Heartworm prevention

[Diana Vittorio]

My 3 year old labradoodle has had some pretty bad GI issues and this last month was exceptionally bad. I've been to several vets and none know what is wrong with her, just keep putting her on metronidazole and antiemetics. Recently went to a holistic vet who has her on a raw diet and she is doing good right now. But after giving it serious consideration on the timing of things, and doing some research, my best guess is that she is experiencing some adverse reactions to Heartguard Plus. And the more it builds in her system, the worse the symptoms are. Seems she has this lethargy and sort of stumbling gait when we go for our daily. She also has very loud gurgling noises coming from her GI tract, followed by nausea, vomiting bile and loss of appetite. I hadn't made the correlation until recently as the reactions are getting worse. The holistic vet of course doesn't want me to give her any heartworm prevention, she believes by strengthening her immune system through diet, the dog will fight off negative affects of heartworm. I'm a dietitian by trade so of course I believe in treating the immune system nutritionally. At the same time, I live in southern Florida where mosquitos are rampant. I'm scared to give her heartworm prevention, and I'm scared not to. The dog breeder who I admire greatly says to switch her from Heartguard to Sentinel. I'm going to take her back to the conventional vet this week and have her tested for allergies to ivermectin (chemical in Heartguard) and the chemical in Sentinel (milbemycin). She was also on a topical flea treatment called Activyl which I am not going to give her any longer.

There is also a condition called MDR 1 gene mutation (which is not typical in labradoodles) but this defect can cause the dog to not metabolize some drugs properly and they can cross the blood brain barrier and cause neurological reactions similar to the adverse reactions from pesticides. I can have this test run as well while I'm at the vet.

Putting this out there because I could use some insight from anyone who has had similar experience. Thank you.

[Karen, Jasper and Jackdoodle]

I haven't had experience with adverse effects from HW prevents, but my dog has had many of the GI symptoms you've described, and after extensive testing including an endoscopy, he was diagnosed with Inflammatory Bowel Disease, which is an immune-mediated disease similar to Crohn's Disease in humans. With all due respect to the holistic vet, you cannot "strengthen" the immune system through diet, nor does it need to be strengthened. In almost every immune mediated disease, the problem is an immune system that is too strong, in the sense that it is hypervigilant and overreacting to things that a healthy immune system does not. That's why these diseases are treated with immunosuppressants.  I will also tell you that it wasn't until I consulted a veterinary internal medicine specialist that I got an accurate diagnosis and an effective treatment plan. And I also have a holistic vet, who has never once suggested trying to strengthen JD's immune system with diet,especially a raw diet, which is contraindicated and dangerous in dogs with damaged intestinal linings. 
I would also be terrified to not protect my dog against HW, since the treatment is excruciatingly painful and can be deadly. Again with respect to the holistic vet, it is not possible to "fight off" the negative effects of HW, through diet or anything other than effective, proven drug treatment. That doesn't even make sense physiologically. 

[Karen, Jasper and Jackdoodle]

Oh, and with all that metronidazole, have you been using a good probiotic? If not, that could be the problem. The metronidazole destroys all of the good gut flora necessary for proper digestion and stool formation. There have been dogs here who actually developed GI disease from the overuse of metronidazole without probiotic treatment. 

[F, Calla & Luca]

I agree with Karen re: heart worm treatment. I would never rely on diet or the immune system to ward off HW.

[Julie, Eloise & Beasley]

I don't have a similar experience, but I, too, would be scared not to give heartworm preventative especially in southern Florida.  Maybe look at Revolution (selamectin) for her?  No idea if it's chemically different enough from the other two, with regard to the adverse reactions she may be experiencing, but it's an alternative to consider.  I use it on my two with good results.  It's heartworm and flea preventative, but for ticks it only covers the American Dog tick.  Good luck!

[Becka]

I've had Sadie on ProHeart (twice a year injection) for about three years with no adverse effects and no heartworm. I too live in South Florida and would never not have her on HW preventative. Trifexis gave her very bad diarrhea, so she's on NexGuard (monthly chewable) for fleas and ticks, along with the injections.

[Jane, Guinness and Murphy]

When Murphy was diagnosed with IBD, my Vet moved him to Revolution which is topical, so now he's on Frontline Plus and Revolution with no adverse reactions.

[a.k.a. Rodney]

I had a very similar scenario with my doodle who is now 2 1/2 years old when she was in the nine months to 1 1/2 years stage she had similar symptoms and issues as your dog. And was treated in much very much the same way. I really wanted her off the diet dieMetrazol but while she was on it I did put her on a probiotic also She is still on it today! (PROVIABLE DC) The Vet determined that the best route for her would / the best food with not to rich a protein value...as chicken. A dehydrated food product made of rabbit. He also forbade her ingesting any kind of medication besides the probiotic which also obviously included heartworm medication. He then started her on revolution and she's been on that and the dehydrated rabbit ever since she's never had treats because she was trained without them I now can give her occasionally when I use it which is only for the come command a banana chip, which I get from a holistic pet food store
She's a Happy, healthy Doodle now. She wears an 8 mo FLEA collar protection called Seresto. We live in fla for the winter and Il in the summer...bugs both places. She's 11.5 lb GD. Hope this helps inform