Why would Heart Worm medication kill my dog if...?

Question

If I were to put my dog on Heartguard and she has heart worms why would the medication kill my dog?

Answer 1

Adult heartworms live in the upper right chamber of the heart, and cause trouble by clogging up the area and obstructing blood flow. Baby heartworms, microfilariae, float around in the bloodstream. The babies are harmless until a mosquito ingests them along with the blood. the babies grow to teenagers inside the mospuito and when the mosquito bites to feed again, the teenage microfilariae are released into the dog and eventually move up into the heart as adults.

Heartworm preventative medication is given to prevent a mosquito bite-induced infection of teenage worms from becoming adults and obstructing bloodflow. If a dog, however, has already been bitten, the adult worms lay eggs which hatch into babies and the dog's bloodstream is FULL of microfilariae.

Now you apply the preventative which kills all these microfilariae suddenly... what you end up with is a MASSIVE number of baby worms dying and breaking up and causing clotting in multipule arteries and veins, as well as causing a toxic shock to the dog when they break open. This kills the dog... within about 20 to 30 minutes of giving him the medication.

This is why the makers of heartworm preventitives, such as HeartGuard, place warning lables on their products, and why it is essensial to keep up with the prevention treatment every month (or as directed). A dog who tests positive for heartworms must see a veterinarian for a special kind of treatment which is aimed at killing the adults first(cause they're still making more babies) and then slowly killing off the babies in the blood. This treatment takes a couple of months and includes restricted exercise and forced cage rest.

It is much cheaper and much more enjoyable for the dog to just take the preventitive. Cats can also get this disease and there is no cure for them! Please put your cats on prevention as well as your dogs.

-RVT
(Registered Veterinary Technician)

Answer 2

The medication itself won't kill your dog. It will kill the heart worms and the resulting complication from having a bunch of dead worms in your dog's heart would kill your dog. Heart worms have to be killed off gradually so that the body can get rid of them safely. If you give your dog heartguard and your dog already has heartworms then the medication would kill ALL of the worms all at once. then this big clot of dead worms would then be thrown out into the blood stream. This clot could quickly travel to the brain or lungs and block off the blood flow which can lead to stroke or just plain death. Just the same way that if a person has a blood clot in their leg and it gets loose it can kill them quite quickly and unexpectedly.

Answer 3

Because if your pet does have heartworms and you put it on a preventive it could kill off too many of the worms at once and cause a clot in the capilarie or the decaying dead worms can cause massive infections.
No vet will sell you heartworm preventive without testing for a infection of the worms first. Plus heartworms weaken the dogs heart and your pet could already be damaged. An ounce of prevention is worth a pound of cure.
The main ingredent of most HW meds is Ivermectin and that will kill adult as well as larva worms. Do as your vet recomends and keep your pet in the meds for life. Better safe then sorry. The pills are really cheap compaired to trying to remove a massive infection of heartworms.

Answer 4

If your dog was heavily infected with heartworms and you gave her heartworm medication it could kill her because it would cause the adult worms to die off too quickly thus blocking bloodflow in veins & arteries.
This is why it is important to get a heartworm test done before giving heartworm meds and why heartworm medications are by prescription only. It is also why if heartworms are present it is important to follow the vets treatment to the letter.

In some cases heartworm medication can be used as treatment but only on advice of a vet and under strict control.

Answer 5

Heartguard will not kill your dog. I am in a rescue and we, under vet supervision, have had a heartworm dog on Heartguard until we could raise the funds to treat him.
Go to http://www.evidencebasedvet.com
Click on articles and scroll down to the article on heartworm.
Dr. Malernee links you to the government's website to show you that it is safe to give Heartguard to a positive dog. They were tested by the makers on heartworm positive dogs !

Answer 6

Heartguard is a PREVENTITIVE. If u suspect that ur dog has heartworm, the vet can run tests and then either give u the treatment for the worm or the preventitive.

Answer 7

Honestly, I don't have my dogs on it. I think it depends on your area and where you live. I live in Southern CA and "supposedly" heart worm disease isn't very prevalent in my area. It is a good idea to keep your dog on it, just in case. But like my vet said, you don't have to. But keep in mind paying the money you do for the heart worm meds is way worth it in the long run, because if you pet does get heart worm it is a ton of money to try and cure your pet along with some pricy bills ALSO your pet will go through a lot of stress on their body. I suggest asking your vet and letting him give you some suggestions.

Answer 8

heartguard is a preventative NOT A CURE.. different drugs for different purposes.