Heartworm Treatment: What Are Your Options?

Kate Barrington
by Kate Barrington
By the time you see the symptoms of this potentially dangerous disease, it’s already too late. Don’t procrastinate – get the 411 on heartworm treatments available for your dog.

Heartworm is a dangerous and deadly disease that is transmitted to dogs and cats by mosquitos. This disease progresses slowly and, unfortunately, most infected animals do not show symptoms of the disease for a full six months after the infection when the disease has progressed to the final stages. Heartworm is easy to prevent by simply having your dog tested annually and by giving him monthly heartworm preventive pills. If you fail to protect your dog and he gets heartworm, your treatment options are few and, depending on the severity of the disease, they may not even be effective.

Related: How Do Dogs Get Heartworm?

Symptoms of Heartworm

As it has already been mentioned, dogs that contract heartworm typically don’t show any clinical signs until the disease has already progressed. Why? Because the moment of infection occurs when a heartworm-carrying mosquito transfers infective larvae into the dog’s blood stream. It takes about 6 months for those larvae to travel through the dog’s blood stream to the heart and lungs where they develop into adults and then begin reproducing. It isn’t until the heartworms begin reproducing that a blood test will pick up the infection – it is also at this point that the dog may begin showing symptoms.

Related: 5 Heartworm Facts You Need To Know

Symptoms of heartworm are related to the clogging of the heart and its major blood vessels. As a result of this clogging, blood flow to other major organs is compromised and those organs may eventually begin to fail. Some of the most common signs of heartworm include a dry cough, difficulty breathing, weakness or listlessness, unexplained weight loss, and loss of exercise tolerance. In very severe cases, the dog’s legs and abdomen may swell from excess fluid and the dog may go into congestive heart failure.

Options for Heartworm Treatment

If your dog tests positive for heartworm there is a certain protocol you should follow. Your first step is to stabilize your dog – this may involve treating some of the symptoms of the disease that have begun to manifest. You should also restrict your dog’s level of exercise because physical exertion will only increase the rate at which the heartworm causes damage to the dog’s already damaged lungs and heart. After your dog has been stabilized your veterinarian will begin treatment. The only approved treatment for heartworm is an arsenic-based drug called Immiticide. Given in two or three injections, this drug will kill the adult heartworms residing in the blood vessels of the heart.

Though Immiticide is the fastest and most effective method of treatment, there is another option. For less severe infections, it may be adequate to treat the dog with a combination of Ivermectin and Doxycycline. This method works more slowly than Immiticide, serving to weaken the heartworm so it cannot reproduce. This treatment method can last for up to 33 weeks, whereas the Immiticide method can work quickly and your dog may test negative for heartworm after six months. Each case of heartworm is different, however, so it will be up to you and your veterinarian to choose the option that is right for your dog.

Kate Barrington
Kate Barrington

Kate Barrington is the loving owner of two cats (Bagel and Munchkin) and a noisy herd of guinea pigs. Having grown up with golden retrievers, Kate has a great deal of experience with dogs but labels herself a lover of all pets. Having received a Bachelor's degree in English, Kate has combined her love for pets and her passion for writing to create her own freelance writing business, specializing in the pet niche.

More by Kate Barrington