If a dog eats ivermectin, especially in large amounts or if they have a genetic sensitivity (like Collies), they can suffer severe neurological signs, including disorientation, tremors, blindness, seizures, coma, and even death; common symptoms are drooling, vomiting, weakness, dilated pupils, and lack of coordination, requiring immediate veterinary attention as it's a medical emergency.

Is ivermectin toxic to dogs?

Given at the proper doses and under the supervision of a veterinarian, ivermectin is safe for most dogs and is very effective in treating and preventing a number of parasites. However, a dog with the mutation who ingests the drug can have a severe, life-threatening reaction called ivermectin toxicity.

How long does ivermectin toxicity take to show in dogs?

Ivermectin Toxicity

After ingestion, initial symptoms can begin to develop within 4 to 12 hours, while more gradual clinical signs may take up to 2 or 3 days to appear. Ivermectin can cause neurological damage and potential seizures. Common signs to watch out for include: Seizures.

What is the antidote for ivermectin in dogs?

However, if your dog has already developed any neurologic signs, such as disorientation, tremors, or seizures, induction of vomiting or administration of activated charcoal is no longer considered safe due to the risk of respiratory aspiration. Unfortunately, there is no specific antidote for ivermectin toxicity.

Which dog breed is sensitive to ivermectin?

Recognizing that the collies and other herding breeds that were sensitive to ivermectin were similar to the mdr knockout mice, Dr. Katrina Mealey at Washington State University, College of Veterinary Medicine, demonstrated that a deletion mutation of the mdr gene was present in ivermectin-sensitive collies (2).

How to Give Ivermectin to Dogs Safely: Correct Dose & 4 Dangerous Mistakes

Can I give my dog ivermectin from Tractor Supply?

Ivermectin is an important part of a parasite control program for certain species and should only be given to animals for approved uses or as prescribed by a veterinarian in compliance with the requirements for extra-label drug use.

Can I put ivermectin in my dog's food?

Ivermectin is available as tablets, chewable tablets, a topical liquid (for ear mite treatments), and an injectable that your veterinarian administers. It may be combined with other deworming medications. It may be given with or without food.

How quickly does ivermectin react?

Medically reviewed by Kristianne Hannemann, PharmD. Last updated on Nov 25, 2025. Ivermectin begins killing certain parasites within hours after administration, but symptom relief and full parasite clearance may take several days to weeks depending on the infection and individual response.

How is ivermectin cleared from the body?

Ivermectin is metabolized in the liver, and ivermectin and/or its metabolites are excreted almost exclusively in the feces over an estimated 12 days, with less than 1% of the administered dose excreted in the urine. Following oral administration, the half-life of ivermectin is approximately 18 hours.

What dogs can not have ivermectin?

Dogs that cannot have ivermectin, or are at high risk for toxicity, are primarily herding breeds (like Collies, Australian Shepherds, Shelties) with the MDR1 gene mutation, which impairs their ability to clear the drug, making high doses dangerous. Other sensitive breeds include German Shepherds, Old English Sheepdogs, and Long-Haired Whippets, though mixed breeds can also carry the mutation, requiring caution and potential genetic testing, as even small amounts can cause severe reactions. Doses in heartworm preventatives are usually safe, but higher doses (like for mange or equine wormers) are very risky. 

How much ivermectin is toxic to a 20 lb dog?

– For most dogs signs of toxicosis may be seen at doses greater than 2 mg/kg (0.9 mg/lb). Dogs affected by genetic sensitivity can have toxicosis with as little as 0.1 mg/kg (0.04 mg/lb).

What parasites will ivermectin get rid of?

Ivermectin kills various parasites, primarily roundworms (nematodes) like those causing strongyloidiasis, onchocerciasis (river blindness), ascariasis, hookworm, and whipworm, as well as ectoparasites like mites (scabies) and lice, by paralyzing their nerve and muscle cells, causing them to die. It's used in humans and animals for various infestations, though formulations and off-label uses differ, and animal versions can be toxic to people. 

What is the dog version of ivermectin?

Tri-Heart Plus (ivermectin/pyrantel) is a proven, cost-effective and easy-to-administer chewable tablet that helps keep your dog free of heartworm and other dangerous parasites.

How many times can I give my dog ivermectin?

Ivermectin is given monthly for heartworm prevention, daily or every other day for demodectic mange treatment, and every week or couple of weeks for most mites. If a dose of heartworm preventive is accidentally forgotten, it is important to give it as soon as it is remembered.

How is ivermectin metabolized in dogs?

Ivermectin is metabolized via oxidation in the liver and excreted in the bile to the feces; less than 5% is excreted in the urine. Its half-life in dogs is approximately 2 days.

Is ivermectin used as a dog dewormer?

Ivermectin is a very commonly used wormer, suitable for horses, cattle, sheep, birds, and a wide range of small mammals. It is occasionally used in dogs – but never in collies and other herding breeds.

Is Heartgard just ivermectin?

Yes, Heartgard contains the active ingredient ivermectin (in combination with pyrantel in Heartgard Plus) and works as a monthly preventative for heartworm disease, as well as treating/controlling hookworms and roundworms in dogs and cats. The ivermectin kills heartworm larvae before they can mature, protecting against the disease, and the medication requires a veterinary prescription.

What is the alternative to ivermectin for dogs?

Selamectin is a closely related cousin of ivermectin. It is designed for broad coverage of small animal parasites and will protect dogs not only against heartworm but also against ear mites, sarcoptic mange mites, ticks, and fleas. Cats are protected against heartworm, fleas, ear mites, roundworms, and hookworms.

Do vets prescribe ivermectin?

Ivermectin is an important part of a parasite control program for certain species and should only be given to animals for approved uses or as prescribed by a veterinarian in compliance with the requirements for extra-label drug use.

What is the 7 second rule for dogs?

The "7-second rule" for dogs is a simple test to see if pavement is too hot for their paws: press the back of your hand to the ground for seven seconds, and if it's too hot for you to hold comfortably, it's too hot for your dog's paw pads, which can easily burn on surfaces like asphalt, concrete, and even artificial turf. This helps prevent paw burns by prompting you to walk during cooler times (early morning/late evening) or stick to grass, as tarmac can get extremely hot even on moderately warm days.
 

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