Risks of using heartworm prevention on a heartworm positive dog?

Question

Does anyone know the side effects of using heartworm prevention (such as Revolution or HeartGuard) on a heartworm positive dog? I know they can have mild or severe reactions, but can someone give me examples of which kinds of mild or severe reactions could occur?

Thanks!

P.S. I am just curious, my dog does not have heartworm.

Answer 1

I don't know what the side effects would be, but I would not do it because I would not want the dog to have ANY side effects or cause any side effects that I may cause. I'd feel guilty. The dog needs to get rid of the heartworms first and then be given the heartworm prevention.

Answer 2

My father-in-law has a lab that has heart worms even though he was on the med heart guard. He still orders the meds from canada and give it to the dog, I have always heard that's a no no but the dog has had no side affect, but I really think he is wasting his money, the meds are to prevent the heart worms not cure it, but I thank it makes my father-in-law feel better. Ed was diagonozes with heart worms approximately 4 years ago and he is fine.

Answer 3

the dog must have the heartworms surgically removed before it can be given prevention medicine, don't give the dog medicine if it has heartworms, as the medicine is for prevention, not removal.

Answer 4

The worry is that if the prev. kills any active heartworm- it could break off, leave the heart and travel to the lungs, causing a PE.