Are there risks associated with the treatment for each stage of heartworm?

That's a tricky question to answer. I guess you could look at it in three ways. So number one, heartworm prevention is extremely imperative. I recommend it to everybody. Very seldom do I see complications with just preventatives. And that kills the infective stage of the heartworm that the mosquito tries to give the dog. So the risk isn’t zero but it’s close. If an animal's positive for heartworms, that means they have adult worms there. And if we go through with that treatment, there's risk associated with that because you are killing these worms that live, again, in the right side of the heart. And as mentioned, they're pretty long (six to eight inches) so killing them is half the battle, but they're still there. So now the body and immune system have to break down that dead worm and dispose of it, for lack of a better word. Well, what happens if they don't do it properly? What happens when that dog's too active after treatment? Then that dead or dying worm, or even partly disintegrated worm, can still migrate and go to the lungs and cause problems there. And the drug itself, while I seldom see reactions or problems to it, it's a pretty harsh chemical. It's got to kill a bunch of big, active heartworms. Any time you put a chemical in the body of a living creature, things can happen that you don't want to happen or don't expect to happen. Do I see it commonly? No, I do not. But they can have pain at the injection site, soreness, and I’ve seen some dogs that are wobbly on their backend. The third and final portion of this long answer is that sometimes when dogs have adult heartworms, those adults will reproduce and cause microfilaria, or baby heartworms. That takes a different modality to treat it. Some preventatives treat that nowadays, but oftentimes we'll use a high dose of ivermectin or something to kill that. Can you have side effects from that? Yeah. It's a high dose of ivermectin. Ivermectin is commonly used as a dewormer or heartworm preventative, but not usually at these levels. You can have dogs that might have a sensitivity to ivermectin, which can cause neurologic signs. You wouldn't want to give that to a Collie breed type of dogs, so Border Collies, Collies, Australian Shepherds, or any of those kinds of herding breeds. You’ve got to be careful when giving high doses of ivermectin. So all these complications are very rare, but they can happen.

There are, but I think, the risks of some injection site soreness or having to do some exercise restriction or things like that with your dog are far better than treating your pet for the disease unless they have many other underlying conditions. But for the most part, I think it's much better to prevent than treat your pet for the disease.

Yes, there are risks associated. However, they are minimal compared to the disease itself. Risks include vomiting and diarrhea, lethargy, which just means very tired, and also soreness at the injection site. On very rare occasions, they can have an allergic reaction to the injection.

There is a slight risk associated with treating heartworms, especially in dogs that are heartworm positive and at a more advanced stage of the disease, closer to heart failure. In these cases, precautions are taken during treatment. For dogs that have just been treated or are on heartworm prevention, most preventatives do not have many side effects.

Yes, there are risks. The greater the stage, the more risk that you take when you're doing heartworm treatment. So you want to catch it as early as you can.