Ivermectin for Dogs

Usages, Safety and Side Effects of Ivermectin in Dogs

Jul 17, 2009

Ivermectin is a medication which is used in dogs to treat a variety of different medical conditions in addition to being a commonly prescribed heartworm preventive.

Ivermectin is available in many different formulations and is found as one of the main active ingredients in many medications, including Heartgard®, Ivomec® and Acarexx®

Usages of Ivermectin in Dogs

Ivermectin as a Heartworm Preventive Medication in Dogs

Ivermectin is approved by the United States Food and Drug Administration (FDA) to prevent heartworm infections in dogs. Products containing Ivermectin are normally administered monthly for heartworm prevention and include medications such as Heartgard®, Iverhart®, Tri-Heart® and many other generic ivermectin-based heartworm preventive medications.

When used as a heartworm preventive medicine, ivermectin is used at much lower dosages than when used for other purposes. When used at the lower heartworm prevention dosages, ivermectin has a much lower potential for side effects than when used at higher dosages and this is the reason that ivermectin is approved for use as a heartworm preventive medication but must be used off-label (in a fashion not approved by the FDA) for many other purposes.

Ivermectin for Treating Ear Mites in Dogs

Ivermectin is also available as a topical ear medication known as Acarexx®, which is approved for use by the FDA in treating ear mites in dogs and cats.

Off-Label Usages of Ivermectin in Dogs

Ivermectin is used in higher dosages to treat both demodectic and sarcoptic mange in dogs. Ivermectin used in these dosages is considered to be an off-label use of ivermectin as the drug is not approved by the FDA when used at these dosages. Off-label usage is common and ivermectin is frequently used by veterinarians to treat mange in dogs but dog owners should be aware that the dosages are much different than those dosages used for monthly heartworm prevention.

Side Effects Associated with Ivermectin in Dogs

While ivermectin is considered to be a reasonably safe drug, even at dosages used for treatment of mange in dogs, side effects can occur. In addition, some dogs may harbor a genetic predisposition to ivermectin sensitivity which places them at further risk, especially when ivermectin is used at higher dosages.

Ivermectin should not be used in high dosages with valium or tranquilizers related to valium, amitraz dips, collars or topical treatments, or Comfortis® due to the potential of adverse drug interactions.

Dogs with a Genetic Sensitivity to Ivermectin

Breeds which may possess a genetic sensitivity to ivermectin are Collies, Shetland Sheepdogs and Old English Sheepdogs, although genetic sensitivities have been seen in individuals outside of these breeds as well. A blood test which detects the genetic mutation responsible for the ivermectin sensitivity is available and may be advisable for high-risk dogs before administration of high dosages of ivermectin. Heartworm preventive dosages of ivermectin are normally low enough to be safe for these high-risk dogs.

Symptoms such as uncoordination and dilated pupils are of particular concern and can lead to death if treatment is not sought immediately.

Use of Ivermectin Products Approved for Large Animals in Dogs

There are several products containing ivermectin which are approved for use in large animals, such as cattle and horses. Ivomec® is one example. These products contain ivermectin in much higher concentrations than those normally found in small animal products. Though it is theoretically possible to dose Ivomec® (and other large animal ivermectin products) in a concentration appropriate for small animals, even small mistakes in the measurement of these products can lead to toxic doses of ivermectin being administered to the dog being dosed and, for this reason, the use of these ivermectin products is not recommended for treating dogs.

Ivermectin is a commonly used medication with many different applications. Though a reasonably safe medication in most instances, some individual dogs may be at higher risk of possessing a genetic sensitivity to ivermectin and ivermectin should be used with extreme caution in these individuals, particularly when used at higher dosages.

The copyright of the article Ivermectin for Dogs in Pet Products is owned by Lorie Huston. Permission to republish Ivermectin for Dogs in print or online must be granted by the author in writing.