I have a four year old great dane who I just found out has heart worms! I was wondering what would be the best treatment for her. I was going to try an herbal treatment simply b/c I’m afraid of leaving her for two days. She is deaf and partly blind in one eye and has a serious case of separation anxiety. But I feel that two days isn’t going to care her for life. Any help would be greatly appreciated.

Kristin
Mobile, AL

When it comes to heartworm disease, a microgram (or, for many Great Danes, 23 micrograms) of prevention is worth a freight train load of cure.

Heartworms live in the heart and the arteries leading out of the heart. They cause significant damage to these structures when they are alive. When they die, regardless of the cause of death, they pass into the lungs and they can block blood flow through these very important structures.

Heartworms can be killed with an arsenic-containing product called melarsamine. Melarsamine has a relatively low margin of safety and it often leads to severe pain at the injection site. Melarsamine recently has become increasingly difficult to obtain; some vets can’t get ahold of it at all.

Another heartworm treatment involves the use of an antibiotic called doxycycline to kill a microorganism upon which heartworms may be dependent for survival. Doxycycline treatment is still essentially experimental.

Some universities are exploring the option of using special catheters to remove the worms from the heart by way of the jugular vein. This treatment option is promising but it is in its infancy and it’s not available to most dogs.

Serious complications from heartworm treatment are not uncommon. Most of the serious reactions are the result of dying worms blocking blood flow to the lungs, rather than direct toxicity from melarsamine or any product.

In order to reduce the risk of these serious complications, serious heartworm infections are treated with the goal of a “graded kill”. This means that the goal is to kill the worms slowly and gradually rather than all at once. Most lungs can handle a dead worm or two at a time; a dozen dead worms could lead to catastrophe. Dogs sometimes are hospitalized for heartworm treatment so that graded treatments can be performed on consecutive days. Hospitalization allows monitoring of the dog; it also ensures that the dog will not engage in any activity during treatment–activity can exacerbate the risk of complications when dead worms block blood flow through the lungs.

Unfortunately, although currently available treatments for heartworm are extremely far from perfect, they are better (in most cases) than leaving the worms in place. Sadly, that is what appears to be what happens with the herbal remedies that are sometimes touted for the disease. From what I can tell, the herbal remedies work by allowing the heartworms to die of old age. In other words, they do nothing.

I am not opposed to the concept of herbal remedies. If there were one that worked for heartworm disease I’d be all over it. However, I am opposed to any treatment that is not effective or that could put my patients at risk.

I don’t like melarsamine but for most heartworm-infested dogs melarsamine treatment, if available, is the best option.

For all other dogs (and for cats living in high risk areas), regular heartworm prevention is the best bet by far. My pal Buster gets his on the first of every month.

Photo: heartworm disease is spread by mosquitoes.