Safety and Side Effects of Ivermectin for Dogs

You may not be familiar with the ingredient ivermectin, but it’s widely used as a worming treatment for dogs and can be found in some heartworm prevention medications. In this post, we’ll go over what ivermectin is and how it works, plus tell you about which dogs might have trouble taking it and what to do if your dog gets an overdose of ivermectin.

Ivermectin is a veterinary drug used in dogs to kill internal and external parasites.

Ivermectin is a veterinary drug used in dogs to kill internal and external parasites. It’s not a heartworm medication, so if you have a dog who needs protection from heartworms, talk to your veterinarian about what you should use instead.

Ivermectin is safe when used as directed. It is safe for dogs and cats, horses, rabbits, livestock and humans; birds may be affected by the drug as well.

Ivermectin does not kill heartworms.

Ivermectin is an oral medication that effectively treats and controls fleas, ticks, mites and intestinal parasites in dogs. However, while it does not kill heartworms, it can be used as part of a treatment plan for heartworm disease.

Ivermectin does not kill adult heartworms and therefore cannot be used as a cure for heartworm disease. If your dog has been diagnosed with microfilaria (baby worms) or circulating antigens (a type of immunologic response to the presence of heartworm larvae), your veterinarian may prescribe ivermectin at the same time as he or she prescribes an additional medication that will eliminate existing larvae and prevent new ones from forming.

Dogs with a mutation of the MDR1 gene may suffer from seizures or die after taking ivermectin.

Dogs with a mutation of the MDR1 gene may suffer from seizures or die after taking ivermectin. The MDR1 gene codes for P-glycoprotein, a protein that helps the body get rid of drugs. P-glycoprotein is found in the liver, intestines and brain.

The mutant form of this gene has been shown to cause sensitivity to ivermectin in some dogs. If your dog is sensitive to ivermectin because of this mutation, it can lead to severe side effects including death if they take high doses of ivermectin over time (more than once per month). The mutations occur randomly and are not inherited from parents or siblings.

Treatment for overdose includes inducing vomiting and administering activated charcoal followed by supportive care to manage symptoms.

If your dog has overdosed on ivermectin and is showing signs of poisoning, you should take the following steps:

  • Induce vomiting at once if possible. A dose of hydrogen peroxide may be given to induce vomiting if needed.
  • Administer activated charcoal as soon as possible after ingestion of ivermectin has occurred, then continue to monitor the patient for at least an hour after administration of activated charcoal because symptoms may occur during this time period. Monitor blood pressure and heart rhythm closely; give intravenous fluids (if indicated) with electrolytes; and administer oxygen if necessary to correct respiratory problems caused by high doses of ivermectin or by other side effects such as seizures or arrhythmias.

Ivermectin kills many different types of parasites, but it’s important to avoid overdosing your dog on this medication.

It’s important to note that Ivermectin is safe when used as directed. However, if your dog receives too much of this drug, it can cause severe side effects.

Ivermectin does not kill heartworms, so make sure your veterinarian checks for these parasites before administering the medication. Also keep in mind that ivermectin does not kill ticks or fleas on its own; if you have an infestation of either pest and want to use ivermectin as part of a treatment plan, you should ask your vet about using another medication in conjunction with it.


Ivermectin is a safe and effective drug to use in dogs when used as recommended by your veterinarian. However, it’s important to always follow the exact directions on the label. It’s also important for your dog to be tested for heartworms before using this medication. If you’re giving ivermectin to prevent heartworm disease, retesting should occur every 12 months (even if your dog has never skipped a dose).