So a while back i tried searching for info on ivomec, and everyone had a different answer, and everyone had been using it for years with no ill effects.
Now I don't want to hurt anyones feelings, and if you have been doing it that way for years then by all means keep on doing it. But i thought Id post this info i found so if nothing else, you guys could check it out and maybe save a little ivomec.
First, DO NOT USE IVOMEC PLUS for heartworm control on your dogs. It has other chemicals in it that could harm your dog's health. Use ONLY the straight ivermectin liquid solutions.
You should have the dog tested for heartworms first because once you start treating, the test won't work anymore. Ivermectin will not kill adult heartworms, although there is some evidence that it makes them sterile (can't breed any more so your dog is not a pool for infection) and that it may shorten their lives, usually about 2 years if untreated. So if your dog has heartworms and you start treating him without testing first, you won’t be able to tell later if he needs treatment for adult heartworms. It won’t show up on the test anymore.
That said I'm going to give you the straight skinny on proper dosage for heartworm using ivermectin. This is typically a topic that just pisses the he** out of people who have been doing it wrong for years on end because they are so positive they've been doing it right. Well, if you've been dosing your dogs in higher amounts than what is listed below, you've been doing it wrong. Whether or not that has had any sort of negative effect on your animal may well be arguable, since tolerance for ivermectin is generally quite high amongst those animals that tolerate it well. Try to look at it as you are wasting money, rather than an accusation that you're risking your dogs' health. I will note, however, that the "safe" dosage for dogs (other than collies) is considered to be no more than 200 times the recommended dosage. Some of the dosing schemes mentioned here seem to go considerably higher than that.
Here are some conversion factors to remember:
1 cc = 1 ml
100 mcg = 0.1 mg (100 micrograms = one-tenth of a milligram)
10 mcg = 0.01 mg (10 micrograms = one-hundredth of a milligram)
1% ivermectin straight out of the bottle has 10 mg of ivermectin per ml. As someone pointed out, a 50 ml bottle of this runs around $27 at Jeffers Vet Supply. This needs to be cut drastically to get it down to an acceptable dosage for dogs.
0.27% ivermectin would have 2.7 mg (or 2700 mcg) of ivermectin per ml. This is swine wormer, and I suspect the reason it isn't used by breeders is that it actually costs more than the 1%. However, most of us couldn't use up an entire bottle of Ivomec 1% cattle wormer in the 2 year period before it expires, so it may very well be a false economy to stick with the cattle wormer if you're not going to be able to use it all up anyway. I just checked, and this is $45 for 200 ml at Jeffers Vet Supply. You’d still need to cut this, but not nearly as much as it is already about ¼ strength compared to the 1% ivermectin solutions. If it were available in a 50 ml size, that would be most excellent.
To the person giving 1/10 cc of the 0.27% Ivomec to a 24 pound dog – the dose for your dog would normally be about 0.025 of a cc of this solution, so you’re probably giving your dog about 4 times more than necessary, but not a harmful dose.
USING IVERMECTIN TO PROTECT AGAINST HEARTWORM IN DOGS
The correct dosage for dogs is 0.0015 mg to 0.003 mg per pound of body weight. That's 1.5 mcg to 3 mcg per pound of body weight.
The formula someone gave that says to add .3 cc of 1% ivermectin to 1 oz of propylene glycol, and then dose at 10 mcg per pound of body weight, is for FERRETS. NOT dogs. That dose is about 3 to 7 times too high for dogs. Not likely to be actually dangerous, but it's not the correct dosage.
If you are using the 1% ivermectin straight out of the bottle and giving your dog 1/10th of a cc (0.1 cc = 0.1 ml) per pound of body weight, you are dosing your dog at the rate of 1 mg per pound of body weight. That is FAR FAR over the recommended dose of no more than 0.003 mg per pound of body weight. Even if you're doing it at 1/10 cc per TEN lbs it's still way too much. I don’t THINK anyone is doing this with the 1% ivermectin, but some of the posts were a little unclear on this. Doing it THIS way – straight, uncut – with the 1% ivermectin would be far riskier than anything I personally would want to be involved with.
If you are cutting it at the rate of 1:9 with propylene glycol, you end up with 1 mg of ivermectin per ml (it is now a 0.1 % solution).
If you then give 1/10th of a cc per 10 lbs, which I think is what people were recommending, you are still dosing at 0.01 mg per pound of body weight, or 10 mcg per pound. 1/10 cc has 1/10 mg of ivermectin in it. So a 20 lb dog would get 2/10 cc, with 2/10 mg of ivermectin in it, which is 200 mcg of ivermectin when the suggested dose for this size dog is between 23 mcg and 60 mcg. This is essentially the same as the ferret dosage, roughly between 3.5 to 10 times higher than it needs to be. Probably not dangerous, but why waste the stuff? If you’re cutting it anyway, why not just cut it down to something more precisely manageable?
Here’s what I do:
½ ml of 1% Ivomec injectable cattle wormer added to 49.5 ml of propylene glycol. There was 5 mg of ivermectin in the ½ ml of 1% ivomec, now suspended in 50 ml of propylene glycol, for a concentration of 5 mg/ 50ml. This is 0.1 mg per ml, or 100 mcg per ml.
For those slightly less obsessed with precision than I, you could make this ½ ml of the 1% Ivomec added to 10 tsp of propylene glycol (3 T plus 1 tsp). Measure this using an accurate 1/4 c measure and take out 2 tsp. It works out roughly the same. If you try to do it with a tsp or T at a time, you keep adding errors with every spoonful - use the 1/4c measure and take out 2 tsp, it'll be closer. Plus it's easier.
Multiply the weight of your dog by 2. This gives you, in MICROGRAMS, how much medication to give your dog. If it’s a little less or a little more you are still within the safe zone of 1.15 to 3 mcg per pound of body weight. You can actually use any number between 1.15 and 3, I just picked 2 because it’s easy to do in your head. Heartguard uses 2.72 as their upper limit; notice that smaller dogs are getting more, sometimes significantly more, than 2.72 mcg per pound in the weight ranges that Heartguard uses. So yes there is room for slop.
Then divide that by 100 to determine how many cc’s of the above mixture to squirt into the lil’ pup’s mouth.
SO if your dog weighs 24 lbs:
24 x 2 = 48; divide by 100 = 0.48 cc
We can’t measure in hundredths of a cc, so just round to the nearest whole 1/10th of a cc. In this case, a 24 lb dog should get ½ cc of the above mixture. (rounding 0.48 up to 0.5, or ½ cc).
SO, weight of the dog in pounds x 2 / 100 = # of cc’s of this mixture to give the puppy to protect it from heartworm.
A 100 lb dog using this solution would get 2 cc of solution. (100 x 2 / 100 = 2). Anything between 1.2 cc to 3 cc would be safe for a dog this size (it’s weight x the amount in mcg per pound, so where there is a 2, any number from 1.15 to 3 – the dosage range for heartworm control – could have been used).
Make sense?
Using the 1:9 ration, the amount of ivermectin per cc is (from above) 1 mg, or 1000 mcg. So the calculation for the 1:9 ration (1 cc of 1% ivermectin added to 9 cc of propylene glycol) would be:
For 1:9 solution ONLY: weight in lbs x 3 / 1000 = cc’s to give, or, for example:
100 lb dog => RANGE of appropriate dosage would be
100 x 1.15 / 1000 = 0.115 cc MINIMUM to 100 x 3 / 1000 = 0.3 cc MAX
50 lb dog => RANGE of appropriate dosage would be
50 x 1.15 / 1000 = 0.057 cc MINIMUM to 50 x 3 / 1000 = 0.15 cc MAX
20 lb dog => RANGE of appropriate dosage would be
20 x 1.15 / 1000 = 0.023 cc MINIMUM to 20 x 3 / 1000 = 0.06 cc MAX
We can’t give less than 1/10 of a cc, so you can see how much harder it gets to dose your dog properly the smaller they get. If you have BIG dogs, it doesn’t matter much, you can get something that falls within the recommended treatment range; but if you have SMALL dogs, you end up routinely overdosing them. That’s why I favor the lower concentration solution. I’ve never had a dog over 40 lbs, and most of them were 25 lbs or less.
Again, as long as you cut it at least 1:9 and use the formula above (more accurate than 1/10 cc per 10 lbs), you’re probably (PROBABLY) not going to do any lasting damage to your (non-collie) dog, but if you’re cutting it anyway, and you have smaller dogs, why not cut it to something a bit more manageable?
Of course, you can skip all this mixing and stuff and go right to the .27% ivomec for swine. Then the calculations would be as follows:
Weight of your dog x 3 / 2700 = # of cc’s of 0.27% Ivomec.
In this case a 24 lb dog would get : 24x3=72, 72/2700 = 0.0267 cc. Since it’s awfully hard to get less than 1/10 cc, you’d probably go ahead and give the dog 1/10 cc. This is still "overdosing", but it’s about the same as what folks are doing with the 1:9 solution or the Ferret Mix. It’s no worse, not dangerously high for non-susceptible dogs, and skips all the mucking about with having to cut the solution (and find a source for propylene glycol).
So if you wanted to skip any mixing at all, you could give 0.27% (NOT 1%) ivomec as follows:
20 lbs – 100 lbs 1/10 cc (delivers 270 mcg of ivermectin)
100 lbs – 200 lbs 2/10 cc (delivers 540 mcg of ivermectin)
I can’t imagine a dog bigger than 200 lbs, but if there are any out there, you could give them 3/10 of a cc of the straight 0.27% Ivomec. That’d be a scary big dog indeed.
I wouldn’t do this with puppies – they’re more sensitive to overdose. In fact you should not be giving ivermectin in any form whatsoever to puppies under 6 weeks of age – it can cross the blood-brain barrier just like it does in collies until they’re older. 8 weeks would probably be safer. If you’re going to dose really small dogs (under 20 lbs) and puppies, cut the stuff and stick to the recommended dosages.
Here’s a reference for dosing information that includes gastrointestinal worming and skin parasites:
http://www.petplace.com/drug-library/ivermectin-ivomec-heartgard/page1.aspx# Here’s a treatment schedule for demodectic mange that includes the use of ivermectin:
http://www.petplace.com/dogs/demodicosis-red-mange-in-dogs/page4.aspx WHERE TO GET PROPYLENE GLYCOL: Beg a cup or so off of a large animal vet, or if you know someone who raises cattle, they probably have some. I've never been able to find it to buy in anything less than a gallon size. We're talking TEASPOONS here, for most of us who aren't breeders anyway. DO NOT SUBSTITUTE ETHYLENE GLYCOL, IT IS POISONOUS AND WILL KILL KILL KILL YOUR DOG!
Do not attempt to mix with water as Ivermectin is NOT water soluble. It won't distribute evenly in water, stick with the propylene glycol.
A final note: Using my formula you end up with 49.5 ml of 1% ivomec left in the bottle, and 50 ml of heartworm preventative. My dog weighs 23 pounds; her dose should be between 0.3 cc and .5 cc. Assuming .5 cc, there are 100 doses in that 50 ml of solution. The solution should only be kept for 2 years, so basically I have to throw the rest of it out. Nevertheless, at under $28 for a bottle of 1% Ivomec, it's way WAY cheaper than buying the stuff at the vet - 2 years worth of heartworm pills from my vet for my dog cost something over $250. (It's like $12 a month). When I had 4 dogs, there was just no comparison - four dogs were running me over $50 a month.
In short, it might be nice to go in with a group of friends to buy and make up the stuff. Otherwise most of it will go to waste. Better yet, if you know someone who raises cattle, I'm sure they'd be willing to spot you a half ml or so.
Hope that all helps.
JD
