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Ivermectin Poisoning from Parasite Prevention Drugs in Dogs

By isak, December 28, 2009

This toxic reaction occurs especially in dogs that are genetically hypersensitive to ivermectin, an anti-parasite medication most commonly used for heartworm prevention, or to treat ear and hair mites, which can lead to mange. Ivermectin prevents or kills parasites by causing neurological damage to the parasite, resulting in paralysis and death for the parasite. But dogs genetically sensitive to the medication have an anomaly that allows the ivermectin to pass the dog’s blood-brain barrier and into its central nervous system, which can be lethal for the animal.
[slider title=”About Ivermectin “]Overview

  • Parasitic diseases are common in animals. Parasites can affect the skin, ears, stomach and intestines, and the internal organs including the heart, lungs and liver. Several drugs have been developed to kill or prevent parasites such as fleas, ticks, mites and worms. Ivermectin and related drugs are among the most effective of these.
  • Ivermectin is a parasite control drug. Ivermectin causes neurologic damage to the parasite, resulting in paralysis and death.
  • Ivermectin has been used to prevent parasite infections, as with heartworm prevention, and to treat infections, as with ear mites.

Ivermectin as a Heartworm Preventive Medication in Dogs
Ivermectin is approved by the United States Food and Drug Administration (FDA) to prevent heartworm infections in dogs. Products containing Ivermectin are normally administered monthly for heartworm prevention and include medications such as Heartgard®, Iverhart®, Tri-Heart® and many other generic ivermectin-based heartworm preventive medications.

When used as a heartworm preventive medicine, ivermectin is used at much lower dosages than when used for other purposes. When used at the lower heartworm prevention dosages, ivermectin has a much lower potential for side effects than when used at higher dosages and this is the reason that ivermectin is approved for use as a heartworm preventive medication but must be used off-label (in a fashion not approved by the FDA) for many other purposes.

Read more at Suite101: Ivermectin for Dogs: Usages, Safety and Side Effects of Ivermectin in Dogs

Brand Names and Other Names

  • This drug is registered for use in animals only.
  • Human formulations: None
  • Veterinary formulations: Ivomec® (Merial), Zimectrin® (Farnam), Eqvalan® (Merial), Heartgard® (Merial), Iverhart® (Virbac) and various generic preparations

Uses of Ivermectin

  • Ivermectin is used to control skin parasites, gastrointestinal parasites and parasites within the bloodstream.
  • Ivermectin prevents development of heartworm disease in dogs and cats.
  • Ivermectin can be used in an extra-label manner to kill microfilaria (microscopic offspring) in heartworm infected dogs.
  • Ivermectin is not effective against tapeworms and liver flukes.

How Ivermectin Is Supplied

  • Ivermectin is available in 10 mg/ml and 2.7 mg/ml injectable form; 0.153 percent and 1.87 percent paste form; 10 mg/ml liquid oral form and 68 mcg, 136 mcg and 272 mcg tablets.
  • Heartgard Plus® and Iverhart® are available in various concentrations of ivermectin combined with pyrantel pamoate.

Dosing Information

  • Medication should never be administered without first consulting your veterinarian. The dose for ivermectin varies from species to species and also depends on the intent of treatment. General dosing guidelines follow.
  • For dogs: Dose is 0.0015 to 0.003 mg per pound (0.003 to 0.006 mg/kg) once a month for heartworm prevention; 0.15 mg per pound (0.3 mg/kg) once, then repeat in 14 days for skin parasites; and 0.1 mg per pound (0.2 mg/kg) once for gastrointestinal parasites.
  • For cats: Dose is 0.012 mg per pound (0.024 mg/kg) once monthly for heartworm prevention.
  • The duration of administration depends on the condition being treated, response to the medication and the development of any adverse effects. Be certain to complete the prescription unless specifically directed by your veterinarian. Even if your pet feels better, the entire treatment plan should be completed to prevent relapse or prevent the development of resistance.


While the sensitivity to this type of medication is not always guaranteed, the following breeds are most likely to be affected (although not every “sensitive” animal in the breed is affected):

  • Old English Sheepdog
  • English Sheepdog
  • Shetland Sheepdog (Sheltie)
  • Australian Shepherd
  • German Shepherd
  • Long-haired Whippet
  • Silken Windhound
  • Skye Terrier
  • Collie

Washington State University Veterinary School developed a DNA test for a mutant gene which produces adverse reaction to ivermectin and other medications in some dogs. They have discovered that 75% of Collies, 25% of Border Collies, 8% of Old English Sheep dogs, mixed dogs of these breeds, plus other breeds have this mutant gene.

It is also seen in mixed-breed dogs, older dogs that have experienced a blow to the head, puppies, dogs that have overdosed on similar types of drugs, or other central nervous system diseases that affects the blood-brain barrier. Treating dogs that are susceptible to ivermectin toxicity with parasitic medication should be only be done under a veterinarian’s supervision and with great caution.

For breeds predisposed to the disease, an autosomal recessive trait (MDR-1) gene has been identified that causes a defect in the p-glycoprotein multidrug transporter to the blood brain barrier. This allows the ivermectin to pass into the brain at low dosages thus causing toxicity. This trait may also cause toxicity from other related drugs and should also be avoided or used in lower doses in susceptible breeds.

Toxicity can occur in cats, although it is uncommon.

Symptoms for the dog may be acute or mild. Acute signs will become apparent within 4 to 12 hours of the drug’s administration. In mild cases, symptoms will occur between 48 to 96 hours after your dog has been treated. Such symptoms include:

  • Lethargy
  • Depression
  • Drooling
  • Vomiting
  • Dilation of the pupil
  • Loss of appetite (anorexia)
  • Difficulty controlling voluntary movement
  • Disorientation
  • Tremors/Seizures
  • Inability to stand
  • Blindness
  • Slow heartbeat
  • Respiratory distress
  • Coma

Unfortunately, ivermectin toxicity cannot be reversed. Therefore, it is best to make your pet comfortable and treat the symptoms to the best of your ability. If exposure has occurred within the past four to six hours, induce vomiting and/or administer activated charcoal for the purposes of minimizing absorption. Be on the lookout for signs of secondary complications.

Some or all of the following measures may also be recommended by your veterinarian:

  • Intravenous fluid therapy
  • Keeping electrolytes in balance
  • Intravenous nutritional support
  • Turn the dog over frequently
  • Appropriate bedding
  • Physical therapy
  • Ocular lubricants
  • Ventilator in case of respiratory distress
  • Heat support if body temperature is low
  • Fans if body temperature is high
  • If your dog can not stand up, urinary catheters may be needed
  • Medication for seizures if appropriate

Much will depend on the severity of the dog’s reaction, along with its initial overall health. It may take several weeks of dedicated care before the dog fully recovers.

There is a test available to check sensitivity to ivermectin. If your dog is one of the breeds that is prone to ivermectin toxicity, you might consider testing for it. If you decide not to have the testing done, be cautious about using ivermectin to prevent heartworm disease or for the treatment of mites.

In dogs with MDR 1 gene mutation, the following drugs should be avoided or used with caution:

  • Ivermectin
  • Selamectin
  • Milbemycin
  • Moxidectin
  • Loperamide
  • Acepromazine
  • Butorphanol
  • Vincristine
  • Vinblastine
  • Doxorubicin

I include all this scary stuff so you know what can go wrong when using ivermectin on your own to treat your pets. It’s the same ingredient used in the popular heartworm meds you can buy for cats and dogs, but I know someone whose dog died when she administered Zimecterin Gold, a horse wormer, to her dogs. I don’t know the particulars in her case — what breed her dog was, how much she dosed, etc. I offer this info so you know what can go wrong and are as informed as possible before going this route. I assume no responsibility. Zimecterin Gold contains ivermectin and praziquantel. The praziquantel kills tapeworms. I have used this product for several years on my cats and dogs with no ill effects (knock on wood). My dogs are mutts. But be aware of the hazards if you have any of the breeds mentioned above. Having several cats and dogs, this is a more affordable alternative for me. There are several generic versions of heartworm preventative on the market. I used to order them from PetShed out of Australia. That worked fine, too. However, I have a number of cats and dogs and even the generic version became quite expensive.

Animals at highest risk are very young dogs, multi-drug sensitive breeds, dogs that may be exposed to ivermectin-containing products for large animals and/or the feces of large animals (horses, cows, pigs) treated with ivermectin.

Zemecterin Gold comes in an oversized syringe with a dosage appropriate for horses. The plunger on the syringe is marked at 50 lb intervals. This is how I determine the appropriate dosage. One syringe treats approximately 1300 pounds and costs about $15.

You can also buy the cattle version of just plain 1% ivomec (without the praziquantel), but it requires a larger dosage ivermectin (1/10 of 1 cc per 10 pounds) and it tastes really nasty. So you need to mix it in something like orange juice or yogurt.

Note: Cats can experience ivermectin toxicity. A small percentage of cats (less than dogs) have a sensitivity  to it and will react adversely to Ivermectin. It’s very easy to overdose them. Safe dewormers for cats are not that much more expensive than ivermectin. Praziquantel and pyrantel pamoate are 2 that can be used with less risk and the most common ones you’ll find sold for cats.

From a reader: I use Ivermectin Horse for basic worms in all our adult dogs and pups over 8 wks (Golden retrievers)by mixing with corn oil 6-1 ratio and dosing at 1ml/15#.


  1. Mandy says:

    I have been fostering a dog since June 9, 2015. He’s been on the Ivermectin for over two months for demodex mange. He was also on steroids, which interfered with the meds he was on, therefore, he still has mange. I came home two days ago and Buck was not twitching whatsoever! Later that night I gave him his Ivermectin and the twitching started shortly thereafter. It seems worse than before now. I stopped giving him the Ivermectin and will never give it him again. I am wondering if I need to do anything for him. I’m making him get up and walk be he seems so frail and think. He seems to drink but I am beginning to give him PediaLite. Do you think there’s a chance he will recover?? I need any information you can give me.


    • isak says:

      Only time will tell on his recovery. It’s important that he drinks and eats. Have you contacted his vet for their input? They know him best. Did he have any other ailments that may be contributing factors?

      As for the mange, if you have Buck confined, you might try some oil on his mange to suffocate the mites. If he is able to lick the area, use a food grade oil like coconut oil or cooking oil.

  2. jana w says:

    Our dog a belgian shepherd received heartguard on a Thursday and by Sunday was blind, wed she was in a coma with tremors. She is now in icu in memphis and is begining to walk assisted for balance, can’t lap up food or water so getting iv fluids and syringe feed, today she wagged her tail and is still blind. I’ve been reading so many of your stories and has any ones dog blindness gotten better or their eating abilites?

    • isak says:

      There have been a wide variety of recovery where a lot depends on the dog and time. The folks at Memphis can tell you best, but don’t give up.

      Good luck and best to you both.

  3. Jessica says:

    I am a foster mom for an animal rescue. I recently took in a teacup chihuahua about 4 pounds. The sheltler gave all his routine shots and a heartworm preventative (ivermectin) in a super small dose. Within hours he had a severe reaction to it. He was whining like he was in pain. He couldn’t keep his balance when he walked. He acted like he couldn’t see and was twitching almost to the point of convulsions. I took him to the vet and he stayed in ICU on IV fluids for 3 days and 2 nights. He got better but the twitching can take several weeks to go aways.

  4. Champ-yellowlab says:


    My vet recently recommended Ivermectin 1% for my 4 months old yellow lab who has early stage or mange. Since we could not afford the regular vet visits, he recommended the dosage which would match exactly to this calculation
    “If you gave the 100 pound dog 1/10 of one cc for every 10 pounds, you would be giving him 10,000 micrograms. If you gave the 100 pound dog 1/10 of a cc you would be giving him 1,000 micrograms.”

    He was 42 pounds where we started off his treatment. Today is 10th day of his treatment with increased dosage of 3.0ml
    He is usually very energetic and playful but last 2 days he is very lethargic and doesn’t want to come out of his crate. what worries me is he has lack of co-ordination, his pupils are dilated and he doesn’t go inside the bedroom when its dark. He can’t figure out himself where to go when we play the ball. I am really concerned. The vet said it might be one of the many side effected of Ivermectin but he is still a puppy. Should I stop the medicine. I haven’t noticed any positive results with his Mange either.

    – Should I stop the Ivermectin?
    -Has anyone else experienced the same problem with pupils dilation and lack of energy? Can you please share your experience?
    -I am taking him to Vet tomorrow but we have already spent a lot of money cz they seem to talk us into any bullshit all the time and we ended up paying thousands for nothing in past. I don’t want to panic and admit him if this is temporary and going to go away on its own. Any suggestions would be greatly appreciated.

    Thank you!!

    • isak says:

      It sounds like he may be having a reaction to the Ivermectin. I would stop the treatments right away. Did your vet also recommend bathing your dog for the mange?

      Here’s one solution you might try:
      Mix 8 ounce bottle of 10% benzoyl peroxide (People) facial cleanser with 16-20 ounce bottle of dog shampoo. This will do for several baths. BENZOYL PEROXIDE BLEACHES JUST LIKE HYDROGEN PEROXIDE.

      Use ‘dog’ towels and blankets and remove the nice bathroom rug. Wear old clothes. Wet dog completely. Drain bathtub. Lather dog with a generous amount of benzoyl peroxide shampoo mix for 10 minutes. Give dog a shower for 10 minutes to rinse very carefully. Benzoyl peroxide opens the pores– mites live in the pores. Keep dog in tub. Add 1/4 cup neem oil to gallon of warm water in a bucket. If the dog is small and you can find a container that he fits in, do that inside of bathtub. Soak him for 5 minutes, massage well several times and he’s done. For medium to large dog, put each foot in bucket and massage solution into dog’s leg. Use a cup to pour over dog repeatedly trying to save as much as possible in bucket to reuse. Massage into the entire dog. Be careful of eyes. Use a sponge for the belly and face. Wash 5-10 minutes, depending on how big the dog is. Do not rinse off. Do not towel off. When he stops dripping, wrap him in a blanket and stick him in his kennel or a small warm spot. Keep dog warm until dry. All his pores are open; he could take a terrible chill. Bathe every week. He can have baths twice a week instead if it is really bad. Every 2-3 days, rub neem oil on afflicted areas, more often if he won’t stop chewing. It doesn’t matter if he licks it off after a few minutes. They make neem oil pills. If your dog also gets the skin yeast infections dogs can get with demodex, soak him in vinegar. No soap, no scrubbing, just a good soak. If he has a wading pool, add a gallon of vinegar to it. He soaks himself in it and that cures his yeast.

      Keep us posted.

  5. brandie says:

    My 7mo old yorkie got ahold of some horse wormer I caught it in time that she didn’t get a whole lot, but now she is acting like she is blind, and stumbling around,my question is, will she be able to pull through this?

  6. Margaret Schoonmaker says:

    Please keep in mind that dogs eat poop! Sometimes any and all kinds. If you live around horses, sheep or cows or any livestock or walk your dogs on trails used by horses your dog could be poisoned by eating poop from a recently treated animal. Even poop from a recently treated cat or other dog (I know – dogs can be gross 🙂

    Try these products for natural control of internal/external parasites and infections // Oil of Oregano is also a one stop pharmacy for humans, too! Read this book: “Your Guide to Oil of Oregano. Better Health for People and Pets” by Tracy K. Gibbs, Ph.D.

    Also, for dogs who have general seizures, not ones brought on by acute poisoning (although this may work for them, too) as soon as they start to seize place an ice pack on the middle of their back along the spine. Many times this shortens the seizure or sometimes stops it cold. Please see this website for help with seizures in dogs: //

    Our dog started having seizures at 6 months old, one right after another – long story short-we ended up taking him to one of the top veterinary university hospitals in the US and never once, even though I told them we had horses, did they ask if I had recently treated any of my animals with ivermectin or any other chemicals or medications. I cannot remember that far back if I even did treat anyone for worms (I use ivermectin paste de-wormers). Usually I write it on the calendar, but not always. I don’t know if that is what triggered the fits in our dog ( I guess I’ll never know because they had to give him drugs at the hospital or he would have died), but he is on meds now for the rest of his life, or until we can find some other way to keep him from having seizures.

    My point is that we need to think for ourselves and not rely on veterinarians (or doctors for that matter) to come up with what could be making our pets or ourselves sick and how to heal from illness or prevent it. I am not against vets or doctors at all – they certainly can’t know everything, but we are smart, too, and very capable of doing our own research and of taking a more active roll in the health of ourselves and our pets.

    I just happened across this website while researching “how long does ivermectin stay in horse manure” after reading an article on pharmaceutical pollution in our environment.

    I hope this helps pets and people!

    • isak says:

      Thanks for sharing the great info and your story.

      I think ivermectin poisoning from eating horse manure is one of those things you see clearly in hindsight, but don’t really think about beforehand even though it makes perfect sense that what goes in must come out.

      Have you heard about using canine cannabis for the seizures? From what I have read, people have had good luck with it. It’s legal to buy in the US because it does not contain THC. I lost my boy, Mobley, to seizures a few years back. Had I known about the cannabis then, I would have tried it.

      Again, thanks for your post. And best to your pup.

  7. Tina says:

    I have 2 saint Bernard pups at 6 weeks who I used cattle paste which I used on the other 4 as well and these 2 have head bobbing, disoriented, at times lethargic, one has a very stiff gait and loses balance at times his head is back and forth constantly. One seems to have problems closing his eye lids he has slight head bobbing, but is skin and bones I have him on nutri vite along with 2 big meals of mash a day combined with 4 cups of water at a time. They both are very small around 6 pds which the others are 20 plus pds. They were wormed a week ago today. They still play and eat and drink. How long can it reside in the body? Will they ever be okay? I never knew this about dogs with white paws as I treat all 8 of my pet saints with the same wormer.

  8. Gabe says:

    I gave my 10 year old Staffordshire terrior zimecterin 1.87% paste it was what I thought a very small dose within 12 hours she was completely blind having trouble walking its been about 18 hours now and she is not drinking water but has eating food anything I can do while its somewhat early to prevent damage or shorten the problem? ?

    • isak says:

      Keeping her hydrated is important. Maybe add some water to her food or give her pedialyte via an oral syringe. If you are unable to get her to the vet tonight, try some of the suggestions mentioned in the article for overnight, then contact your vet in the morning for their recommendations.

      Was this the first time she had ever had Zimecterin?

      Best to you both.

  9. Barbara says:

    ozone therapy my german shepherd is much improved. I am hoping for a full recovery. will keep you informed.

  10. jackie says:

    My dog was giving ivomec and she has all the symptoms mention above

  11. katina says:

    like the color of her eyes

  12. katina says:

    they gave her steroids and some antibiotics and some wormer that was it.

  13. katina says:

    no she is completely blind and not that I know of getting into anything no and she hasn’t had no head trauma, no meds, and she has a green glaze in her eye like the color you would see as if you took a picture of her, and there has been no improvement in her at all she is getting to be skin and bones.

  14. katina says:

    no she is completely blind and not that I know of getting into anything no and she hasn’t had no head trauma, no meds, and she has a green glaze in her eye like the color you would see as if you took a picture of her, and there has been no improvement in her

  15. katina says:

    I have a blue pit bull she was fine at first then she had her puppys there all fine but she went blind after haven them and now she want eat to drink do you think this could be wrong with her plz im just looking for some answers my vet couldn’t give me anything they don’t know whats wrong with her but im trying my best to find a answer about her and what could help her.

    • isak says:

      Did she experience any kind of head trauma? Is she on any medications? Could she have gotten into something? Is she completely blind or does she see shapes? Do her eyes look clear? Have you seen any improvement over the days since?

  16. Diane says:

    Please don’t administer Ivermectin to your dog without your vet testing for the MDR-1 gene, regardless of breed. We have a very sweet Bull Terrier who had a toxic reaction to this med, after receiving small doses for 5 days. We stopped the meds after that time because he was showing strange side effects. He stopped eating and drinking after a few days, had neurological issues (Back legs not working well), became lethargic, will not play, sleeps a lot. This was our sweet, beautiful, playful, happy puppy. After two weeks without the meds, he has recovered only a tiny bit. He has difficulty walking because of his neurological issues. He is eating, but we cook chicken, liver, etc. and feed him from our hands. He has an aversion to liquid, so he is not drinking enough. We put water into anything we feed him, to try and keep him hydrated. He seems like an old, old dog. if anyone has been through this and has any ideas for us, please share.

    • isak says:

      What a sad story. I am so sorry. I have heard that some dogs rebound with time. I hope your baby is one of them.

      What kind of ivermectin was administered (so others will know)?

  17. Cathy says:

    I have a Min Pin just turned 1 year. In March she was having myoclonic seizures. ..
    Nuro Vet put her on high doses of Prednisone & Antibiotics in case it was bacterial. Tested & only thing she came up with was immune mediated epilepsy, has kept her on this since March gradually stepping down. Still on 2.5 mg every other day & still .6 of Keppra 3 x day.

    Now she’s broke with Demo a mo. ago, especially feet. I’d tried LymDyp dips, Goodwinoil, nothing worked.
    My neuro saw this breakout, I asked for Mitaban & she wouldn’t prescribe as not her expertise. …so I asked about ivermectin, would it hurt her? She didn’t think so…so for 8 days dog has gotten 1/10 cc of ivomec, 1 x day.
    Today she’s threup, had a spell of shaking….even some watery clear poop….I’m terrified she’s having reaction to ivomec, but being still on Pred, mites will take over again. It appeared to start to get better.
    What can I do?

    • isak says:

      I’m sorry I have been out of pocket. If you get this, can you let me know how things are going with your Min Pin? As for the watery poop… sounds like there are a lot of chemicals going into her stomach. You should give her some probiotics/acidophilus to bring back the good bacteria.

  18. LaLa says:

    My 7 month old, 32 pound puppy was just put on ivermectin for demo mange. She is currently on her 4th day of treatment. My vet has me slowly upping her dosage for the next two weeks. Today I started her on .29 ml. She did not eat her breakfast yesterday, but ate her dinner, and she also did not eat her breakfast today. I’m still waiting for her to eat her dinner. Sometimes she has been known to skip meals, but I guess I’m more worried since she is on the medication. Should I be worried and call the vet, or attribute it to her sometimes finicky eating habits? Thank you!

  19. Doris says:

    My 80 pound lab was overdosed with 8cc of Ivermectin 38 hours ago and 30 hours ago presented signs of toxicity. Blindness, staggering. Still eating and drinking. Chances of recovery? Regain sight?

    Thank you

  20. Gail says:

    My dog was deliberately poisoned with what the lab screen shows as something like ivermectin. We are on a farm and also a Certified Safe Farm with our state- no, we don’t leave expensive drugs laying about like ivermectin or any other toxins.

    She is alive, after she was taken and lost for two days, found 2 miles away. She’s blind, can’t keep her balance (legs splay and she “knuckles”).

    I have a pretty good idea who did this, can’t prove it, but if she was fed a 6pk of heartworm meds, now I can see that she this was deliberate and the person I suspect would have valid reasons for having a lot of heartworm meds around. The worst part is I have to prove it (we have a home security system now) and the state statutes will do NOTHING about it.

    • isak says:

      OMG! This is so terrible. I hope she recovers.

      If you are in farm country, the ivermectin could have come from cattle-strength ivermectin which is sold in liquid form. It has a terrible taste, but that could be disguised with food. And would be much cheaper than a 6pk of heart worm meds.

      Best to you all!

    • pam says:

      gail did you dog recover? im so worried about my dog I just don’t know what to do. please I hope your dog recovered as does mine.

  21. Tiffany says:

    Help… I have 2 English Bull Terriers….and one working Australian Sheppard.
    Need to Ivermectin the 2 Pure Bred Bullies, but very afraid…. is this breed ok to treat?
    My male is 60 lbs…and my female 37 lbs.
    The Aussie is old…and is an outside working dog….we suspect that he is the carrier of Mange (Sarcoptic) and he will have to be treated with another medication…. but can I treat the 2 bullies with Oral Paste?

    • isak says:

      While the sensitivity to this type of medication is not always guaranteed, the following breeds are most likely to be affected:

      • Old English Sheepdog
      • English Sheepdog
      • Shetland Sheepdog (Sheltie)
      • Australian Shepherd
      • German Shepherd
      • Long-haired Whippet
      • Silken Windhound
      • Skye Terrier
      • Collie
  22. Jv says:

    My shepherd is 3 months old and was given a dose of ivermectin (1cc) because she had severe worm infestation. After administration, she got better.. She was very actve and had a very good appetite. A week after, she got a bit sick.. She had diarrhea, didn’t eat and she seemed very tired. The following day, she ate a lot( twice more than her regular diet). That evening she had a high fever with diarrhea. Brought her to the vet and was in iv treatment. The vet cant figure out what was wrong. She died 2 days after. . Can it be due to ivermectin?

    • isak says:

      I am so sorry for your loss. How very sad.

      It’s hard to say whether the ivermectin contributed to your puppy’s death without an autopsy, but it is possible. Are you sure about the dosage? In general, an adult dog is given 1/10th of 1 cc of the 1% ivermectin every 4-6 weeks. So 1 cc would be 10 times that amount.

      Do you have horses around where she may have eaten horse poop? As horses are often wormed with ivermectin, dogs have been getting sick when they eat the horse poop because of the overdose.

      Again, I am so, so sorry for your loss.

      • Jv says:

        We dont have horses or anyother animals around.. I figured maybe it was overdosed.. But how come she didnt show any symptoms in the early days.. In fact her health improved after she was given ivermectin. I used ivermectin b4 in all my dogs and so far i havent experienced any problem. After reading articles about it being fatal to herding breeds, i am considering the possibility.
        Thank you isak.. I hope u can help me figure it out..

        • isak says:

          I don’t know the particulars in your situation. Maybe it was something else entirely than ivermectin. You may never know. I use it for my dogs and have — knock on wood — never had a problem.

          I have a dog that recently had a reaction to organic neem dip for dogs, but none of his siblings did. Each dog is different with regard to their sensitivities. In Kelsey’s case, he has a different father than his siblings so maybe his sensitivity comes from his father’s genes? I’m sorry I can’t help you to figure this out more. I know how hard the loss is and it is only compounded when we don’t understand why or how it happened.

          Also, puppies and senior dogs seem to be more sensitive.

          Was she recently vaccinated? Vaccines have come under a lot of scrutiny in recent years due to reactions to them. Is that a possibility?

          • Jv says:

            Her last vaccination before the ivermectin was a month ago. Yeah, i totally get what you mean.. Its so frustrating.. I noticed that in the site where she was injected with ivermectin, theres a wound.. Some kindof lession. Have u encountered cases like it?

  23. Carol says:

    We had a similar experience with our young Boxer. He does have four white paws, which may mean he has the genetic sensitivity to Ivermectin …
    The vet prescribed a type of wormer that kills fleas, worms, and heartworms. Shortly after the fist dose, he became stiff, in was a lot of pain, could not lower his head and could barely walk. We thought he had injured his back while running/playing with the other dog. Vet thought same thing. Vet medicated with pain pills and he got better over the next couple of weeks.

    Three months later, I stupidly gave him another dose of the medicine.
    Within 24 hours of that dose, he became stiff. His front legs were very stiff, his shoulders and back was rigid and he could not lower his head to drink water. He had problems getting up. Overnight, he screamed, and I do mean a terrifying scream … he was in so much pain. I did not have any pain pills on hand … then I snapped that he did not injure his back, the wormer was acting like a neurotoxin. Since I’m an allergic person myself, it was midnight, and our Boxer was screaming in agony, I searched online and gave him a dose of my prednisone. Got him to the vet the next morning. Vet put him on an extended dose of steroids and pain medication. The steroids immediately “fixed” him.

    Three months later, it is now happening again. Can’t walk, stiff, dehydrated and in pain (I can see it in his eyes). I guess the toxin is still in his system and may have damaged him permanently. Only time will tell … started him back on prednisone today … he immediately (within 4 hours) began eating and drinking again. Will see the vet Monday morning.

    These pet medications are poisoning our animals. God forbid a child or person absorbed this stuff through their skin!

    • isak says:

      I have painted wood floors in my house. If a DROP of these meds falls on the floor, it immediately eats the paint off the floor! Yet we put it on our pets’ skin???

      Also, the adage that ivermectin is not for dogs with white paws is misleading. I have dogs with white paws that it did not bother. But I worry people might use these meds on their dogs who do NOT have white paws thinking their dogs are safe from ivermectin poisoning. This is not the case.

      There are cases, too, where people treat their horses with ivermectin paste. It passes through their digestive system and dogs are eating this highly dosed up horse poop and being stricken with a large overdose of ivermectin.

      Good luck with your Boxer. Did he just recently go off the steroids? Or is there some other reason you can think of that these symptoms have returned?

  24. Robin says:

    My dog, a cur/beagle mix was 2 years old in January. I adopted her last August and waited until her heartworm check in the Spring to start her on preventer. I chose heartguard with Ivermectin and her personality has changed. I am quite upset. One of the side effects, so you know, can be excitability. It is listed on the literature from the drug. She has started barking at people after they pet her and is more aggressive than she used to be. I am going to call the vet today. I have been observiing her for a month and don’t want to give her the second dose…or the others. Let me tell you, I am not happy. My dogs sweetness and her response to most humans made her an excellent candidate for therapy dog. Now? I read here and elsewhere that the effects can’t be reversed? That means nervous system damage that changes behavior can’t be reversed? I will let you know what my vet says. Thanks for posting this.

    • isak says:

      Please do let us know what your vet says. Sounds like she hasn’t been on the medication that long, so perhaps without it in her system, she can get back to normal and become a therapy dog.

  25. Sandra says:

    Also want to mention I live misquito heaven Florida (heaven for them that is)For me its hell.

  26. Sandra says:

    I have always give paste ivermectin to my small dogs,but I had a vetrinarian show me how much to give each dog and he really stressed the importance of being exact in dosing.Which for my 5lb Yorkie & 7lb Chihuahua is just a very tiny smear on the end of my pinky finger and my 15lb Lhasa Ahpso & 12 lb Chihuahua mix min pin size of top of pencil eraser.Been doing this for 5 years no problem and heart worm and fecal test negative.I do however have horses,but do not take my dogs to stables for at least 3 days after deworming horses.

  27. Paula says:

    I took my 9 yr old Fila mastiff to the vet after seeing the brown urine, lethargy and staggering gait etc., and after a truck load of money for blood a urine tests, the result was she has liver cancer. I asked her when I would know it was ‘time’ and she sent me home with a heavy duty medicine (denamarin) and told me to watch for her to stop eating completely. I nearly opted to have her put to sleep then, but my grandson was with me and I had to clear my head so I brought her home to keep her comfortable. Real long story short, 18 days later, she is back to normal. I believe she was misdiagnosed because her liver numbers were ‘off the chart’. The thing that makes me mad is, I had read these posts before going to vet.. (trying to find out what was going on and suspecting the heartworm plus medicine) and shared my concern of it being the heartworm med. My vet dismissed it! I will take her in again to get her new liver numbers when the medicine is gone, but I’m sure they will be good, as she is acting normal and her urine is clear. I’m so sorry to all of you who have worse horror stories. Please stop taking the heartworm plus… they should take it off the market. (she was slowly being poisoned to death..I noticed in August..6 days after treatment, she was ‘weird’ and noted it on my calendar ..then Sept. it was one day after treatment.. she was ‘off’ again.. Then this month 4 days after treatment, it was BAD. I don’t know why my vet is in denial of this drug being the cause. ) Sadly, most people won’t know about this site until they already have a serious problem!

    • isak says:

      I am so glad you decided to clear your head and waited. Look what you would have missed.

      In answer to your question, “when will you know?” The answer will come to you; your pet will let you know or it will become obvious. Many people will tell you that you should put them down and not let them suffer, yet we are unable to do this for people. Odd logic, in a way. But you will know when the time is right, trust me.

      Best to you guys!

  28. sydney says:

    I know this is about dogs but I lost my baby girl already to cancer in May (beautiful German Shepard/Rottweiler mix). So I have a cat now, a wonderful cat that my baby girl picked up at the vet’s office last October and I am trying to find information about how rare cats toxicity is to ivermectin (heartgard)…. In January this year we gave her Reviolution. Within two days she had a seizure. That contains Selamectin. So we decided to try heartgard and she appeared to do OK but it took her three or four days to eat the tiny pill. Twice, in July and at the beginning of September, she ate the entire pill in a matter of minutes…within a few days she had seizures. Did we get lucky the other five months because she took so long to consume the pill? We are desperate pet parents (all her tests came back OK for other issues) trying to figure out what is going on.

    • isak says:

      From the symptoms you describe, it sounds like your cat is receiving too much ivermectin for her particular body when you are giving her the whole pill at once. Can you give her the pill over several days? Maybe cut it into thirds or quarters and give her a piece every other or every third day?
      It seems to me that you were indeed “lucky” over the other five months. Are you sure she got the whole pill during those times when you say it took her days to finish a pill? Perhaps you kept giving it to her and she spit it out and this went on until she finally got the whole thing?
      Good luck and try smaller doses.

  29. Ashley says:

    My 6 week old American pitbull terrier was chewing on an empty tube of ivermectin horse wormer.There must have been a little left because now hes wobbly,drooling and seems blind.Hes still eating and drinking.Will it wear off?

    • isak says:

      Some dogs come through it just fine; some may retain some problems. But it takes time. Make your dog comfortable and treat the symptoms to the best of your ability. If you see anything that concerns you, take him to the vet immediately. That he is eating and drinking is a good sign.

  30. Dannielle says:

    I gave my puppy dewormer that petco advised me to use at about 6 int the eavning yesterday and last night she was shaking but i just thought she was cold and this morning we discovered that she is currently blind. she was still shaking and about mid day today she had a seizure. Is my puppy going to die? Is the blindness only temporary? Is there anything i can do to make this easier for her? She is not even a year old yet.

    • isak says:

      What kind of dog is your puppy? What was the name of the dewormer? Does it contain ivermectin? Given the blindness and her seizure, I recommend you see a vet as soon as you can. They can do an exam and tell you better than I can.

  31. Dan says:

    Same story here more or less, except the vet injected my Australian kelpie with the drug.
    He’s four days in, but we put him in the emergency this morning because he was shaking more than before and wouldn’t eat. We expect him home in a day or two, but how long will it take to see significant improvement? He can stand, piss, walk unsteady and shit, even wag his tail a little. He’s eight and in otherwise great shape.

  32. Theresa says:

    Hi..My daughter sent this article to me via fb in regards to a situation my mom had just experienced about 3 weeks ago. My mom had a long haired Dauchsand whom she had taken to the vets on a regular basis for well doggie check ups and such. Her next to last visit she took her on she was given Iverhart Max heartworm pills to take as a preventative. This was not the first time she had taken a preventative medicine for heartworms. About an hour after she gave her the Iverhart Max pill she noticed that her dog started throwing up and then started to get lethargic not being able to hold her head up or walk. She brought her to the vets and found that her heartbeat was very slow and faint. The vet also took a syringe full of fluid from around her heart. My mom had to put her down because she was in such bad shape. I was wondering what could have happened and if you have heard of any recalls or anything negative about the Iverheart max medicine?

    • isak says:

      First off, I am so sorry to hear of your mother’s loss.

      In general, Dachshund’s are not on the list of breeds that have problems with ivermectic, but that is not to say that she couldn’t have had a reaction to it. Only your vet can say for sure what caused her symptoms and subsequent death. But from the timing you mentioned, it does seem like the Iverhart Maxx may have had something to do with it. Have you asked the vet for their input?

      Was the dosage too high by some chance? Was she on heartworm preventative previously?

      There was a recall on one lot of Iverhart Max in March, 2012. But it seems it was for the 50-100 lb version.

      Virbac AH, Inc. announced a voluntary recall for one production lot of IVERHART MAX Chewable Tablets. The affected product is Lot #110482 (Large, 50.1 – 100 lbs).

      Again, I am sorry for her loss.

  33. Art says:

    Melissa, on October 11th, 2011 at 7:48 pm Said:
    My 5 month old puppy was diagnosed with demodetic mange. The vet gave him ivamec 2cc every day. The second day i noticed that his back legs began to get wobbly. Does he have ivamec posioning and if so what should i do and is there any thing else to cure demodectic mange?

    2 CC of Ivomec is a dose for a 200 pound dog and this was given to a puppy? Should use at 1/10 CC per 10 pounds. Need to use daily for 2 months or until hair grows back, for demo mange – works great. The Vet should be sued.

  34. christy skirvin says:

    i gave my shitzu some ivermrctin and it has made him very weak off balance,blind does anyone know how long this will last

  35. Megan says:

    The vet gave my 5 month old great dane Ivermectin for her mites starting out using 0.69mls and upping it every 2 days to 1.1mls, 1.4mls, 2.1mls and by the times we got to 2.8mls she was unable to walk,stand,move.. I called the vet and all they said was to stop giving it to her, when we took her into the vet she had to be carried on her bed and brought her in with a buggy, she would cry if we would touch her shoulder blades or hips, they put her on some pain meds which helped the pain but never once said anything about the ivermectin, we know that the ivermectin has poisined our puppy, it has been 3 weeks now since she has been off ivermectin and is still having lots of problems, she has some days where she will not move at all and some days where she will get up and move to another spot and not move again, she has alot of trouble going up stairs, standing,getting up, walking, pupplis are always dilated. she has a low appitie. Is there anyway that the ivermectin will wear off in time? We went to another vet and she said if its not out of her system by now then it never will, will she be like this the rest of her life??

  36. Thank you for all the info.
    Our mini Daschund , Spot was wormed with Heart Guard plus week 1 Wednesday, then I wormed 20+ horses with Ivermec, 4 with Ivermec Gold. Week two Friday.
    Friday PM Spot goes to the Barn with my husband, I am sure he ate horse poop whilst there.
    2.00am Sat morning we found Spot blind, with Dilated Pupils, rushed to emergency vet then the eye specialist vet.
    They recommended Neurologist, but we could not do the $3000 +.
    Felt very guilty but were already at $1200 in vet bills.
    One week later Spot appears to have his eye sight back and is almost back to normal.
    NON of the vets connected this to Ivermec, even when I asked if the heart guard plus could have been an issue.
    Spot is on these meds.
    Clindamycin 75mg
    Prednisone 7.5 mg
    Doxycycline 50mg

    • isak says:

      So happy to hear your news about Spot’s recovery! It’s truly a hard decision when money steps in. And truly a wonderful thing when they pull through it anyway. Guess Spot wasn’t ready to leave yet!

      How long will he be on the meds?

      Thanks for sharing your experience.

  37. emily says:

    Having worked for a Vet for many years and seeing the aftermath of using Ivermectin Horse Paste and Ivermectin 1% in dogs, I am still amazed at how many people tell us ” Well, the guy at the feed store said it would work just fine”
    or my favorite ” I know this lady that breeds dogs and she swears by it”. These statements always make me want to take out full page ads in the local paper
    that read “DON’T USE IVERMECTIN IN DOGS OR CATS UNLESS YOU ARE A VETERINARY PROFESSIONAL!!!!!!”, but I just can’t afford it. The basic facts are:

    horse paste is concentrated for large animals, not animals under 100 pounds.

    Ivermectin 1% used orally in dogs takes very small amounts which are hard if not impossible for the average person to measure for even medium sized dogs.

    Any dog may have the gene that makes them more likely to succumb to ivernectin toxicity.

    Ivermectin does not treat fleas or much of anything useful in dogs when applied topically, ( to the lady who applies the pour on to her Pom every month for heartworm, ironically the dog tested positive.)

    Before using any medication that is not labeled for the animal you are using it on consult a Veterinarian, not the guy at the feed store or the lady down the street. Use the internet and rely on reputable websites, not “sandy’s dog page .com.

    I say all this after having seen 6 cases this month and having next to no sleep from being up all night talking the guy through his dogs ordeal until he can get them to the office this morning.

  38. julie says:

    My dog[s] have had same symtoms as heart guard, after years of using it. My thought might be cat poop. Cats can receive heart guard too. My dogs do eat the stuff, and the throw up from my 8 year old vizsla smelled like poop. Didn’t think of horses. Staggering, drunken gait, finally couldn;t stand. Blindness shakey head, sensitive for light. Went on for 6 to 8 hours. Then all back to normal. One dog had a seizure[very small] after heart guard, she didn’t have one from Sept-Feb gave heart guard 4 days later bigger seizure. vet says it quickly goes out of their system. Read it comes out in poop. Mutiple cats in neighborhood?????

    • isak says:

      Pretty scary when we can’t confirm the source. How can you avoid it if you don’t know? Any cows in your area? They are also treated with ivermectin.

  39. cindy says:

    My American Pit Bull Terrier is at University of Florida Veterinarian School of Medicine right now being treated for Ivermectin poisoning. He had a sudden attack while on our walk. Signs were 1st slobbering/drooling (excessively) then diarrhea. I arrived at an animal clinic within 20 min where he then began vomiting and having seizures. Blood work showed elevation in Liver and Pancreas reading was 1256 He was given fluids and treated for what the Dr suspected was heat stroke after 6 hrs the Dr gave him Vit K injection. I then transferred him to Emergency Hospital for over night care where he was given more fluids and I was informed his temperature had risen significantly and at about 6am he was given charcoal. In the morning the Dr. recommended University of Florida. So I left immediately for UF. He had been on his side laid out flat for about 20 hours and when i put him in my car I noticed he wagged his tail slightly. During the drive he did raise his head in an effort to be upright! Upon arrival at UF his heart rate was critical. Meds to stabilizes heart/monitored catheter and IV fluids. Next day prognosis Ivermectin poisoning via ingesting Daily Feed Through Wormer in horse manure and or ingesting left over grain/wormer in stalls at night!!! I had NO IDEA the horse manure could be toxic. I remove feces from pastures everyday and of course the dogs ride in 4wheeler with me and once in a while I would catch them eating the manure. Its been 6 days now his organs show NO damage. He’s been taken off all support. He is eating and drinking and can stand to urinate. He can walk briefly then he starts to have tremors/shaking and wants to sit down. I’m hoping since everything has progressed for the better that eventually his Central Nervous System will recover enough so that he can have a normal life. Going to visit him today and possibly bring him home. I know that I’ll have to provide a lot of physical therapy so if anyone has any ideas I would great appreciate them.

    Sorry to be so long winded but I hope through my experience another dog will not suffer and will have a chance to survive. Please tell anyone you know that has horses and uses daily wormers that the manure is toxic!

    BTW the UF was absolutely wonderful!!! They let me stay in the Critical Care unit in the cage with my dog anytime I wanted. I was there off and on for 4 days and I never saw anything other than wonderful caring DR.s, students and techs!!! God Bless them all.

    • isak says:

      Once I read your comment, it makes sense that horse manure could be toxic and the dosage for a horse is so much greater than what I dog receives via heartworm meds, but I NEVER put the two together. And we know that lots of dogs eat horse manure. Thank you for sharing your story and our best to your dog! I am so happy to hear he is progressing so well!

    • Christen says:

      Hi there, I was wondering how your dog is doing now? I am currently at the Univeristy of Georgia waiting for my baby to pull through ivermectin posioning. He must have kicked up the tiny but that my horse dropped. I took him into the emergency room on Monday night when it seemed like he was hallucinating and they hooked him to an IV. The next morning I took him to my vet and they were concerned that he would go into respitory arrest and strongly recommended we go to UGA. It is not Sunday night and he has been there since Tuesday afternoon. He is a rescue and I was told that he is a lab/pointer mix but he has white paws. The doctors he suspect that he has the MDR-1 mutation and that is why he is taking so long to recover. They now have him off of a feeding tube since he is eating wet food on his own and they have him off the iv since he is drinking. He tried to stand up today with him supported his head against the cage. His tremors have gotten better but he still has them when stimulated. He is currently blind. The doctors are very confident he will make a full recovery, but I just was wondering if anyone else went through anything similar and if they would be willing to share. Thanks!

  40. Allie says:

    My Husband and I have breed dogs for close to 20 years, and this is the first time using this Medication on our 4 month old Mini Dachshunds. He gave them the dose that seemed to be correct. The Next day, One was near death and the other two were very sick as well. This medication, should not be used on dogs. One of mine died last night, and one seems to be blind. It is not worth the effect this could have on your dog and you as the owner. We of course have decide against using this medication on any of our pets. My husband spoke to a feed store owner today, and He too agrees. He also stated that many people purchase this to give to their Beagles. Please use Zimecterin Gold only on horses. This medication is no joke and causes a sad slow, death for the animals.

  41. Sarah says:

    I have a 5 months old Pitbull/German Shepard mix. He was diagnosed with Demadex Mange and was prescribed Ivermectin. He was on a low dose at first but then they increased it. After they did that we noticed his pupils dilated and the next day after another dose he became very ill. He is in the hospital now and he’s stable, but I am worried he will have permanent damage. I also question why the vet didn’t think to test him or take precautions since he has one of the sensitive breeds in him.

  42. Melissa says:

    My 5 month old puppy was diagnosed with demodetic mange. The vet gave him ivamec 2cc every day. The second day i noticed that his back legs began to get wobbly. Does he have ivamec posioning and if so what should i do and is there any thing else to cure demodectic mange?

  43. Kimberly says:

    I just adopted a lab/retriever mix from a local shelter 10 days ago. She has been put on ivomec teo days before we got her as a treatment for demodectic mange. She has spent the last two days in the vet hospital on IV ans steriod drip. She was falling over, deeply depressed, swollen eyes, etc. They also diagnosed her as heartworm positive, which I was told she didn’t have upon adoption. Poor baby. She’s only 2 years old. Will she ever get better? I fear not. Do dogs recover from this toxicity?

    • isak says:

      Your vet can best tell you, but many dogs overcome this.

      Dogs can sometimes have a reaction to ivermectin if they are heartworm positive or they can have a bad reaction to the ivermectin itself for various reasons. Right now, your vet is the best source of info on this.

      Best wishes, and please let me know how she does. Prayers to you both! And think positive! Think of many long years together once you get this behind you!

  44. Lee says:

    Our 12 yr old very healthy male golden retriever had a severe adverse reaction to Heartgard Plus three days ago. He had all the symptoms listed above (except seizure, coma, and death… so far anyway). He’s taken this stuff for years with only getting nausea in the past. He vomited within an hour but still (today) has dilated pupils, fear & paranoia, difficulty standing, and staggers like a drunken sailor. The vet only gave him some anti-nausea pills. She seemed incredulous that this was the cause. I can assure you, I watch my dogs very closely and this reaction was caused by the Heartgard. I can coax him to drink and eat boiled chicken but mostly he’s just laying around looking miserable (POOR BABY!).

    So… it’s not just collies and it’s not just “high” doses that can cause problems. I just hope he recovers from this because I can’t find anything (online or from the vet) that talks about possible long term damage.

  45. Celeste says:

    It is to notice Finnish Lapinkoiras can carry the MDR1 lethal mutation too. Recently one dog of this breed died in Canada from ivermectin.

  46. Opa Ohoyo says:

    I have a poodle schnauzer cross, Rosey, that had her 18th birthday in June. She averages 18-20lbs weight. I have been giving her 2/10 ml 1% IVOMEC [injectable-but dosed orally in dogs] since I adopted her at 6 months of age. In our South Central U.S. location I give this every 30 days year round. I was a veterinary assistant at the time I acquired old Rosey. This was the dose recommended by the very good vet that I worked for. I had several dogs at the time and it was most economical for me. I have never used anything else for parasite control on any of my dogs. They have all stayed healthy and lived long lives on it. This includes many purebreds as well as my favorite mutts. [no collies of course, but I did have one Aussie that was on it with no problems]. I now have two Jack Russell Terrier / Min Pin mix pups that are 9 months old which I have started on the IVOMEC. Rosey plays with them and they are all a lively bunch. We also have an Anatolian Shepherd Dog which weighs 110 lbs. He is on the 1% IVOMEC and gets 1 full ml every month. No ill effects for him either. Of course dogs should be heartworm free before begining this high a dosage, but keep in mind that too low a dosage is not 100% effective for heartworm prevention and does nothing for intestinal worms either. The dose in Heartguard is NOT effective on other [intestinal] parasites. Old Rosey has NEVER had any intestinal parasites and has had a clean [occult] heartworm test every year of her life as well as clean fecal exams. I attribute this, thanks to the IVOMEC, and her hearty mix-breed constitution to her longevity. I expect the old gal has several more good years in her yet!

    • isak says:

      Here’s to Rosey… and many more healthy, happy years! And to her playmates as well. Do you mix the 1% with anything to disguise the taste?

  47. Derek says:

    This is great information shared above and has enlightened me a great deal with regards to a situation I am going through with my dog right now. A few days ago I gave my dog her monthly dosage of HeartGuard a few days ago and within 30 minutes her rear legs were paralyzed. One more then the other. We ruhed her to the hospital and then to a Neurologist who tested her with an xray, catscan, myleogram, spinal tap, etc…everything came back relatively normal with the exception of a little swelling in the L3/L4 area of the spinal cord. We have her home no and are treating her with Prednezone daily. We feel very strong that this paralysis is attributed to the HeartGuard. My dog also had a liver shunt that corrected a little over a year ago and has not taken HeartGuard since that time due to the fact we lived in Las Vegas for a while and wasn’t necessary. 2 questions:

    1. Why is my Neurologist insistent that this wasn’t the cause of her partial paralysis?

    2. What are the recommended next steps?

    Thank you in advance for your feedback.


  48. Stan says:

    I have been using the 8gm/l ivomec for many, many years. Originally the vet told me to use 1ml per 10 kg (sorry I am from Ossie) and said it was a fairly strong solution which meant that if I was not accurate in my dates of administration, it would not matter, even if it was a couple of weeks late. The vet used to do a lot of volunteer animal relief work overseas where there was a crisis due to flooding etc. He told me that he used to take the ivomec himself to prevent getting stomach bugs in these under developed areas and he never got food poising or anything similar.

  49. Patrick says:

    our 2 month old mixed breed puppy overdosed with ivermectin.
    it was an over-calculation of the dosage for a puppy his size. an understood accident and human-error but still resulted in a very sad outcome.
    we saw him slowly loss his coordination and mobility.
    he is now paralyzed – he can’t stand up – he totally lost mobility.
    we’re deeply saddened by what happened to our little baby.
    my question is: is it still possible for him to recover from his paralysis? what are the chances that he’d be normal again?
    many thanks.

    • isak says:

      I don’t know about overcoming the paralysis. Given his young age, it seems that he might have the strength and vigor to overcome some of it. I am so sorry this has happened to you. Do you know what the dosage you used was and how you administered it so we can warn others? Your comment is a few weeks old (sorry. I’ve been away attending an ailing senior dog.). Has there been any change/improvement to his condition?

  50. Jo says:

    Your dosage for 1% Ivomec for heartworm prevention is incorrect. 1% Ivomec contains 10 mg/ml of ivermectin, or 10,000 mcg/ml. Ivermectin dosage for heartworm prevention in dogs is 2.73 mcg to 5.5 mcg per pound. Therefore a 100 pound dog would need between 273 and 550 micrograms of ivermectin. If you gave the 100 pound dog 1/10 of one cc for every 10 pounds, you would be giving him 10,000 micrograms. If you gave the 100 pound dog 1/10 of a cc you would be giving him 1,000 micrograms. 1/20 of a ml would give the 100 pound dog 550 mcg, but you can’t measure 1/20 ml accurately. To verify the information I am giving, look at a pack of heartworm preventative tablets to see how much ivermectin is in them. The 51 to 100 pound pack has 272 mcg in each tablet. That’s 2.72 mcg for the 100 pound dog. Yes, ivermectin is used at higher doses offlabel for other types of parasites, mange, etc. but not in collies and other breeds which might carry the gene. I am curious as to where you obtained your dosing recommendation.

    Reference: See footnote no. 4 at the bottom of this article:

    • isak says:

      The dosage came from several breeders and a few vets based on the protocol they have been using/recommending for years. I have used it for several years on my own dogs as well. I do not use it in the winter months so the dogs do not build up a resistance to the ivermectin. From what I have read, it is not necessary to administer heartworm preventative during non-mosquito season. I have also read that Heartgard is not necessarily a point of reference.

      You lost me in the middle of your math with this: If you gave the 100 pound dog 1/10 of one cc for every 10 pounds, you would be giving him 10,000 micrograms. If you gave the 100 pound dog 1/10 of a cc you would be giving him 1,000 micrograms.

      There seems to be a lot of latitude with the ivermectin dosage, however why administer more than is required. So I will do some new research based on new references I have and make any necessary adjustments. Many thanks for the info.

      • glenda martell says:

        My vet injected my sheltie with Pro heart 6 for heart worm + Milbemax tablet for other worms & within hours he could not stand & would not eat or drink for days, I used a seringe to give him water .It took weeks for him to recover.,but I was lucky. The vet had never herd of the collie breed being sensitive to ivermectin, so pet owners tell your vet.

What do you think?

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