Heartworm Preventatives for Shelter Dogs [discussion moved from other thread]

[LolaMarigolda]

Actually, it would probably be MUCH cheaper to use Ivomec 1% injectable for cattle and swine. Given orally, it will provide protection against hw and some of the other common worms that dogs can get; it does not work against hooks or tapes. A 50ml/cc bottle will treat 5K pounds of canine. Besides the cost benefit, you can actually administer the doses for the exact weight of the dog, which is better for those dogs that are under 10# or at the lower end of the weight range for some of the other meds on the market.

The only down side is that you must use caution on collie or shepherd breeds since some carry the MDR1 mutation which makes them not tolerate certain medications well (there is a long list of meds that the gene affects). It has been shown that when given at the proper dose, Ivomec generally (like 99% of the time) will not cause a reaction in a dog with the mutation, but that higher doses (5X+ the recommended) will.

It is dosed at 1cc per 100 pounds of body weight. If you use an insulin syringe, you can dose for as low as 2.5 pounds.

I've used it for years on both my APBTs and hounds; we've never had a problem and never had a dog test positive. Keep in mind that our dogs receive it year round as Florida is never mosquito free; I also know kennels in Louisiana and Mississippi that use it (where it seems some of the hws are becoming immune to some preventatives). Plus, it can be given to a hw positive dog without ill effect and over time will sterilize any adult worms and shorten their life span. I've known several vets that have treated hw positive dogs (light positive) with either 2X doses or regular dose but given every 2 weeks and the dogs tested infection free 6-12 months later. I also know of 50 different kennels (various breeds) that use it.

I have a nearly full bottle (45cc or so) that is good through 11/2012. I don't feel like going through the hassle of taking it home, so if you guys want it, let me know. I'll get out what I need for Scooter (2-3 doses) and you can have it.

ETA: Quick math says you'd need roughly 1.25 bottles a month based on 20 large dogs at 100 pounds and the small dogs at 50 pounds. Odds are that when it comes down to actual weight, you will only need a bottle a month. The bottles are generally @ $35US so with shipping figure $75. That's half of what you are paying now.

[Brown]

That sounds like an excellent idea. I will probably be coming back to Korea late June, so could bring more bottles with me (assuming it's not an illegal substance!) to keep the supply line going. I think it would be good to have them on preventatives through November really, if not year-round. I don't know the Heart Protect product, but at that price, I doubt it covers any parasites other than heartworm, in which case no difference between ivomec and the oral prophylaxis. Also, is feline heartworm an issue in Korea? As far as I know it isn't, but I don't think cats get routinely tested for it there, so maybe it's an undetected problem.


The only down side is that you must use caution on collie or shepherd breeds since some carry the MDR1 mutation which makes them not tolerate certain medications well (there is a long list of meds that the gene affects). It has been shown that when given at the proper dose, Ivomec generally (like 99% of the time) will not cause a reaction in a dog with the mutation, but that higher doses (5X+ the recommended) will.
I think it takes even more than that to cause toxicity for dogs with the MDR1 gene (and even it's mostly dogs homozygous for the mutation that are affected, ie both parents having been carriers of the mutation). The mange doses (which are definitely toxic for MDR1 dogs) are about 50x higher than the heartworm preventative dose. Is there a difference in sensitivity though between ivermectin as an oral drug and injectable ivomec? Either way, most of the dogs are mixes (and not collies or shepherds), so unlikely to be an issue fortunately.


Quick math says you'd need roughly 1.25 bottles a month based on 20 large dogs at 100 pounds and the small dogs at 50 pounds. Odds are that when it comes down to actual weight, you will only need a bottle a month. The bottles are generally @ $35US so with shipping figure $75. That's half of what you are paying now.
Most of the dogs at Asan are much smaller - small ones between 5-15lbs, and larger ones 40-60lbs, plus some in-betweeners. Very few really big dogs, so one bottle would go a long way.

[Sofia]

LolaMarigolda:

Thank you for your idea. We will consider using Ivomec for Asan shelter dogs but probably for 2012 season. I expain why:
1) it will be very-very hard to to check an actual weight for each of 103 dogs: it will take a lot of time, it will be very diffucult to catch every dog (now they live in the open pens), some of the dogs are agressive, some of them are very shy, if some of the dogs will show negative reaction to Ivomec there is no any vet around to help and etc.
When given a piece of canned food with a tablet inside, they come to us themselves.

2) we will start h/w prevention on coming Saturday and it's no time to order and wait for delivery.


Brown:

If someone could organize testing all Asan shelter cats for h/w and providing them with prevent. meds it would really be great.

[LolaMarigolda]

That sounds like an excellent idea. I will probably be coming back to Korea late June, so could bring more bottles with me (assuming it's not an illegal substance!) to keep the supply line going. I think it would be good to have them on preventatives through November really, if not year-round. I don't know the Heart Protect product, but at that price, I doubt it covers any parasites other than heartworm, in which case no difference between ivomec and the oral prophylaxis. Also, is feline heartworm an issue in Korea? As far as I know it isn't, but I don't think cats get routinely tested for it there, so maybe it's an undetected problem.

As far as I know it isn't on a banned list. It's a really common drug for the cattle/swine industry as well as small farmers. I tried looking up the Heart Protect product and couldn't find anything. Most people don't realize that Ivomec does cover some worms; the only thing the Pyrantal Pamoate (that is in products like heart guard plus) covers that Ivomec doesn't is hooks.

I would imagine that since canine heartworm is here then feline is here as well. The problem with treating cats (especially kittens) is that they are soo much more sensitive to what seems like everything. It appears that Revolution (a topical) is one of the current drugs of choice for feline hw prevention. Don't know how well that will work for the shelter cats; if they don't have outdoor access, then it won't be a problem.


I think it takes even more than that to cause toxicity for dogs with the MDR1 gene (and even it's mostly dogs homozygous for the mutation that are affected, ie both parents having been carriers of the mutation). The mange doses (which are definitely toxic for MDR1 dogs) are about 50x higher than the heartworm preventative dose. Is there a difference in sensitivity though between ivermectin as an oral drug and injectable ivomec? Either way, most of the dogs are mixes (and not collies or shepherds), so unlikely to be an issue fortunately.

Yes, The mutation only affects those that actually have the double recessive gene. I've heard that in most cases it takes more than 5X, but in the case of at least one homozygous merle (AKA a "lethal white") it took less. I realize those dogs aren't generally in the best of health to begin with, but it was still a bit of a shock to hear how little it took.

There is some differences in how quickly the drug starts to get into the system. Otherwise, the side effects are the same.

Most of the dogs at Asan are much smaller - small ones between 5-15lbs, and larger ones 40-60lbs, plus some in-betweeners. Very few really big dogs, so one bottle would go a long way.

I was just doing quick and dirty math. :D I do the same thing at home when we get ready to order. Everyone gets rounded up to the next ten pound increment. That means I always have at least enough extra in case we end up with an additional dog. ;)


1) it will be very-very hard to to check an actual weight for each of 103 dogs: it will take a lot of time, it will be very diffucult to catch every dog (now they live in the open pens), some of the dogs are agressive, some of them are very shy, if some of the dogs will show negative reaction to Ivomec there is no any vet around to help and etc.
When given a piece of canned food with a tablet inside, they come to us themselves.


I understand your concerns. I just threw it out there since it is 1/2 the price of what you are currently doing and since you are reliant on volunteers to pay for it. I can also understand the concern over "what happens if one does have a negative reaction". The good news is that the chances of that happening is the same as one having the reaction based on what you are giving them now. You can mix the liquid into canned food or a piece of bread.

[Brown]

I didn't realise Ivomec could be mixed with food, in which case it sounds like that would be the route to go. If I can bring bottles over, we would save on shipping and the cost would end up being drastically lower. I suspect around half a bottle would probably cover all the dogs for a month - that's about US$20.

Sofia, I don't think we would have to weigh all the animals - an approximate weight would be fine (the pills are also very approximate and the same one is usually intended for dogs within a wide weight range). The dosage of ivermectin used to treat mange is 50-100x higher than the heartworm preventative and is safe for most dogs, so I think even if we were 3x off guessing the weight (which I doubt) we wouldn't have to worry about any side-effects. Of course, it is more time and effort to measure out doses with a syringe than to give a pill, but it would save so much money that could be used for other expenses.

As for the cats, I tend to agree that if canine heartworm is there, feline is too since they are infected the same way dogs are and the cats live outside there too, so are constantly exposed. They are a bit more resistant than dogs are, and less likely to develop the disease if they are bitten by a heartworm-carrying mosquito, but they also die much more quickly and there is no treatment (they can't be given immiticide). It would be way too expensive to test all the cats at Asan, but they could be given preventatives anyway. Ivermectin is also approved for heartworm prevention in cats - the dose required is about 2-3x higher than it is for dogs as I remember.

[LolaMarigolda]

BROWN, you might want to look at the larger bottles. Jeffers has the following:
50ml/cc bottles for $34.95
200ml/cc bottles for $103.00
500ml/cc bottles for $134.00
1,000ml/cc bottles for $270.00

I do suggest using insulin syringes for drawing up the doses because they allow you to get the exact dose vs a 3cc syringe which only allows you to go to the nearest .10

I'd also suggest buying a pack of larger gauge stainless steel syringe needles and use that to leave with the bottle. I brought a 3pk with me when I came over as part of my canine first aid/medical kit.

Also, question for Sophia... where are you ordering this stuff from? Asking because someone on another forum just posted about a compounding pharmacy that is selling a preventative mix that is questionable. I don't know what they are calling it; I'll have to go back and look up the pharmacy. Wondering if it may be the same place you are using since I couldn't find any info on the product.

[Karen]

Sofia, I don't think we would have to weigh all the animals - an approximate weight would be fine (the pills are also very approximate and the same one is usually intended for dogs within a wide weight range). The dosage of ivermectin used to treat mange is 50-100x higher than the heartworm preventative and is safe for most dogs, so I think even if we were 3x off guessing the weight (which I doubt) we wouldn't have to worry about any side-effects. .

Sorry, but I have to ask: Brown, have you studied veterinary medicine? I do hope all this advice is being given with the assumption that an actual vet or vet technician will be the one to finally determine dosage and help administer the medicine? I don't think it's safe or wise to advise people to guess at weight and possibly overdose animals whose medical history and current health status is most likely not known, at least not in any detail.

[Brown]

No, I am not a vet, but I have researched a lot of vet medicine, both for my own purposes and as an editor. All this information is available on the drug manufacturers' websites, and in standard veterinary manuals.
If you look at any dosing guidelines for heartworm pills, you'll see they are also for broad weight ranges classed as small, medium and large. The minimum dose of ivermectin required for heartworm prevention is 6 micrograms per kg of body-weight. A tablet for dogs 0-11kg contains around 70mcg of ivermectin. For the 11kg dog, that is at the minimum level, but for the 3kg dog it is 23mcg/kg, the 2kg dog 35mcg.
With Ivomec, the dose is 1cc/50kg of dog. Hence, a pill for a 22-45kg dog (which contains around 270mcg ivermectin - ie 6mcg/kg for the 45kg dog) is essentially the equivalent of giving 0.9cc of Ivomec. The dogs at the top end of the weight range would be getting closer to the minimum preventative level, those at the bottom would be getting a much higher dose. It is still safe.

My point is that there is no difference between approximating the dose given to dogs of unknown weight or health status whether you are using ivermectin tablets or ivomec liquid - in this case, the dogs are not going to be weighed either way. Dosing them with pills also means guesswork. Dogs who are estimated to be borderline per the pills' designated weight range will have to be dosed up to ensure they are getting at least the minimum dose to prevent heartworm, and may end up getting more than double what they really need. I think the possible danger/concern with Ivomec would be ensuring doses were properly measured out with a syringe - wouldn't want to get decimal points confused and give 1cc instead of 0.1!

Even so, doses used to treat mange (and some other conditions) are given at 300-600 mcg/kg, ie 50-100x the heartworm preventative levels. Obviously that wouldn't be a safe level for long-term use, but the point is that it would be almost impossible to overdose the dogs. Only dogs homozygous for the MDR1 mutation (which is rare) are definitely susceptible to overdose (usually around 10-20x the heartworm preventative level and I just don't see us overestimating a 5kg dog to be 50-100kg).

Nevertheless, for reasons of convenience of administering the drug, Sofia prefers pills and since she is the one on-site and taking charge of this endeavour , we should respect her preference. I have, therefore, made inquiries about obtaining pills at lower cost than what she is having to pay in Korea, and we can indeed import generic ivermectin tablets in large quantities more cheaply, which would enable both dogs and cats to be covered for about the same price she is currently having to pay for dogs only.