first injection 6 weeks ago went very smoothly with no pain or other side effects; in fact, if I was a less trusting/more paranoid person I might have questioned if she received any treatment at all. This time, however, she seemed to be in quite a bit of pain after receiving each injection which I am given to understand is fairly common. However, my vet thought it was sufficiently unexpected to call me up and ask for permission to charge me $21 more to give her some Tramadol. Needless to say, I was not terribly impressed by this ethically-questionable bit of nickel-and-diming, but I agreed to them giving her pain medication.

When I picked Lucy up from the vet she certainly wasn't in good spirits - either from the pain or being doped up with Tramadol - and later that night she didn't eat her food (did eat a couple of treats, though) nor did she want to drink any water. The former I didn't worry too much about but not drinking is always concerning. Still, I decided to wait to see how she was the next morning and things had definitely improved. She still wasn't too interested in food, but she did eat about half of what I put in her bowl and she drank plenty of water. She also didn't seem to be in any obvious pain so I decided to hold off on giving her more Tramadol and that proved to be okay, as she steadily improved in spirits, etc., throughout the day.

Now she is more or less back to normal, though she still needs to take it easy for about a month. All in all this wasn't nearly as bad as I feared it would be and hope my experience helps others with the same decision. Now I am going to try to get the heartworm preventative manufacturer to pay for her treatment, though I'm not holding out much hope for that...


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## sandgrubber (May 21, 2014)

Horrid parasite. Awful treatment, but a lot better than dying of heartworm.


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