HeartGard for Dogs

GENERAL

Heartgard for Dogs is manufactured by Merial. Merial is a large company that was first founded in 1997, as a joint venture between Sanofi Aventis and Merck & Co. Merial specializes mostly in products for the health needs of poultry, pets and many other animals. Currently, Merial is present in over 150 countries, and employs 5,400 people worldwide. Aside from producing Heartgard for Dogs, Merial also produces Heartgard for Cats, Frontline, Previcox and Frontline. In 2007, Merial was investigated for a strain of foot-and-mouth disease  that appeared in the United Kingdom. The outbreak was eventually traced to the drainage system of one of Merial’s factories that produces a vaccine.

PRODUCT FORMULA

Heartgard for Dogs is available either as a real-beef chewable tablet, or as an unflavored tablet for dogs with beef allergies. The tablet is given once per month, and is stated as being able to prevent heartworm for the full month in between doses. One of the benefits of using Heartgard include the fact that it is palatable, with most dogs ingesting the medication voluntarily. In addition to protecting against heartworm, Heartgard also protects against roundworms and hookworms.

ACTIVE INGREDIENT

The active ingredient in Heartgard is ivermectin, a broad-spectrum antiparasitic medication. Ivermectin works by binding to glutamate-gated chloride channels. These channels are specific to certain invertabrates. Though ivermectin does not usually cross the blood-brain barrier in mammals, it still may result in serious side effects if given in excessive doses. Symptoms of ivermectin toxicity include depression, weakness, vomiting, chewing fits, difficult breathing and seizures. In severe cases, symptoms such as increased heart rate, pulmonary edema, shock, muscle tremors, coma and death may result. The symptoms of ivermectin toxicity in cats are different from the symptoms seen in dogs.

CUSTOMER REVIEWS

Heartgard is one of the most popular heartworm medications used by dog owners, and is subject to mostly positive reviews. Most dog owners state that the real-beef taste of Heartgard is an extremely positive feature of this product, especially for dogs that have trouble taking pill-based medications. As far as effectiveness, most customers also have positive things to say. The monthly dose seems to be sufficient to protect most dogs against heartworm.

The few negative reviews stated that a very small percentage of dogs experienced neurological symptoms in reaction to the ivermectin in Heartgard. However, this seems to be very rare, with around 96% of customers reporting being able to use Heartgard without any problems.