Treatment occurs in several steps. In the first step the animal is given 2 injections of Immiticide® about 2 months apart that will kill adult heartworms. Prior to this, most dogs will be put on 2 weeks of Doxycycline to treat the potential bacteria, Wolbachia, that lives on the surface of the heartworm parasite. This is serious and animals are always hospitalized for this procedure and kept quiet. As the parasite dissolves it is possible for the pieces of the worm to act as emboli and cause pulmonary and or heart failure. It is absolutely crucial that the animal not be exercised or walked or excited for weeks after Immiticide® treatment. One month later the dog is treated to rid the body of circulating microfilaria. This is done by oral administration of ivermectins.
Some dogs may not be treated because of severe organ failure. Instead of treating those animals, the organ illness is addressed. Dogs that are treated may have clinical heart and or lung disease. Those conditions need to be addressed.
Economically, the treatment regimen is expensive. In South Florida, complete treatment is about $1500. Another good reason to have pet insurance! Some people can not afford the cost of heartworm treatment. Doing nothing will just allow that animal to serve as a source of infection. In those cases ivermectin administration, once a month, will at least clear the microfilaria so the animal is not infective to mosquitoes.