A Guide to Heartworm Medicine for Dogs

Heartworm infections in dogs are very serious and can be fatal if not treated correctly. The treatment often involves heartworm medicine for dogs taken on a yearly, seasonal or monthly basis, depending on the severity of the infection and drugs used.

Causes of Heartworms

Heartworms are caused by parasites carried in mosquitoes. When a mosquito infected with these parasites bites your dog, the larvae eggs are laid into the bite. Your dog can present no symptoms, or become very sick with heartworm infection in a matter of days. An infection is discovered through blood tests and chest x-rays performed on the dog.

Classes of Heartworms

Heartworm infection is categorized in three classes. A Class 1 infection is asymptomatic. A Class 2 infection presents with moderate symptoms. A Class 3 heartworm infection would have severe symptoms. These symptoms include fatigue, loss of energy, increased sleeping, labored breathing, respiratory strains such as sneezing, coughing or hacking, jaundice, convulsions, and emaciation or muscle wasting. If a dog has jaundice, is experiencing convulsions or emaciation, the infection is very advanced, and a vet should be consulted immediately.

Heartworm Treatment and Prevention

Heartworm infection is serious and very difficult to treat. The medications prescribed for this type of infection are regulated, and only a licensed veterinarian can administer these drugs. Immiticide, an arsenic-based compound is one such drug. Other drugs used to treat heartworm include Caparsolate, Ivermectin and Doxycycline. Some drugs are given in two injections, 24 hours apart, while others are administered 2 to 3 months prior to using a main treatment such as Immiticide. Treatment is not without risk. As the adult heartworms die off, emboli can form in the lungs and can cause permanent damage. Dogs are crated up to 6 weeks to limit strenuous exercise, which can exacerbate the problem. In addition, some dogs cannot tolerate the arsenic in Immiticide and need to be treated with alternative therapies, which can slow down the recovery process.

Heartworm medicine for dogs may slow down or eradicate the heartworm, but treatment can be a very slow and tedious process. Some vets recommend medications such as Heartgard Plus or Sentinel year-round or on a seasonal basis as preventative protection. Even after a rigorous regimen of medication, crating and spraying to rid your home of mosquitoes, your dog may still test positive for a heartworm infection. After positive test results come back, another round of treatment, which may then include a combination of drugs, is repeated to eradicate the infection.