Ivermectin Side Effects in Dogs

Ivermectin is a commonly prescribed medication that is often used to treat parasites in dogs. Ivermectin has also been used to treat ear mites and as a heartworm preventative in dogs. This medication is only available by a prescription from a veterinarian. While generally safe, it does have a risk of side effects, especially in high doses.

  1. Allergic Reaction

    • Ivermectin should not be used in dogs that have a known sensitivity to the drug. Ivermectin can cause an allergic reaction in some dogs, which is a life-threatening medical emergency. The symptoms associated with an allergic reaction are wheezing, difficulty breathing, swelling of the lips, swelling of the eyes and swelling of the tongue.

    Toxicity

    • Ivermectin toxicity may occur in some dogs, especially at high doses or when used in combination with the medication spinosad. Certain breeds may be at an increased risk of Ivermectin toxicity. These may include Old English sheepdogs, Shetland sheepdogs and Australian shepherds. Other conditions that may put dogs at an increased risk of toxicity are being very young, central nervous system diseases or a history of head trauma. The symptoms of Ivermectin toxicity are depression, excessive drooling, dilated pupils, vomiting, weakness, tremors, being disoriented, blindness, being nonresponsive, the inability to get up, lack of appetite, slow heart rate, stupor, seizures and a slow respiratory rate. Ivermectin toxicity is a serious condition that may also cause coma and even death. While there are no known medications that can reverse the effects of Ivermectin toxicity, if discovered in time, veterinarians may treat the condition by inducing vomiting, performing gastric lavage and administering activated charcoal to minimize the dog's absorption of the drug.

    General Side Effects

    • Ivermectin may cause adverse effects in dogs. Some side effects to consider while your dog is taking this medication are fast heart rate, flushing, dizziness, fever, joint pain, muscle pain, rashes, diarrhea and eye irritation. Ivermectin may also interact with other medications such as tranquilizers and sedatives and should not be used with these medications. Flea control products such as collars and dips containing the ingredient amitraz may also increase the side effects associated with Ivermectin. Therefore, the two should not be combined.