Dr. Mark is a veterinarian. He works mostly with dogs and exotic animals.

Heartworm medications are available at your nearest vet's

Heartworm medications are available at your nearest vet’s office.

Senior Airman Aubrey White, Public domain, via Wikimedia Commons

Cheapest way to Treat Heartworms

Can you buy heartworm prevention for your dog for less than 10 dollars a year?
Sure you can.

Heartworm preventative is a big expense for everyone that keeps dogs. It
should be readily available to everyone, no matter what their income is, since
it is a terrible disease. It’s worse than many others because it is so easy to

Why Is Heartworm Preventative so Expensive?

The big drug companies that sell heartworm preventative make a healthy profit
off of their products and are not about to help owners find a cheaper option.
I do not have stocks in these companies, do not market their products, and do
not mind if you find an alternative. What I care about is seeing that all dogs
are healthy, and I would like to give you this alternative that I use.

What is the alternative? You can prevent heartworm disease by using the same
medication that is sold by the drug companies for a fraction of the price. If
you have a large dog, you can order the generic ivermectin from Amazon.com. (I
have large dogs, so this is the form of ivermectin that I give them to prevent
heartworm disease.) The cost of a 50cc bottle is about equal to a six-month
box of heartworm preventative (or much less, depending on where you are buying
your preventative). When the generic ivermectin arrives, it should be kept in
the refrigerator. The expiration date is about three years.

The Ivermectin Dose

Quite a few of the doses listed for generic ivermectin on the internet are
absurd and the label on the most common heartworm preventative is only 0.006
mg/kg. Since ivermectin is sold at 1%, or 10mg/cc, a 20 kg dog needs less than
0.05cc. Even when you are giving the dose to a big dog, the ivermectin dose is
so low that it needs to be drawn up with an insulin (diabetes) syringe.

The only insulin syringes I can find online with a needle are for sale only as
a full box, and you do not need to buy 100. You really only need one. There
are larger syringes for sale with needles, but you cannot use a large syringe
to dose a dog. I would recommend you try to buy a single insulin syringe with
a needle from a local pharmacy. It would be cheaper and more accurate. Since
the insulin syringe does not need to be sterile, you can reuse it. I keep mine
in the refrigerator next to my ivermectin. I do not have children at my house,
so I do not need to worry about the syringe in the refrigerator. If you need
to be concerned, please keep it out of reach of children.

Can I Use the Syringe Every Month?

There might be some concern out there about reusing the needle and drawing up
a small amount every month. The medication should be kept refrigerated to
reduce bacterial growth. Most importantly, the ivermectin should only be given

Dogs have a lot of healthy bacteria population flourishing in their gut and a
small dose on a dog biscuit is not going to affect them. If you needed to give
this medication on top of a dead and rotting squirrel each month, I would be
concerned about GI upset; a drop on a little biscuit does not worry me.

What About a Small Dog?

If you have a small dog, the ivermectin available for cattle is much too
concentrated. There are several options to make it more diluted. You can make
up a 30:1 dilution using propylene glycol. At this dilution rate, 0.1cc
contains only 333 micrograms of ivermectin, so it is easy to dose a small dog
at 0.1 cc per 10 pounds. The site recommends mixing 0.1 cc of ivermectin 1%
with 3 cc of propylene glycol.

The only problem with that is buying the propylene glycol, keeping an extra 3
cc syringe around for dilution purposes, and having another container to keep
the dilute ivermectin in.

The other option is to use the 0.08% ivermectin drench for sheep. It is the
same product I use for my large dogs. An eight-ounce bottle is enough to treat
a 100-pound dog hundreds of times. If you have smaller volumes available, or
want to divide up a bottle with your neighbor, it will not be any more
expensive than the product marketed for cattle. There is a two-year expiration
date, so even if you had to buy a bottle by yourself, it would only cost about
$15 per year.

Dogs only need about 3.5 micrograms per pound to safely prevent heartworm
disease, according to the makers of Heartgard, but due to some recent research
done at Auburn, I am including the dose for about 7 micrograms per pound.
Since one milliliter of the sheep product contains 800 micrograms, here is
what you only need to give.

Dose of sheep drench ivermectin| Weight of the Dog| Number of Micrograms

0.1 ml


up to 12 pounds


80 micrograms

0.2 ml


12-26 pounds


160 micrograms

0.3 ml


27-50 pounds


240 micrograms

0.4 ml


51-70 pounds


320 micrograms

0.5 mll


71-90 pounds


400 micrograms

0.6 ml


92-112 pounds


480 micrograms

Do I Have to be Very Careful With the Dose?

Since you are using such a small amount of this drug, you could even double
the dose and still only use a tiny amount. There is a comment in the
advertisement about this cattle ivermectin being dangerous for dogs. If it is
given as an overdose, it will be dangerous. Ivermectin is used at a much
higher dose when treating demodectic mange (0.3-0.6 mg/kg) and for a long
time, an average of 3-8 months. It is quite safe even at those levels.

Scroll to Continue

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It would be more economical to treat the larger dogs with the cattle
ivermectin, but if you have small and large dogs, the sheep product is easier
to use. You can decide which product is right for you.

When the correct ivermectin dose is drawn up, you can put it on a dog biscuit
or other dry food that your dog likes to eat. The volume of medication is very
small but be sure to put it on a treat (something stinky!) where she will not
notice the smell.

Can Ivermectin Cause Problems in Some Dogs?

Owners of Collies, Shelties, OES, Aussies, and some other mixed breed dogs
might be sensitive to ivermectin. If your vet has been reluctant to prescribe
heartgard to your dog, and you are concerned in any way, you can test for the
mutation on the MDR1 gene that causes sensitivity. Testing is available though
the Washington State University College of Veterinary Medicine.

Of course, these dogs can be given heartworm preventatives that do not utilize
ivermectin (Revolution [selamectin] and Advantage multi [moxidectin] are both
topical so treat fleas as well as preventing heartworm disease). Both of these
medications are fairly new and will need to be purchased from your

Ajej and Achilles playing on the beach.

Ajej and Achilles playing on the beach.


Is Heartgard Plus Better Than Ivermectin?

Heartgard Plus contains ivermectin as well as pyrantel pamoate, a dewormer.
This is one of the cheapest dewormers on the market, used to treat roundworms
in puppies. Roundworms may not even be an issue in adult dogs unless they are
nursing. The drug also treats hookworms, a more important parasite and one
that should be controlled.

Effective dewormers can be bought without a prescription. Even if your dog was
continuously exposed, it would still be cheaper to buy these drugs separately.

Dogs exposed every day, year-round

Dogs exposed every day, year-round

Closing Thoughts

If you have a small dog, are nervous about drawing up the ivermectin into a
syringe, if you are afraid to figure out the dose for your dog, or if you
believe the advertisements and think that the branded product is safer than
generic, then you are better off paying a little more and buying the product
sold by your veterinarian.

This method is not as easy as picking up a package and giving your dog a
chewable every month. No matter what method you use, please continue
protecting your dog however you feel is best.

This article is accurate and true to the best of the author’s knowledge. It
is not meant to substitute for diagnosis, prognosis, treatment, prescription,
or formal and individualized advice from a veterinary medical professional.
Animals exhibiting signs and symptoms of distress should be seen by a
veterinarian immediately.

Questions & Answers

Question: Do I have to make sure my dog doesn’t have Heartworm before
giving her the ivermectin? Also, is it a once a month dose?

Answer: Ivermectin is used in the “slow kill” method to treat dogs that
have heartworms. So no, you do not have to be sure your dog is heartworm
negative before starting the preventative.

Some vet techs/vet receptionists will tell you that you can kill your dog if
you give heartworm preventative without having a heartworm test first. This is
not true. In the 70s and 80s we used a medication called Filaribits, and if
the dog was not heartworm negative before prevention was given he could have
problems. This is not the case with ivermectin.

The ivermectin only needs to be given about every 45 days. The reason that
companies recommend once a month is so that people do not forget. (Always give
heartworm preventative the first of the month, etc.) If they tell people every
45 days, dogs are more likely to miss a dose, be given medication late, etc.

So yes, it is okay to give it once a month. Try the first of each month.

Question: My vet has been treating my twelve-year-old Australian female
for heartworm for two years at least. She has been given shots 3 different
times to kill the babies but nothing that effects the adult works. Is there
anything else besides the regular monthly heartworm treatment?

Answer: I am not sure if the vet is using a very low dose because of
safety concerns, the condition of your dog, etc. It is impossible for me to
say since I have not examined your dog.

If this is taking so long, the alternative is the slow kill method. You use
monthly heartworm preventative year round to kill any new babies. The adults
die off by themselves. Please reference this article:

I do not think you should give your dog any more injections to kill the

Question: I mixed the dose of sheep drench with a blob of peanut butter
and she ate it right up. My question is, you say to use a dry biscuit which
she would never eat with the medicine on it. Did I make a mistake by using a
moist media instead of a dry one for giving my dog medicine?

Answer: I just suggest using a dog biscuit since it is easy and most
people have biscuits in the house. If your dog likes peanut butter instead
that is great. Anything that masks the taste helps a lot.

Question: Do you have to dilute the sheep drench ivermectin like you do
with the cattle pour on?

Answer: The doses that I list for the sheep drench are for the undiluted
product. No, you do not need to dilute it any futher.

Question: I do not know if I can give the heartworm injectable
formulation orally. Are the oral and injectable formulations the same drug?

Answer: The active component, ivermectin, is the same. The carrier
molecule in the injectable solution is propylene glycol. This compound has
been tested by the US FDA, and is generally listed as safe. It is used as a
replacement for ethylene glycol in those “pet-safe” antifreeze solutions that
you can buy. Would it be okay to give a couple of liters of propylene glycol
orally? No, probably not. In this formulation, you are giving a very, very
tiny amount.

As far as the sheep drench, it is an oral product. If you look at the dosing
recommendations, you will see that it is a very tiny amount. If you have any
doubts about this, I suggest you continue to buy the oral product that is sold
through your vet. after all, it went through a 30-day test.

Question: I live in Georgia. I have a 130 lb dog. What dose of ivermectin
would I give him every 1st of the month? Would I put it on his food or inject

Answer: In a separate container, add 1 ml (cc) of the ivermectin and 30
ml of olive oil. Shake it up so that the ivermectin is mixed thoroughly. When
you have made up this solution, give your dog 1.1 cc of this solution on the
first of every month.

It is better to give him ivermectin directly into his mouth so that he does
not spit it out/refuse it. Sometimes they will do that since the medication
tastes bad.

Since you are in Georgia, I do want to advise you that there has been
ivermectin resistant heartworm discovered in some places in the south. Talk to
your local vet and find out if this is a problem where you live. If it is, one
of the other products may be safer. They will, of course, be a lot more

Question: What do you recommend for intestinal parasites and fleas if
changing from Trifexis to ivermectin?

Answer: It depends on what kind of parasites. The product in Heartgard,
pyrantel pamoate, does not kill all parasites but is okay for roundworms. If
you want to use that, you can purchase it VERY cheaply from Amazon. I think
the best thing to do, however, takes your dogs stool sample to his regular vet
a few times a year and have him checked for worms. It is likely that he will
not even need any kind of treatment.

Fleas are another matter. If you live in an area where fleas are a big
problem, it might be cheaper to use a medication like Triflexis that gets the
fleas and prevents heartworm. If fleas are not much of an issue, you can use
an over the counter topical (like Frontline or other inexpensive topicals sold
in pet shops) or use natural flea control methods like a flea comb, vacuuming,
and diatomaceous earth.

It depends on how big a problem fleas are, and how much you or the dog are
bothered by them. I know some clients get upset if they see one flea.

Question: I have two medium size dogs; one is 47 lbs and the other is 56
lbs. Would the dosage of ivermectin be 0.05 ml? Does this have to be injected,
or can it be digested, via giving with food?

Answer: The cattle strength ivermectin is more difficult to dose for
small and medium-sized dogs, so I would recommend you purchase the sheep
drench instead. The correct dose for your dogs would be 0.3 ml for the smaller
and 0.4 ml for the larger dog. The oral sheep dewormer is very affordable.

Both solutions, the cattle and the sheep product, can be given orally, just
like Heartgard from Merial. It should NOT be injected.

Question: We live in Georgia and have a 60 lb. vizla/hound mix and an 80
lb. Labrador. They were both taking Trifexis. This took care of heartworms,
fleas, and hookworms etc… What would be better the generic ivermectin or the
sheep drench? And can you tell me the dosage for each of them in the suggested

Answer: Since you mention you live in Georgia, I would first want to
recommend that you ask your local vet if ivermectin resistant heartworm is in
your area. If it is, neither of these products are reccomended. Trifexis costs
a lot more but as of this time no heartworm microfilaria have built up a
resistance to this drug.

If you are going to use the ivermectin in your area, the generic ivermectin
and the sheep drench contain the same drug. The sheep product is easier to use
since it is not as concentrated, so I would suggest you use that. A bottle
will last you several years, and if you share it with a neighbor you can use
the doseages that I refer to in the article.

The smaller dog will need to get 0.4 cc and the larger dog 0.5 cc. This dose
is small and should be given with a tb syringe (1cc).

If you buy a bottle of the ivermectin for cattle, (the generic product) even a
large dog like the Lab only needs 0.024 cc. This is less than 0.05 cc, which
is really the smallest dose that you can actually give.

You would need to make up a 1/30 solution to use the cattle strength
ivermectin. To do so, add 1cc of ivermectin to 30 cc of olive oil. Mix
thoroughly. At this dilution the Lab will need 0.7cc, the Vizsla 0.5 cc. This
one ml of ivermectin will last you about 2 years.

© 2012 Dr Mark


Dr Mark (author) from The Atlantic Rain Forest, Brazil on August 16,

Jan, it is really necessary in some areas. When I worked in the Mississippi
valley I saw many dogs die of this painful disease. Other parts of the US
never have a problem.

It is one of those situations where the costs are not worth it, until they
are. It is a horrible way for a dog to suffer and die.

Jan on August 16, 2020:

We’ve always had dogs never have given heart worm pills even to our outside
dogs never had any of our dogs get Herat worms …we’ve had 5 dogs at one time
….now have one indoor dog I just was wondering is it really necessary?

Dr Mark (author) from The Atlantic Rain Forest, Brazil on May 13, 2020:

Dexter, just go into Amazon and add this into the search: 1ml 1cc Syringe with
Luer Slip Tip, No Needle, Sterile (Pack of 50)

That is the box of 50, about $6, or you can probably buy 1 one cc syryinge at
a local feed store.

I Dexter on May 13, 2020:

Dr. Mark, I’m confused about what type of syringe to get for the sheep drench
ivermectin. I have a 16lb schnauzer, so I understand I need to give .2ml,
correct? I just don’t know the proper syringe to buy (U40, U100, etc.) Any
chance you could provide a link to the right kind just so I know (even if it’s
a box of 100)? Thanks so much forthis article!!! I have been using Nuheart for
6 years, but can’t get it because of the Covid19 pandemic!

Dr Mark (author) from The Atlantic Rain Forest, Brazil on August 06,

Annalyn, no, I just stopped the chart at that number because it is so unusual
to see a dog over 112 pounds. If your dog weighs that much you can go ahead
and give 0.9cc safely.

Annalyn Paz on August 06, 2019:

Is there a maximum dose currently used? My dog weighs 160 lbs and is very

Dr Mark (author) from The Atlantic Rain Forest, Brazil on January 18,

Peg, no, it is not. It is very concentrated, and you are most likely going to
overdose and kill your dogs, unless they happen to weigh as much as one of
your horses.

Buy the medication in the sheep strength. It is worth it to avoid the
potential heartache.

Peg on January 18, 2019:

Is Bimecten 1.87% (what I use for my horses) safe to substitute for the

Dr Mark (author) from The Atlantic Rain Forest, Brazil on October 19,

Samantha, currently doxycycline is recommended for secondary Wolbachia
infection. Some vets even think that this infection is responsible for most of
the side effects.

Samantha S Heinz on October 19, 2018:

I work with an animal rescue in NC. I have been mixing ivermectin heartworm
preventative for many years. Several local vets have checked my “recipe” and
found it to be accurate. I use the 1% ivermectin and dilute 2.5 ml with 40 ml
of an oil based skin and coat supplement. It tastes better if it has salmon or
cod liver oils. The dose of the mixture is 1 ml per 50# dog. We have diluted
further for small dogs as it is still hard to give such a tiny amount. This
will separate and has to be shaken well before drawing up the mixture to give.

One local vet also told me that if this mixture is given at 1 ml per 5# it
will kill roundworms, hookworms and whipworms. We do not give this amount to
herding breeds that might be ivermectin sensitive or to heartworm positive

When funds were especially low, we have used this ivermectin dose as the slow-
kill method of heartworm treatment. We gave the preventative dose every 2
weeks and all dogs tested negative when checked at 6 months. If people use the
slow-kill method, do you recommend giving doxycycline to kill the Wolbachia
parasite that lives symbiotically with them? This is the current practice of
our local vets.

Dr Mark (author) from The Atlantic Rain Forest, Brazil on June 16, 2018:

You do not need a prescription to purchase ivermectin through Amazon.

DividendRaptor on June 15, 2018:

Have you used any of those websites you have listed to purchase pet meds with
no prescriptions? Please point me in the right direction as there is a lot of
bad reviews out there.

Dr Mark (author) from The Atlantic Rain Forest, Brazil on June 15, 2018:

Cassaundra, yes, you can keep it in your fridge.

I have big dogs too and use it without diluting. The problem is though that
the 1% ivermectin has a very low dose. (For your dog, for example, would only
receive 1/30th of that 1.1 cc dose)

You can give it orally, without diluting it, but if you give too much an
overdose is more possible. (Since I give very large doses for dogs with
demodectic mange I do not worry about this.) If I were to recommend people
give a larger dose, and the dog got sick or died from the ivermectin, I would
feel responsible. Maybe not legally, but definitely morally.

If you still want to give the undiluted ivermectin, I would recommend you use
a dropper bottle. Your dog would only need one drop once a month. As you can
tell, a bottle of this ivermectin is going to last you a long time, as long as
the expiration date.

Cassaundra Green on June 15, 2018:

Thank u so much for ur reply.. I just have a couple other questions..once I
mix the 1ml (cc) of ivermectin with the 30ml (cc) of Olive oil and give my 130
lb fur babe 1.1 ml (cc) of this solution..should I keep this mixture and store
it in the fridge for the next month or toss it? Can I ever just give my fur
babe the ivermectin without the olive oil? If so what dose?

Dr Mark (author) from The Atlantic Rain Forest, Brazil on May 02, 2018:

Paige, Alabama is a grey area. Most of the heartworms that are resistant to
ivermectin have been found in the Mississippi valley and Georgia. I can
understand what you are saying about the grain allergy, but you really need to
talk to a local vet and find out if any of the dogs on Heartgard have had
problems. If not, the sheep drench is okay. If they have, the sheep drench
should not be used.

Paige on May 01, 2018:

I have a pit bull 3 years old and is 80lbs we live in Alabama do you think
sheep drench would be a good option For him? We are trying to save money any
way we can due to him having a grain allergy And having to buy expensive dog

JeanieD on October 17, 2017:

I found Sheep Drench at Tractor Supply. Sighuff, do you have Tractor supply in
your area?

Dr Mark (author) from The Atlantic Rain Forest, Brazil on October 04,

I think the sheep drench was on there but HP took it off. It is available on
Amazon, but you can also get it at a feed store. Do you have any around where
you live in Fl?

That Triflexis sounds really expensive. As far as treating worms, the only
times dogs drag their end because of worms is when they have a tapeworm
infection. You can find little white segments-similar to grains of rice-so I
cannot see it happening every month. Ask your local vet if tapeworm infections
are a big problem in your area.

Sighuff on October 04, 2017:

(Also, I don’t see where to buy the sheep drench?)

Sighuff on October 04, 2017:

Trifexis costs me $24 per month per dog (so $72 per month for all three).
Three days after they “miss” their Trifexis, they’re all scooting on the
ground, so I think they do need to be de-wormed monthly. Do you still think
Trifexis is the cheapest route for me?

Dr Mark (author) from The Atlantic Rain Forest, Brazil on October 04,

Sighuff, if you are in Florida, the triflexis may be the better buy for you,
depending on what you have to pay. I live in the tropics and use natural flea
control, treat for internal parasites only as needed.

The generic ivermectin is once a month, and for dogs even the size of yours
the meds are hard to measure, which is why I recommend the sheep drench.

Sighuff on October 04, 2017:

I’m just not completely clear on the dosage for the generic ivermectin
injection (the bottle shown, that links to Amazon for purchase). I have a 64
lb dog, a 69 lb dog, and an 84 lb dog. Also, this is still once a month,
correct? Finally, my dogs are currently on Trifexis year round (we live in
Florida). What can I use for deworming and flea prevention that will work
here? It’s a BIG issue where I am. Thanks in advance!

Dr Mark (author) from The Atlantic Rain Forest, Brazil on August 04,

Lauralee, since you are in that state (my jees are not workin on this PC! the
ivermectin in Nuheart may not be workin. the dose is okay in other states up
north. Read up on resistant heartworm infections, and talk to your local vet
to see if it has been dianosed in your area.

Keep up on the alternative flea prevention!

Lauralee on July 26, 2017:

Hello! I have a 4 year old yellow lab weighing approximately 65-70 lbs. She
has been on Nuheart (large dog) since August 2015 when we adopted her. She
tested negative in 2015 and in 2016. Based on reading another of your
articles, I am considering not getting her tested this year, but still
continuing on the Nuheart which I buy from Australia. My question is
concerning the dose of Ivermectin in Nuheart. Each once-a-month pill is 272
mcg. Will that be effective or should she receive more? In case it’s
important, we live in Georgia.

Also, we have stopped using topical flea/tick treatments this year (even
though the ticks have been horrendous due to a very mild winter). I have
started giving her brewer’s yeast tablets with garlic and also 1-2 cloves of
garlic a day, plus a couple of tablespoons of apple cider vinegar in her water

Many thanks!!

Dr Mark (author) from The Atlantic Rain Forest, Brazil on May 10, 2017:

Thanks SmartandFun, I appreciate your comments and interest. A lot of the
damage from HW may be from the Wollbachia bacteria, which is why the
doxycycline may be helpful in many of the cases. We learn all the time, and HW
is not killing as many dogs as it used to when I started out back in the 70s.

SmartAndFun from Texas on May 04, 2017:

Eduardo, I have read online that giving the antibiotic doxycycline along with
ivermectin is more effective than ivermectin alone for dogs which are
heartworm positive. If you Google it, you can find information online,
including how much doxycycline and ivermectin to give each day within a
certain treatment timeframe. Apparently doxycycline is common and inexpensive.
One person wrote that they easily got it online without a prescription, but I
believe doxycycline is a prescription-only medicine so I don’t know what to
make of that.

I am not a vet so I would love for Dr. mark to chime in with his professional
opinion. I only happened to read up on this a couple of years ago when I
feared my dog was heartworm positive (luckily, he was not) — so I don’t have
any experience with this. I just wanted to pass it along to you in case it
would help you rid your corgi of heartworms while staying within your budget.

I also wanted to send out a big thank you to Dr. Mark for sharing his
professional expertise with us random people on the internet. If you already
have an article on doxycycline/ivermectin please forgive me for not realizing
it. Thanks again; you are providing a very helpful service!

Dr Mark (author) from The Atlantic Rain Forest, Brazil on May 03, 2017:

Eduardo, for the majority of pets that are infected, this will work to kill
the youn worms, and the oldest will die out over time. It will not prevent any
further damae to the heart, and neither this nor traditional therapy will take
care of damae already done. (Sorry my letter jee is not workin, will me lots
of mistakes. try readin articles on the slow kill method to treat heartworm

Eduardo Beltran on April 24, 2017:


I have a small 16lb Penmbroke Welsh Corgi who unfortunately was tested
positive for heartworms. He doesn’t have any side effects yet, but I know
he’ll only get worse and that’s why I want to start treating him ASAP. The
cost to treat him is a little high and out of my budget at the moment. If i
treat him with this medication, will this help him get better? What would be
the dosage to give him? Any suggestions? First time every having to deal with
this even though I live in Texas, where mosquitoes are everywhere.

Dr Mark (author) from The Atlantic Rain Forest, Brazil on January 06,

jrsummersill1: There is actually a pretty wide margin of safety for the
ivermectin, so if he gave you the larger dose it may be because of resistance
in your area. It is so cheap in that form that if I were in your shoes I would
go ahead and keep following his recommendations. (In areas with no resistance
you could use half that, but as I said you should go ahead and use the dose
recommended in your area.) Thanks for the nice comment!

jrsummersill1 on January 05, 2017:

Dr. Mark,

I have read a few of your articles and find them very helpful. We currently
have 5 large dogs ranging from 50-60 lbs a piece and have been using the
cattle strength of ivermectin for years. Our vet actually gave us the dosage
and a syringe–.10 cc’s per 10 lbs of body weight. If I am reading your
article correctly, though, we may be actually giving them too much each month.
If so, what would be the correct dosage please?

Dr Mark (author) from The Atlantic Rain Forest, Brazil on January 19,

If you are sure about your dog´s weight, the treatment is 2400 mcg, or about 3
cc of the sheep drench. Some sources say every 3 days, others daily, and it
usually is given for 60 days after the last negative skin scraping, so usually
3-8 months.

If you do not have a vet to do the skin scraping, give the meds at least a
couple of months after the skin clears up.

It is a lot of work. If you can get him in to a local vet to watch the skin
during the treatment I would definitely recommend it. Best of luck to you

Roybot on January 19, 2016:

Hey Dr.Mark, nice page, great info. I was wondering, how much Ivermectin is
needed for a 175lb. dog with mange (I have the sheep drench)? Is the dose to
be given weekly or daily and for a certain amount of time, or until symptoms
totally wane? Thanks very much Dr.Mark.

Tricia and Gene from Southwest Louisiana on May 05, 2015:

Thank you for your help and quick response.

Dr Mark (author) from The Atlantic Rain Forest, Brazil on May 04, 2015:

Hi Tricia and Gene, for a dog that big give 1400 mcg, which is about 1.7 ml.
Obviously you will not need to buy an insulin syringe for your dog as a
regular syringe will work just fine.

Since that is so much ivermectin, he might not like the taste. You can mix it
with something else he likes (cream cheese, peanut butter, etc) to disguise

Tricia and Gene from Southwest Louisiana on May 04, 2015:

Can you please tell me what the dosage would be for my 200lb English Mastiff?

Thank you for all the great advice.

Dr Mark (author) from The Atlantic Rain Forest, Brazil on March 22, 2015:

The company that sells heartgard (ivermectin that you buy through your vet)
recommends it be given every 30 days, but it is actually safe to give it every
45 days. Yes, I agree there is still conflicting information on the disease
but I still think 45 days is the safest interval that we can count on at this

marjon3 on March 22, 2015:

Hello again. Does ivermectin kill larvae, or does it only kill the
microfilaria? As i mention i live in nc by the coast. Would it be safe to
treat my 3 pound dog every 75 days? There are conflicting information on how
long it takes for microfilaria to change into larvae! Can you please help me
undrestand that better? Thank you

Dr Mark (author) from The Atlantic Rain Forest, Brazil on March 17, 2015:

I can understand your feelings and if you lived further up north I would not
even recommend this. A little Maltese or Chi in the house all the time is
unlikely to be exposed, but even one worm can destroy them so it is not worth
the chance.

Thanks for your kind words. If I can help you in any way just drop me a note.

marjon3 on March 17, 2015:

Thank you so much Dr. I’m so afraid of commercial drugs. It kills me that i
have to give him poison. Unfortunately i live by the coast in nc and i have no
choice. I will try sheep drench. Will give him every 90 days from may to jan.
Thank you again for taking time helping so many people.

Dr Mark (author) from The Atlantic Rain Forest, Brazil on March 16, 2015:

A 3 pound dog actually needs about 21 mcg of ivermectin, so you can give less
for such a tiny animal, but you are talking about a very small amount of sheep
drench and not even a TB syringe is going to dose that accurately. If you give
0.05 cc that is only 40 mcg, a very small dose.

If you are nervous about giving this tiny amount for such a small dog I would
recommend you buy the commercial product sold by Merial.

marjon3 on March 16, 2015:

Hello. I have a 3 pound dog. Wouldn’t the dosage of .05 be too much for him.
The table states the dosage up to 12 pounds. By my calculation .03 will be
more than enough. Can someone help me make sure im not making a mistake? Thank

Dr Mark (author) from The Atlantic Rain Forest, Brazil on June 23, 2014:

I´m glad you gave him another dose, dugans, since that amount is so small I
was really surprised when you mentioned the tummy upset. Good to hear
everything was okay.

For your new dog, the dose is 0.3 ml. Yes, the recommendation is to keep dogs
that have tested positive on the drug year-round. The theory behind that is to
kill any of the microfilaria (the offspring) so that no new worms develop. It
is such a small dose that I think that it is worth it, especially in Florida.

The drug really does work for 45 days, and the only reason that the company
put “30 days” on the label is so that people would remember to give it (like
on the first of every month). If you are going to keep track, and not forget,
there is no reason not to use the 45 day regimen.

Thank you for letting me know how the second dose went. The hard part about
communicating here on the internet is that sometimes I never hear the follow
up on a particular case.

Good luck on your move back to Nevada. I do not know what part of the state
you are moving to, but if it is the desert make sure you have air

dugans on June 23, 2014:

Hi Again – we, with the sibe above, gave the ivermectin with his FULL dinner 2
weeks ago and he had no tummy upset this time! NOW, we are adopting a 6 yr old
sibe who was picked up by rescue as heartworm positive last year – she went
through the slow kill method last summer and is fine now – my question is
this…somewhere i recall reading that those dogs who have been diagnosed and
treated as heartworm positive must never, ever go off of the heartworm meds –
is this true? – i like the protocol of every 45 days that you suggest (the
less toxins i can put in the better—i wish i didn’t have to do this at all!)
but we do live in coastal florida, so until we move back out west to nevada,
we feel compelled to keep it up. Can you weigh in on this please? would she be
okay on the 45 day regimen?

she is 42 pounds, so would you calculate the dosage for us as a confirmation,
so that we give her the right amount of sheep dip? we are grateful, again, for
your help – thank you dr mark!

Dr Mark (author) from The Atlantic Rain Forest, Brazil on April 17, 2014:

No, with a Sibe there should not be. Who knows is he is sensitive to the
carrier, but it is such a small dose that it does not even matter. The first,
and always best treatment, for a vomiting dog is to leave them off food for 24
hours. Sometimes just resting the tummy is all they need.

dugans on April 16, 2014:

dr Mark: are there any side effects to watch out for? we are hearing a lot of
tummy rumbling – gave it to him yesterday at lunch – he didn’t eat this
morning, then ate grass and threw up this aft – still not interested in eating
and is a bit subdued – gave our 58 pound sibe .4ml of the sheep dip orally –

Dr Mark (author) from The Atlantic Rain Forest, Brazil on March 13, 2014:

7 micrograms is still a small dose, but you could probably get away with even
less. I included the Auburn numbers because it is so cheap that its worth
giving a little extra.

As far as the expiration date, I cannot be sure. I think they put that date on
there just to be safe, but cannot guarantee that. If you are only preventing
heartworm in one dog, over 18 months you will only need about 10cc (keep 20 to
be safe) so you can split a bottle with a neighbor that has several dogs. (A
bottle is about 10 times more than you need, but they do not sell it in small

dugans on March 13, 2014:

hi dr mark! just checking – if the meds have approx. 18 months till their
expiry, are they really still usable for some time after that? also, to be
safe, my 58 lb siberian should get 0.4ml of the sheep drench according to your
calculations if you still believe the studies out of Auburn are more valid
(twice the dose from the pharmaceutical formula)

thank you so much for this info!

Dr Mark (author) from The Atlantic Rain Forest, Brazil on February 24,

If your dog is very small, less than 12 pounds, she only needs 0.1 ml of the
sheep ivermectin.

Dixie on February 24, 2014:

What is the dosage for smaller dogs using the sheep ivermectin?

Dr Mark (author) from The Atlantic Rain Forest, Brazil on August 15,

Thanks so much for coming back by and leaving the comment. I get so depressed
reading all the stories on the internet from people who have dogs suffering
from heartworm, and just because they do not buy overpriced preventative from
greedy multinationals like Merial. I am so glad I have been able to help!

SmartAndFun from Texas on August 15, 2012:

Hi Dr. Mark, I just wanted to thank you for providing the dog dosage for the
sheep ivermectin. It is a real savings! I got 8 ounces of it for $30 and it
will last for at least two years. The pharmacy where my family gets our
medicine gave me (for free!) a small medicine syringe designed for infants. It
is marked by tenths of a ml, so I can easily draw up the correct amount. It’s
very easy since I don’t have to dilute the sheep-strength version, and thanks
to your dosage chart I feel confident about the amount. Once a month when it’s
ivermectin time I just squirt the medicine into each dog’s bowl of canned dog
food (which they loooove) and they gobble up the canned food immediately
without noticing the medicine. I don’t see myself ever not owning at least one
or two dogs, so over the rest of my life this is going to save me hundreds if
not thousands of dollars! Thanks!

Dr Mark (author) from The Atlantic Rain Forest, Brazil on August 05,

Hi Mary, even the bigger boxer will only need between 189-231 mcg, depending
on which source is most correct, so it is okay to give 0.05cc of ivomec. That
is only one drop, and I usually put it on top of a dog biscuit so I make sure
the dog takes it. It is impossible to get a smaller dose than this, and the
margin of safety is so good that you can treat your smaller dog with this same
dose. (If you were treating for demodectic mange with this product your big
dog would get at least 0.2cc every day for up to 8 months). Let me know if you
have any more questions I can help with.

Mary on August 03, 2012:


Thanks for your response. I have the cattle strength and the syringes (we were
able to buy them in a sealed pack of 10 off ebay). Can you confirm the correct
dosage for my boxers, they are 46 lbs. and 66 lbs. Thank you for your help.


Dr Mark (author) from The Atlantic Rain Forest, Brazil on July 26, 2012:

The “liability concerns” is doublespeak for “don’t take away my business”. The
paste for horses is really strong (1.87%) but the sheep product looks safe
even for smaller dogs. The amazing thing is that three years worth of the
sheep product sold from a feed store costs less than 6 months sold through

I just read your comment about the metric system. All drugs are already in
metric measurements anyway, except a few old formulations like phenobarbital,
that is still called grains. It would definitely help prevent accidents like
the one you spoke of in your hub though.

Bob Bamberg on July 26, 2012:

Great hub, DrMark, and great exchange of ideas, folks. I owned a feed and
grain store and had customers who used the Ivermectin paste for their dogs,
but they were haphazard about it, putting a dab on their fingertip and letting
the dog lick it off. The syringe is calibrated for a thousand pound animal
and, if I remember right, the graduations start at hundreds of pounds. But it
sure is cheap…$7.99 a syringe and it would expire before you were able to
use it up. I asked a couple of vets if they’d work up a conversion so that
these people wouldn’t OD their dogs, but they begged off, siting liability

Dr Mark (author) from The Atlantic Rain Forest, Brazil on July 24, 2012:

Yes Mary I use this on my dog since mosquitoes are a big problem here and
heartworm is also a problem. I use the cattle strength since she is pretty big
but for a smaller dog you should buy the product labelled for sheep. It only
needs to be given once a month so I always do it on the 1st so I do not

Mary on July 24, 2012:

Hi DrMark

Thanks for the useful info. Some friends told me about this and I wanted to
double check the info.

Do you happen to use this for your dogs?

Also, is the dosing above per month?


Dr Mark (author) from The Atlantic Rain Forest, Brazil on June 27, 2012:

It seems like good insight. I think they try to scare people into believing
they are more prevalent than they really are.

DoItForHer on June 27, 2012:

My vet said Billings is seeing more of it and more dogs are treated for it
there, but he isn’t too worried about it here. A trainer here treats her dogs
for it as she feels it is enough of a concern.

Not a definitive, researched opinion, but rather some insight from some people
residing here.

Dr Mark (author) from The Atlantic Rain Forest, Brazil on June 27, 2012:

Dont they already claim it is there? I have seen maps of the US showing that
state as a low risk area, with a low level of heartworm disease.

DoItForHer on June 27, 2012:

I don’t worry about heartworm as I live far enough north to not have the
Mosquitoes that transmit it; however, it was documented 240 miles south of me
a few years ago.

It’s a matter of time before the temperature gets warm enough to allow
heartworm to establish itself this far north. (Montana)

FutureDrKate on June 23, 2012:

haha true!

Dr Mark (author) from The Atlantic Rain Forest, Brazil on June 23, 2012:

For a big lab it will be worth it, and I am sure you have access to the
syringes. It should be a good deal for you.

FutureDrKate on June 23, 2012:

That’s so interesting! Thanks!

Dr Mark (author) from The Atlantic Rain Forest, Brazil on June 21, 2012:

Thanks Brett I will go over there now. A state law? Not anywhere in the US
that I am aware of. (I do not kow how a legislator would even justify such a
stupid law.) I know there are laws about rabies vaccinations and liscences.

Brett Winn from US on June 21, 2012:

My vet said the HW test was a state law. Not sure whether that was true or not
… I am fortunate to have a vet who doesn’t micro manage … if I don’t want
a shot, he’s cool. He understands that I don’t want to over vaccinate and that
I give my own vaccinations. And yet he’s still there for me when my dog has
genuine health problems. I am blessed.

Dr. Mark, would love to know what you think of my hub
https://pethelpful.com/dogs/The-Truth-About-Dog-Va… as the hub has been out
there a couple of years now and is in danger of being dated … but only if
you have the time and are interested …..

Dr Mark (author) from The Atlantic Rain Forest, Brazil on June 21, 2012:

That is really wrong. Normal, but wrong.

Cat R from North Carolina, U.S. on June 21, 2012:

My former vet made HW tests mandatory. If your dog hasn’t been tested within a
year, you have to have it. Others make a capstar pill mandatory and charge $7
for a $3 or less pill.

Dr Mark (author) from The Atlantic Rain Forest, Brazil on June 21, 2012:

Thanks Cat. Veterinarians make their profit on vaccines instead of charging
for their exams and professional services. It is really a dumb move, and made
worse by corporate practices like Banfield that give away the exam for free
and expect to make all of their profit off of the vaccines (which they give
way too often anyway). It is the same with the heartworm preventative;
veterinarians expect to stay profitable selling something that costs many
times more than it should, and there are so many better alternatives out
there. I am glad this article helped and hope that more people can use this

Cat R from North Carolina, U.S. on June 21, 2012:

Most of my friends have been using ivermectin for a long time and I know of
quite a few dogs that became heartworm free after a certain time. I personally
prefer the tube (actually for horses), but have heard a lot of conflicting
info about the dose.

I know that my dogs tested negative after being on ivermectin for years and I
love the effect and the much cheaper price. It is sad that a lot of vets
charge so much for things that can be bought much cheaper. One of my former
vets charged $40+ for shots, but the 5-Way can be bought from Dr. Foster & Dr.
Smith online for less than $3 if you buy a box of 25 (which you can share with
friends if you only have one dog). The bordetella is about the same or
slightly more. A local rescue does $5 rabies clinics with the vaccination
bought online and still makes a huge profit.

I appreciate the info on the does and will be happy to use them. Great
article. Info like this can help people affort good care for their pets.

Dr Mark (author) from The Atlantic Rain Forest, Brazil on June 20, 2012:

This would be a big money save with those big Danes! A bottle will still last
you for years. I do not think the equine paste is great in dogs since it is
more concentrated but with your dogs it may be okay. If you need any help
getting the doses right please let me know and I will be glad to help.

Holle Abee from Georgia on June 20, 2012:

Wonderful info! I’ve used Ivermectin on horses, and I’ve always wondered if it
would work on heartworms in canines. Great to know! Voted up, etc.

Dr Mark (author) from The Atlantic Rain Forest, Brazil on June 18, 2012:

Thanks Brett, I think the MDR-1 testing is worth it too. According to the
Merial people this ivermectin dose is so low that it would not cause problems
even in sensitive dogs, but I think it is better to test if there is any

Brett Winn from US on June 17, 2012:

I have done this for years, and saved a mint, I am sure. I have Australian
Shepherds and Border Collies, but they have all been MDR-1 tested. The testing
is worth the expense for the peace of mind, especially since Interceptor seems
to no longer be available.

Dr Mark (author) from The Atlantic Rain Forest, Brazil on June 15, 2012:

Since the paste is 1.87% ivermectin, the liquid 1%, a 20kg dog would need
about 0.02 cc. This dose is very low, and the paste sold does not allow you to
dose that low. It is much easier to overdose with paste.

Dr Mark (author) from The Atlantic Rain Forest, Brazil on June 15, 2012:

´Thanks somethgblue I just highlighted a link, but need more backlinks to
other dog sites. Nabiru thanks you for your help!

Theophanes Avery from New England on June 15, 2012:

Yes I know. I had a pit bull come to me with mange that required 9 months of
daily Ivermectin to get rid of it. I realize it is the same drug, obviously. I
do not change my opinion. Its just a lot easier to overdose with liquid,
that’s all.

Dr Mark (author) from The Atlantic Rain Forest, Brazil on June 15, 2012:

All drugs can be dangerous if overdosed, even aspirin

Dr Mark (author) from The Atlantic Rain Forest, Brazil on June 15, 2012:

This should be given orally, no deaths can be caused without an overdose

Dr Mark (author) from The Atlantic Rain Forest, Brazil on June 15, 2012:

The injection ivermectin and paste are same drug

Dr Mark (author) from The Atlantic Rain Forest, Brazil on June 15, 2012:

sorry for choppy comments having salty computer problems

Dr Mark (author) from The Atlantic Rain Forest, Brazil on June 15, 2012:

Theophanes I explained in the article that the drug is to be given orally; it
is also given orally in demodectic mange

Theophanes Avery from New England on June 15, 2012:

Injectable Ivermectin is great for mange but I would not give it for heart
worm. The risk of injecting too much is too great. It only works for larger
dogs. Personally to keep heart worm at bay for my own dog and cats I use
Ivermectin paste. I buy it at the feed store where it is sold for horses. A
pony size dose costs between 7-12 dollars and it lasts for as long as its
still good. You can also buy pyrantel in the same way if roundworms are a
concern. I believe in the safety of the Ivermectin paste because I started
using it with my fancy rats (who had mites) years ago and my twelve precocious
girls sucked the whole tube into their cage when I wasn’t looking and consumed
enough for a 2,000 pound horse. None of them died. I have however heard of
deaths associated with injectable Ivermectin which is why I only suggest it in
cases of demodectic mange in larger dogs and even then only to very capable

somethgblue from Shelbyville, Tennessee on June 14, 2012:

You once told me some stats about your hubs that I find a little surprising.
You are a talented writer with a passion for a certain subject, the dog
whisperer of Hub Pages.

However the tedious and let’s face it not so exciting part of writing in this
community is using ALL of the tools at your disposal to promote your hubs.

As I learned fairly quickly passion and talent alone won’t get the word out,
so I would like to make some suggestions. If this comment is out of place
don”t hesitate to delete it.

Use some keywords in the content of your Hubs to promote some of your other
hubs that are pertinent to the subject. In edit mode highlight the phrase with
your mouse click the link button, up will pop three choices, your hubs, amazon
and other hubs. Click on one of Your Hubs and it automatically links that
phrase to your hub.

Shamelessly back link your hubs on other sites, people love their dogs and
your advice is obviously filled with love, share it!

Post every one of your Hubs on at least four social networks, FB, Pin It,
Digg, StumbleUpon, etc., use the share button at the bottom of the page . . .
. Add an RSS feed to every Hub you have published.

I don’t have a dog but have in the past and unlike most readers I read every
hub I comment on start to finish however many people don’t so grab their
attention, with quotes from famous people, startling facts, and more pictures
of the Star.

Good informative article, thanks for sharing!