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PetDosageChart

Antiparasitic · For Dogs

How much Ivermectin (Ivomec) can I give my dog?

Standard Ivermectin dose for dogs is 0.006 mg per kg (0.00 mg per lb), given once monthly (heartworm prevention) or as directed. Use the calculator below for your dog's exact weight, or jump to the weight-by-weight chart.

Onset
4-12 hours
Duration
30 days (heartworm prevention)
Class
Antiparasitic

Calculator estimate from Plumb’s Veterinary Drug Handbook. Not yet vet-reviewed — see our methodology .

This dosage information is for educational purposes only. Always consult your veterinarian before giving any medication to your pet. Dosages may vary based on your pet's health conditions, other medications, and individual factors.

Content reviewed by licensed veterinarians. Sourced from Plumb's Veterinary Drug Handbook and the Merck Veterinary Manual.

Dosage Calculator · 01

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By Weight

Ivomec dose by dog weight

Pick your dog's weight to jump to a dedicated page with the dose, frequency, safety notes, and FAQ for that size.

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Dosage Chart · 02

Ivomec dosage for dogs by weight

Scroll sideways to see full table

Weight Low Dose Standard Max Safe Frequency
5 lbs (2.3 kg) 0mg 0mg 0mg once monthly (heartworm prevention) or as directed
10 lbs (4.5 kg) 0mg 0mg 0mg once monthly (heartworm prevention) or as directed
15 lbs (6.8 kg) 0mg 0mg 0mg once monthly (heartworm prevention) or as directed
20 lbs (9.1 kg) 0mg 0mg 0mg once monthly (heartworm prevention) or as directed
25 lbs (11.3 kg) 0mg 0mg 0mg once monthly (heartworm prevention) or as directed
30 lbs (13.6 kg) 0mg 0mg 0mg once monthly (heartworm prevention) or as directed
40 lbs (18.1 kg) 0mg 0mg 0mg once monthly (heartworm prevention) or as directed
50 lbs (22.7 kg) 0mg 0mg 0.5mg once monthly (heartworm prevention) or as directed
60 lbs (27.2 kg) 0mg 0mg 0.5mg once monthly (heartworm prevention) or as directed
70 lbs (31.7 kg) 0mg 0mg 0.5mg once monthly (heartworm prevention) or as directed
80 lbs (36.3 kg) 0mg 0mg 0.5mg once monthly (heartworm prevention) or as directed
90 lbs (40.8 kg) 0mg 0mg 0.5mg once monthly (heartworm prevention) or as directed
100 lbs (45.4 kg) 0.5mg 0.5mg 0.5mg once monthly (heartworm prevention) or as directed
120 lbs (54.4 kg) 0.5mg 0.5mg 0.5mg once monthly (heartworm prevention) or as directed
150 lbs (68 kg) 0.5mg 0.5mg 1mg once monthly (heartworm prevention) or as directed

Common Uses · 03

What is Ivomec (Ivermectin) used for in dogs?

heartworm prevention mange (demodectic/sarcoptic) ear mites intestinal parasites

Administration · 04

How to give Ivomec to your dog

For heartworm prevention, give once monthly at the prescribed dose. Always test for heartworm before starting prevention. CRITICAL: certain breeds (Collies, Australian Shepherds, Shetland Sheepdogs, and related breeds) carry the MDR1 gene mutation and can suffer severe toxicity from standard ivermectin doses. Have your dog tested for MDR1 before using ivermectin.

Available Forms

tablet, chewable, injectable, topical

Give with Food?

Yes — give with food

Side Effects · 05

Side effects of Ivomec in dogs

Common side effects

lethargy
decreased appetite
vomiting
diarrhea

Serious side effects — call your vet

  • ivermectin toxicity (MDR1 breeds)
  • ataxia
  • blindness
  • seizures
  • coma

Emergency · 06

When to call the vet

Call your vet immediately if your dog shows any of these signs:

  • Staggering or loss of coordination
  • Dilated pupils or apparent blindness
  • Tremors or seizures
  • Excessive drooling
  • Collapse or unresponsiveness

For Cats

Looking for Ivermectin dosage for cats?

View the Ivermectin dosage chart and calculator for cats.

Related · 08

Related medications for dogs

Sources · 09

Sources & references

The dosage information on this page is compiled from the following veterinary and pharmaceutical references:

  • Plumb's Veterinary Drug Handbook — the standard veterinary pharmacology reference used by veterinarians worldwide.
  • Merck Veterinary Manual — a trusted, peer-reviewed resource for veterinary professionals and pet owners.
  • DailyMed (FDA Drug Labels) — official FDA-approved drug labeling and prescribing information for Ivermectin.

Read more about our methodology and how we calculate dosages.

Transparency · 11

How this page was made

Sourced from Plumb's Veterinary Drug Handbook, the reference used in US vet schools. Every dose, frequency, and tablet count on this page is generated from that data, then checked against the published references below.

Sources cited
  • Plumb's Veterinary Drug Handbook
  • Merck Veterinary Manual
Calculator formula
Doses scale linearly from a standard basis of 0.006 mg per kg (0.00 mg per lb) of body weight, given once monthly (heartworm prevention) or as directed. The calculator multiplies that basis by your dog's weight and rounds to the closest available tablet size.
Last-reviewed status
Automated from Plumb’s, not yet vet-reviewed.

More on our methodology and editorial process — how we source, calculate, and review dogs dosage data.

Frequently Asked · 07

Questions about this medication

Is ivermectin safe for all dogs?
No. Dogs with the MDR1 gene mutation (common in Collies, Australian Shepherds, Shetland Sheepdogs, and related breeds) can suffer severe, potentially fatal toxicity from ivermectin. A simple genetic test can determine if your dog carries this mutation. At heartworm prevention doses (very low), ivermectin is generally safe for most breeds.
How much ivermectin do I give my dog?
For heartworm prevention, the dose is 6 micrograms per kilogram (0.006 mg/kg) given once monthly. For mange treatment, much higher doses are used (0.3-0.6 mg/kg daily), but these should ONLY be given under direct veterinary supervision due to the risk of toxicity.
What breeds cannot take ivermectin?
Breeds with the MDR1 (ABCB1) gene mutation are at risk. This includes Collies, Australian Shepherds, Shetland Sheepdogs, Old English Sheepdogs, English Shepherds, and mixed breeds with these heritages. However, not all individuals of these breeds carry the mutation — genetic testing is recommended.
What are signs of ivermectin toxicity in dogs?
Signs include excessive drooling, dilated pupils, blindness, tremors, staggering, disorientation, seizures, and coma. Symptoms can appear within 4-12 hours of ingestion. If you notice any of these signs, seek emergency veterinary care immediately.

Safety · 10

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