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What is Parasitic Drug (Ivermectin) Poisoning?

Poisoning by use of ivermectin is well documented. Most cases of adverse reaction result due to overdose of the product, and toxicity due to sensitivity because of a genetic mutation, MDR1 (multi-drug resistance gene), specific to certain breeds. This medication is given orally (tablets, treats, liquids, pastes), by injection, and as a topical solution against mites. Signs of poisoning are many and include blindness, tremors, and uncoordinated movements as a result of nerve and brain toxicity . There is no treatment for the poisoning; supportive measures are the only care available (though in cases of oral administration inducing of vomiting and active charcoal use are often done). Early and aggressive supportive care allows for a good prognosis for recovery.

Ivermectin is used in the treatment of parasitic diseases, one of the most well known being heartworm disease. Ivermectin belongs to the avermectin family of drugs and has been approved for multiple uses. Toxicity has been documented, with adverse effects due to the cross between the blood brain barrier.

Parasitic Drug (Ivermectin) Poisoning Average Cost

From 57 quotes ranging from $500 - $8,000

Average Cost

$4,000

Symptoms of Parasitic Drug (Ivermectin) Poisoning in Dogs

Symptoms of ivermectin poisoning can appear approximately within 5 hours to 24 hours after the administration of the drug.

  • Dilation of pupils
  • Abnormal reflex of pupils
  • Vomiting
  • Abnormal behavior
  • Difficulty breathing
  • Confusion
  • Weakness
  • Lethargy
  • Stupor
  • Low body temperature
  • Hypersalivation
  • Loss of body control
  • Inability to stand
  • Respiratory collapse
  • Seizure
  • Death

Types

Poisoning will occur as a result of overdosage, as well as sensitivity to the drug due to the MDR1 genetic mutation. Breeds documented as having a predisposition to this problem are as follows.

  • Collie
  • Old English and Shetland Sheepdogs
  • Australian, English, and German Shepherds
  • McNab
  • Silken Windhound
  • Long Haired Whippet
  • Herding breed cross
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Causes of Parasitic Drug (Ivermectin) Poisoning in Dogs

Administration error (for example, an owner gives part of a tablet meant for a larger dog to their smaller dog)

  • Doubling up of a missed dose
  • Drug interaction with another medication
  • MDR1 mutation in susceptible breeds
  • Licking off of topical solution by your pet, or licking the solution off of an animal housemate
  • Use of livestock ivermectin on domestic animals
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Diagnosis of Parasitic Drug (Ivermectin) Poisoning in Dogs

The sooner the symptoms of poisoning appear, the more serious the toxic effects will be. If you have given your pet a treatment of ivermectin, if he has accidentally ingested the drug, or if you have administered a topical dose and see signs that show he is suffering from toxicity, immediate veterinary care is essential. Take your canine companion to the veterinarian or emergency clinic right away, bringing the drug packaging if available. 

Diagnosis will be based on clinical signs, the first symptom often seen is dilated pupils. There is no test available for ivermectin poison confirmation other than the serum ivermectin concentration found in the blood. Test results are not always immediate; therefore, action will be taken most likely before the results are known.

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Treatment of Parasitic Drug (Ivermectin) Poisoning in Dogs

The veterinary team will begin supportive care immediately which may include treatment for shock, intravenous fluids, eye lubrication, and corticosteroids. In some cases, active charcoal will be used in an attempt to bind the poison together for quicker expulsion from the body. Gastric lavage will be done if deemed helpful and appropriate.

A diagnosis of ivermectin poisoning will mean a hospital stay for your canine family member. As the effects of the toxin can be quite severe, a lengthy stay is typically the case. It is not unusual in the first hours and days of treatment for a canine to have a decline in health as the toxins take more effect, and then a gradual improvement as the therapy enables your pet to improve. During the hospital stay, the veterinary team will work to ensure that your dog is as comfortable as possible. Clean bedding will always be in place, and the team will move your dog’s position regularly to aid in his well-being. 

Your pet will probably be sedated for much of the time as he recovers because there may be a need for medication to control seizures or tremors, for example, and it is not uncommon for treatment to include mechanical ventilation in serious cases. Studies have shown that many canines will have effects like recumbency (periods of complete rest), coma, seizure, and inability to eat or drink, among other effects before recovery takes place. The recovery can be very slow, meaning weeks to months, before your pet returns to normal.

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Recovery of Parasitic Drug (Ivermectin) Poisoning in Dogs

When your dog is released from the hospital, he may need extra care from you at home as he recovers. Many dogs will have a convalescence stage of several weeks to months as they improve in health. Your veterinarian will be available and willing to assist you in many ways as you take care of your beloved family member.

It is crucial to note and remember that when using the drug ivermectin, advice and monitoring by your veterinarian is paramount. Not only is there the concern of the poison, there are other complications to be mindful of in regards to the use of ivermectin. Allergic shock is possible because if the ivermectin kills heartworm larvae that are present in the dog, the sudden death of the larvae can cause a reaction. As well, if there are heartworms present in a pet, and ivermectin is administered, the dead parasites can remain in the arteries and heart, causing an obstruction. This is why a heartworm test must be done before administration and if they are found they must be removed with another medication first.

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Parasitic Drug (Ivermectin) Poisoning Average Cost

From 57 quotes ranging from $500 - $8,000

Average Cost

$4,000

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Parasitic Drug (Ivermectin) Poisoning Questions and Advice from Veterinary Professionals

Need pet health advice? Ask a vet

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Ask a Vet

dog-name-icon

Diesel

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Boston Terrier

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1 Year

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Serious severity

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3 found helpful

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Serious severity

Has Symptoms

Shaking
Blindness
No Balance
Vomitting,
Traumatised

Brought my dog to the barn like every other day. A horse was just dewormed and dropped a few little drops to the ground. My dog was fine and about 2-3 hours later we went for a car ride. We got back home from the car ride and his eyes became huge and were all foggy (they were a blue-ish color). He was completely blind. He had a hard time walking and standing up. He was shaking a lot. We brought him to the hospital not to long after and even the vet told us she has never seen that! She made us bring him back home and told us to to go to a Ophthalmologist. I called them and they told me that the treatment was new and barely used. He seems to be calming down by just being at home. He ate this morning and took a little walk to pee. He still can't see. What are his chances of his eye sight to come back?

Sept. 10, 2018

Diesel's Owner

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Casper

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Rottweiler

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2 Years

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Fair severity

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2 found helpful

pill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filled

Fair severity

Has Symptoms

My dog is suffering from ivermectin bolus drug of 100mg which he ate last night,he vomited after having his dinner and in the morning when I saw him, his colours were different can you tell what king of blindness this drug causes? Is it cataract or glaucoma? Am scared please help him in every possible way please tell me what are the treatments available for it.

Aug. 22, 2018

Casper's Owner

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Dr. Michele K. DVM

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1611 Recommendations

If Casper has had an overdose of Ivermectin, he needs medical attention immediately. He will need to have supportive care while his body gets rid of that drug, and the blindness is from a reaction to the medication.

Aug. 22, 2018

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Roux

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pit mix

dog-age-icon

6 Years

pill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filled

Moderate severity

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0 found helpful

pill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filled

Moderate severity

Has Symptoms

Aggression

Our dog overdosed on ivermectin about 5 years ago and has now started showing signs of aggression towards our cat. Is it possible that she has some sort of brain damage caused by the overdose that would cause her to have random aggressive outbursts?

Aug. 16, 2018

Roux's Owner

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Dr. Michele K. DVM

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1611 Recommendations

It is unlikely that an episode 5 years ado would cause lingering aggression now, and more likely that as Roux ages, she is changing behavior. Since this seems to be a new behavior, it would be best to have a trainer work with her to stop this behavior before it becomes dangerous to your cat. If you do not know of a trainer, I'm sure your veterinarian can recommend someone for you.

Aug. 16, 2018

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gypsy

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Great Dane

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13 Years

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Moderate severity

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0 found helpful

pill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filled

Moderate severity

Has Symptoms

Loss Of Balance

Have a Great Dane Female 13 yrs Age had given her ivermectin 0.6ml SC 3 days back now she is not able to stand up on her own once standing she looses balance and she has no control on her urination or defeacation she has a good appetite and eating well she does have some tremors she had a similar episode 7 months back at which time she had labrynthitis and had got cured with steroids, antibiotics and also post that episode she does not gain any weight though her diet and appetite are good pupils left side seems to be dilated she is around 30 kgs of wt now priorly she used to steady at around 38-40 kgs what else needs to be done for her and how long would she take to recover if at all it is due to ivermectin have given her ivermectin prior to this without symptoms

July 22, 2018

gypsy's Owner

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3320 Recommendations

Ivermectin is available in different injectable forms and the number of mg/ml are important; however if we take that there was 10mg/ml we know that if 0.6ml was administered Gypsy would have received a dose of 6mg, dosage at 0.2mg/kg would have come to 8mg for a 40kg dog so she wasn’t overdosed and Great Danes are not a breed susceptible to ivermectin. In this case, you should visit your Veterinarian for an examination as I’m not sure whether the ivermectin is related or not and don’t know if the medication was stored correctly. Regards Dr Callum Turner DVM

July 22, 2018

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Bo

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Labrador Retriever

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11 Years

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Mild severity

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0 found helpful

pill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filled

Mild severity

Has Symptoms

Lethargy
Nausea

I had a very large lab. He was 11 years old. He had been slowing down and having some trouble with his back legs as would be expected given his age and weight. I gave him his heartworm treatment after testing Valuheart (ivermectin) 320 mcg as he is 122 pounds. He became ill a week after first treatment. Lethargy, inability to walk, and nausea. He got better with pain medication. I gave him his second dose the next month, same symptoms 4 days afterwards. He Continued to have spells intermittently for the past two months but would always get better with pain medication. Required steroids at one point. Just need to know if there was any relationship between the medication and his decline and eventual death. Also had multiple tumors they believe to be lipoma. Very large abdominal Lipoma. Thank you for any assistance

June 20, 2018

Bo's Owner

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3320 Recommendations

Ivermectin is safe for use in many breeds especially at the dosages used with Valuheart, some breeds of dogs have a genetic sensitivity (MDR-1) to ivermectin but Labrador Retrievers are not on the list (unless crossed with a susceptible breed. I cannot say with any certainty whether the Valuheart was or wasn’t a contributing factor to Bo’s death. Regards Dr Callum Turner DVM www.valuheart.com/uploads/TDS_VPValuheart_11.04.12.pdf www.petpoisoncontrol.com/portfolio/ivermectin/

June 21, 2018

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Penelope

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Goldendoodle

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1 Year

pill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filled

Moderate severity

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Moderate severity

Has Symptoms

None

My not even 2 year old dog Penelope Irishsetter golden doodle mix recently passed away. She had 6 trihart plus Chewable tablets ivermectin136mg/pyrantel 114mg Each ..she weighed 45lbs. Could there be a correlation between her ingesting the Chewables and then her passing 7 days later to what look like was a seizure. She threw up her food 5 different areas of my house?

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Axle

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Australian Shepherd

dog-age-icon

2 Years

pill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filled

Fair severity

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0 found helpful

pill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filled

Fair severity

Has Symptoms

Seizures

Hello, I have a 2 year old australian Shepherd that I tested for mdr1 and his results show he is N/M1. Everything Ive read said he "could" have a reaction to ivermectin and or other associated drugs. I also have horses and a pasture full of manure. I am needing to worm the horses and have concerns about how long the ivermectin could remain in the poop since he enjoys the occasional horse apple. Any idea how long I should keep him off the pasture and once the manure dries and composts is the ivermectin still present? Thanks in advance..

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Henry / Rico

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mini fox terrier x jack russell

dog-age-icon

7 Years

pill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filled

Serious severity

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0 found helpful

pill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filled

Serious severity

Has Symptoms

No Symptoms Yet

I have 2 mini fox terrier x jack russells that had heart worm injections in June. My daughter got the dogs immunized again for heart worm today, 4 months after the first injection and now I am worried that they will be overdosed. Should I be worried?

dog-name-icon

Charlie

dog-breed-icon

Shepherd

dog-age-icon

10 Years

pill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filled

Serious severity

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0 found helpful

pill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filled

Serious severity

Has Symptoms

Seizures

My dog suffered 4 seizures within 24 hours of ivermectin dose. He is recovering with anti-seizure medicine but continues to have small tremors and weakness in back legs. My vets are determined that the ivermectin could not have caused these issues and suspect a brain tumor. (He had similar reactions to drug Simparica two years ago but made a full recovery.) Could ivermectin be causing his tremors one week after dose? He did not overdose, but he is a Shepherd mix.

dog-name-icon

Bizzy

dog-breed-icon

Border Collie

dog-age-icon

2 Years

pill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filled

Mild severity

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0 found helpful

pill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filledpill-rating-filled

Mild severity

Has Symptoms

Seizure

My dog bit into a topical flea treatment containing ivermectin. She’s a border collie. I don’t think much came out but it was obviously a horrid taste as she ran around wiping her mouth for some minutes afterwards. I rang my vet straight away and they said to keep an eye on her but she should be ok. 10 days later she had a seizure (the first that we are aware of) while running around on her walk. Is it possible that this is connected? My vet says not.

Parasitic Drug (Ivermectin) Poisoning Average Cost

From 57 quotes ranging from $500 - $8,000

Average Cost

$4,000

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