This drug was withdrawn from the market when a number of dogs died from it. The company has been trying to get it reapproved ever since. Apparently now they have succeeded, but I wouldn't trust it. With all of the safe, available HW preventatives out there I'd play it safe and give one of the monthly oral or topical heartworm medications. (I give valuheart from MegaPets to my dog. It's a generic version of heartgard that is much cheaper.)

I reread your message and wonder if the ProHeart shot you asked about is one used to treat HW as opposed to prevent it??

There was a ProHeart formulation on the market designed to be given every 6 mos to prevent heartworms, I think it was called proheart6. It was disasterous, and the company keeps trying to get it reapproved.

I'm sorry about your dogs testing positive. You're not the first person I've heard having a dog who was on HW preventative getting HWs despite the protection.

The treatment for heartworm is very hard on dogs, I've heard. I hope yours get through the treatment ok. I'm sorry this happened to them.

(PS I meant to type PetsMegastore above.) Maybe your dogs would do better with a topical preventative like revolution when they are cured. If a dog vomits a HW pill they will be unprotected for a month. Not saying that is why yours caught heartworms, but it's always a possibility.

Proheart has not been tested in dogs with heartworm disease. I would not use it. I would use an ivermectin-based heartworm prevention and retest in 6 months. If still heartworm positive, I would treat with Immiticide.

I have not seen a reaction to proheart yet and have been giving it to some patients for 2 years. I am very careful to follow manufacturers recommendations and not start it in a dog older than 8 years, to not use it in combination with vaccinations, to not use it in dogs with dermatologic disease, to not use it in growing dogs, to not use it in dogs with liver disease etc. I personally prefer ivermectin based heartworm prevention because it seems to do a better job in controlling intestinal parasites in this region.

Thanks everyone..

We took our Winnie in today to be tested and she was positive also.(wasn't surprised) I wasn't able to go with DH today but he thoroughly questioned the vet and his wanting to start Tank on the ProHeart6 shot. He wants use to use the shot as a treatment/preventative measure.
DH shared with him all of my fears..
Dr M said he had no second thoughts with starting Tank on it. That he uses it on his own dogs and wouldn't recommend anything for Tank that he wouldn't do to his own. He said he has never seen any side effects on any of the dogs that use it. He does make the dog stay for 4 hours as a follow up. He told DH that many years ago it was introduced into the market, dogs had problems, they pulled the med and have reintroduced it in the past couple of years.

With Winnie he says she is a little more + than Tank so we are giving her the us Doxycycline and then will start her on a different heart worm preventive(Tri Heart Plus) for 6 months and reevaluate where we are then.

I trust Dr M..he is not out to make money, he truly cares about the pet and the owners feelings. He was so good to us and to Bear when we had to put him to sleep in 09..