Is Horse Heartworm Medicine Good for Dogs?

Larger-quantity or -sized items often cost less to use than smaller ones, including heartworm medications. However, even if using horse heartworm medications for your dog costs less, it may not give good or safe results. A dose of equine heartworm medicine treats a horse weighing as much as 1,500 pounds. Inaccurately dividing it into a dose for your dog creates a risk of providing a lethal dose or serious medical problems, according to Mar Vista Animal Medical Center.

  1. Type

    • Medications used for heartworm prevention in horses generally contain ivermectin. The drug treats and prevents parasites in various mammals, including horses, dogs, cats, swine and humans. For horse heartworm prevention, the medication typically contains ivermectin. Moxidectin, used for other parasites in horses, treats and prevents heartworms in dogs, according to Bayer Health Care. However, drug companies package medications in different strengths, under various names and by species. Sometimes the medications contain drugs that treat more than heartworms; therefore, make sure the ingredients match the canine wormer without additional drugs.

    Form

    • Available horse wormer medications include pastes, granules and liquid-injectable forms. Pastes and liquid-injectable formulas provide the most common means for equine heartworm prevention. Moxidectin typically comes in gel formula for horses. Determining a correct dosage from pastes or gels causes a higher risk than the liquid formula. In addition, flavored pastes need secure storage as your dog may enjoy the taste and receive a toxic dose, advises Sandy Carey, director of public relations at University of Florida College of Veterinary Medicine.

    Dosage

    • Your veterinarian may demonstrate how to determine and measure the dose.

      When used correctly, small doses of heartworm medications typically do not cause serious side effects; however, used in higher doses, either accidentally or for other treatments, they may create problems. The concentrated formula used for large animals, including cattle and horses, makes accurate measurement difficult, according to Mar Vista Animal Medical Center. Ask your veterinarian for the correct dosage for each drug before attempting to treat your dog.

    Drug Interaction

    • Discuss all medications and possible drug interactions with your veterinarian before giving heartworm treatment. Heartworm medications may interact with other drugs and cause serious side effects. Ivermectin used at the normal heartworm prevention dosage usually causes not problems if your dog takes spinosad, a flea control product, according to Mar Vista Animal Hospital. However, the U.S. Food and Drug Administration reports side effects due to dogs receiving higher than normal doses of ivermectin.

    Warnings

    • Before selecting any heartworm medication, consult with your veterinarian about testing your dog for sensitivity to ivermectin products. The most common problem, caused by a genetic mutation, allows some drugs, including ivermectin, to enter the central nervous system, according to Washington State University. The breeds most commonly affected include collies, Shetlands and old English sheepdogs, but other breeds may have the mutation. A DNA test by Washington State University allows you to determine if your dog has the mutation. Dogs sensitive to ivermectin often tolerate accurate heartworm prevention levels of the drug. Attempting to use horse wormer increases the risk of a miscalculated higher dose causing a problem. Test your dog for heartworms before giving it any heartworm medication, warns the American Heartworm Society.