How to treat parasites in dogs with ivermectin

Updated April 17, 2017

Ivermectin, also known as Ivomec, Heartguard, Iverhart Plus, Tri-Heart Plus and Acarexx, is an antiparasitic drug used to treat a variety of parasitic infections in dogs, including intestinal worms, mites and lice. Its most common uses are for prevention and treatment of heartworm, treatment of ear-mite infections and treatment of different types of mange. It has only been FDA approved for the prevention of heartworm. Its other applications, which can require a dose up to 50 times higher than that needed for heartworm prevention, are off label.

Have a veterinarian diagnose the exact type of parasite that has infected the dog. The dosage and form of Ivermectin prescribed will depend on the type of parasite to be treated.

Have your vet test for Ivermectin sensitivity. Some dogs, especially collies, Shetland sheepdogs, Australian shepherds and Old English sheepdogs, have a genetic predisposition to Ivermectin sensitivity, which can cause severe, even fatal side effects if a large enough dose is given to these dogs. The vet can determine if your dog has the sensitivity through a DNA test or through the administration of a low dose, followed by observation of possible side effects. These tests, however, may be skipped if Ivermectin is being prescribed for the treatment of heartworm, as this requires an extremely low dosage that is usually tolerated even by sensitive dogs.

Administer Ivermectin to your dog exactly as prescribed by your veterinarian.

Watch for possible side effects associated with your dog's ingestion of Ivermectin. Look especially for dilated pupils and an unsteady gait, as these can be signs of a reaction that may progress to respiratory paralysis and death. Contact your veterinarian if side effects appear.


Ivermectin, except when being administered in the extremely low doses used for heartworm prevention, may have a dangerous interaction with tranquillisers and monoamine oxidase inhibitors. It therefore should not be combined with valium, related tranquillisers, Amitraz (Mitaban©) dips or Amitraz tick collars (Preventic© collars). Spinosad (Comfortis®) is another drug that is dangerous to give in conjunction with Ivermectin. It increases the possibility of side effects.


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About the Author

Mildred Millhouse specializes in topics related to pet care, health and medicine. She has a B.A. in philosophy from Columbia University and is pursuing a master's degree in psychology.