The Side Effects of Heartguard for Dogs

There are four different types of Heartgard medication; the most important variation is in the ingredients. The original Heartguard has only one parasite control ingredient, ivermectin, for the prevention of heartworms. The side effects of Heartgard for dogs vary, as the weight and general health of your dog plays a role in what side effects, if any, your dog will experience. In many cases, side effects result from high doses or overdoses of the drug.

  1. Gastrointestinal Problems

    • Dogs that suffer from Heartgard-related side effects might show signs of gastrointestinal problems, which include diarrhea and vomiting. Loss of appetite may result from these problems. In many cases, such side effects will appear within 24 hours of giving your dog the medication. Proper storage of the medication can help prevent these side effects. Remove the wrapper from only the chewable dose you are about to administer, and leave the rest of the medication in the package. Once you give the medicine, close the package and follow the storage instructions provided.

    Loss of Motor Skills

    • Loss of motor skills, symptoms of which include physical trembling, lack of balance and lack of coordination, are more serious side effects of Heartgard. This type of side effect generally stems from an overdose of the medication. If you administer higher doses of Heartgard to your dog than prescribed, the medication can adversely affect your dog in this way.

    Physical Changes

    • In severe cases resulting from an inappropriate administration of the Heartgard chewables, side effects include dilation of the pupils, blindness and irritation, as well as diarrhea and vomiting. It is important to follow the dosage instructions carefully so an overdose does not occur. For example, no matter the size of your dog, give only one chewable a month. Giving more than one can result in an overdose.