Do All Dogs Need Heartworm Pills?

Tricia Christensen
Tricia Christensen

Veterinarians recommend that all dogs not currently infected with heartworms should be given heartworm pills. In the US alone, cases of heartworm are present in every state, and while there are some treatments, these may not help a dog in advanced stages of the disease. Dogs that are first infected may be completely asymptomatic, but as the disease progresses, their suffering can be intense as the heart and the arteries in their lungs become filled with the worms.

Pet owners can save dogs pain, expensive treatments, and possible death by using preventative heartworm pills.
Pet owners can save dogs pain, expensive treatments, and possible death by using preventative heartworm pills.

Prior to putting a dog on heartworm pills, the veterinarian will probably perform a test to be certain that the dog is not already infected. Infection occurs through bites from infected mosquitoes. It is a myth that indoor dogs will not get heartworm, or that dogs with shaggy coats are better protected. All dogs can suffer the occasional bite from a mosquito that carries this larvae.

Heartworms can be transmitted through mosquito bites.
Heartworms can be transmitted through mosquito bites.

Heartworm pills are fairly easy to take, and relatively inexpensive as pet medicine goes. Some topical treatments also can be used in place of pills and may repel fleas and ticks as well.

Veterinarians recommend giving animals heartworm pills to prevent a heartworm infection, which can be expensive and difficult to treat.
Veterinarians recommend giving animals heartworm pills to prevent a heartworm infection, which can be expensive and difficult to treat.

Treatment after a dog is infected can be far more expensive. In the US, there is only one heartworm medication approved by the FDA, and it can have negative side effects on the dog. Additionally, treatment does not always result in a cure, especially when the dog’s heart and lungs are significantly damaged. It may be possible to kill the worms, but the damage may be irreparable.

An ounce of prevention in the case of heartworm pills is certainly worth more than its pound of cure. This medication offers that prevention at a bargain price. Dog owners should talk to a veterinarian regarding whether pills, injections, or topical treatments are the best way to go. Some vets will even work with pet owners on limited incomes to make sure that a dog can be given the appropriate treatment.

Those who think heartworm is not a major illness in dogs, can look at autopsy pictures of the swelled hearts of dogs filled to the brim with heartworms. Progressive symptoms can cause cough, swelling of the heart, accumulation of fluid in the stomach, and swelling in the liver. Dogs can lose their appetite, lose significant weight, and may have fainting spells. Occasionally, heartworms migrate to other parts of the body and have affected the brain, the eyes, and the spinal cord.

It seems unnecessarily to allow a dog to undergo these symptoms when prevention through medication is available at a relatively inexpensive price. Pet owners can save dogs significant pain, potentially expensive treatments, and possible early death by using the preventative treatment. They are something all dog owners should seriously commit to, to prevent needless suffering in pets.

Heartworm disease is a frequent cause of liver damage among dogs.
Heartworm disease is a frequent cause of liver damage among dogs.
Tricia Christensen
Tricia Christensen

Tricia has a Literature degree from Sonoma State University and has been a frequent wiseGEEK contributor for many years. She is especially passionate about reading and writing, although her other interests include medicine, art, film, history, politics, ethics, and religion. Tricia lives in Northern California and is currently working on her first novel.

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Discussion Comments


I am part of a 501(c)(3) rescue and we recommend that you use prevention year round. We follow the instructions give by our vets as we know accident (a stray mosquito) can get your pet late in the warmer months and early in cooler months. Then go all winter letting the HW's grow and multiply. As for the comment of keep your dog healthy (post 19) and it wont have to go to the vet -- seriously? Accidents happen and some dogs just get sick, period. Also on the Ivermectin comment (post 8), using it is fine, as long as your dog doesn't have HW's or isn't Ivermectin sensitive. We had six dogs that had a reaction to Ivermectin and had to be rushed to the emergency vets for treatment. I have used it myself and actually did not know of of the reaction. But, any dog can have an allergic reaction to any medication.


@anon33130, post 18: Someone at the veterinary office was not efficient with you. Maybe you should switch vets, but at the same time, the veterinarian's office was also looking out for the wellness of your pet. They just didn't do it in the right way. Nail trims can be done anywhere, but they were more concerned with the health of your dog. But I wasn't there for the whole conversation. I can only say what I think they meant. It was just done the wrong way.


So many veterinarians prevent a lot of people from taking their pets for much needed visits because of the cost. There are three in my area, none of which I like. You won't believe this. Ohm my blood is beginning to boil just thinking about it. I called one vet office that is close to me yet I haven't had my dog there in over a year. My dog needed his nails cut, and nothing else, right? Ha! I was told over the phone that I could not get that done because it had been over a certain amount of time since my dog had seen the vet so therefore I had to make an appointment first! Oh, oh my!


I found some natural pill delivery treats called Pill Buddy Naturals made by Complete Natural Nutrition. The dogs loved them and the ingredients used are so much healthier than others I have seen.


You only need to give your dog heartworm medication during the warmer months when mosquitoes are present. If you live somewhere that has a snowy winter, you do not need to give heartworms pills during the winter months. Heartworm pills are expensive, but the vets must buy them from a pharmaceutical company, and they are the ones who charge a ridiculous price before the vet even marks up the medication!

If your vet will allow it, you can get a prescription for the HW medication and buy them online. These companies charge less on average as they can afford to purchase in large quantities that most vet practices cannot. Beware of getting the wrong medication, etc. from online companies, though.

It is a prescription medication, because if you give it to an animal who has heartworms with testing, they can die! This is why a blood test is done to confirm that the animal does not already have heartworms. The reason prescriptions exist is to prevent people or animals from having medication that can seriously harm them or kill them.

Treating an animal that has heartworms is very expensive and has approximately a 50-50 chance of survival. Prevention is the best method.


My vet in Japan just charged me US $18 a pill for 6 heartworm pills. The bill for rabies and filarial injections totaled $180. I will source the heart worm pills myself in future.


my vet charges me $26 for a six month supply of Iverhart Plus. Cheaper than what I've seen online. For her yearly visit to get her vaccinations, fecal test, heartworm test, heartworm meds and exam costs me $100. Some vets do charge too much, I'd find another vet if that was the case. My vet is always giving us money saving tips. If you tell him you can't afford something then he makes a way that you can.


Heartworms are transmitted solely through mosquito bites (not every bite), which is why I started wondering about the winter months myself. It seems like unless someone lived somewhere that was very cold all year long, there wouldn't be anywhere that it wouldn't be possible for them to get it, but it does seem unnecessary from what I read to give it to them in the winter -- at least based on what I've read so far.


I live in sicily. The vet for my dogs told me they don't need heartworm pills. is this true? They also told me they don't need rabies shots. So if you think that you can, please give me some advice. So far, the best advice that i have gotten is to go back to brooklyn! thank you and bye


I live in NYC. Every spring I get my dog blood tested for heartworm, then I start her on the medication for four months, then I stop around Oct. I use LuvMyPet, so no visit fee. I see no reason to give it to her when there are no mosquitoes around in the winter time. I also think vets are a scam. Keep your dog healthy and you can avoid the vet.


I give the exact same medication, Ivermectin, to my horses and it is very cheap, about $2 for a tube that covers a 1,200 lb. horse. It is really a gigantic veterinary ripoff when they charge so much for those tiny Ivermectin pills for dogs.

I would just give my dogs the horse medicine, but I am afraid the dosage would be incorrect. Vets are truly taking advantage of pet owners.


while I think it is important to give your dog heartworm prevention medication, by the way, it cost me 140.00 per year for the medication plus the visit to the vet, which is another 65.00.

I do not think it should be a prescription. I can remember long ago when you could get it over the counter. This is nothing more than a money maker for the veterinary and a way for them to rip people off.


It is not a scam to give your dogs heartworm medication. Some dogs won't ever get it, and some will, but it is a horrible thing to have (the last dog I adopted was infected with them, it took so long to get her healthy again). And it does not cost $15 a month plus a visit.

You can get 6-12 months in advance or buy online without a vet appointment.

I just got my dog a refill today online and it cost me $39.99 for a 12 month supply.


Contrary to what this article says, heartworm medicine is in fact very expensive. The vet charges $50 a visit and the pills are about $15 per month. This is close to $300 per year, $600 if you have two dogs. This seems like a scam by the Veterinarian Industry. Veterinarians are worst than dentists in terms of trying to scam their patients.


OK I took my lab puppy to the vet today. I was told in the part of Montana that I live in that it is not neccesssary to give your dog a heartworm pill. Is this really true? I used to live in Indiana and we always had our dog on Heartworm pills? Any help would be greatly appreciated.


Is it right that heartworm pills can be efficient for fleas too? Which brand do you recommend?


I would like to know if you need to give your dog heartworm pills in the dead of winter.


I live in the Northeast. Do I have to give my dog heartworm pills during the winter months?

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