what are the signs of heartworms in dogs?
Pet Health Questions and Answers

Treating Heartworm in Dogs

In the past, treatment for heartworm was incredibly risky and painful for a dog. Luckily, we have new medications on the market that have led to recovery in 95% of cases!

Your veterinarian can treat your dog’s heartworm with Immiticide vaccinations combined with other medications to keep them comfortable and completely flush the parasites from their system. Your dog will need up to a month of complete rest after treatment to recover.

Luckily, there are also heartworm prevention medications on the market that will stop your dog from catching heartworm altogether.

In this article, we’ll talk about preventing and treating heartworm, along with how to care for a dog after heartworm treatment. 

Table of Contents:

What is Heartworm, and How Does a Dog Catch it?

Heartworm is a disease caused by microfilariae, which are transferred by mosquitos. Your dog can only catch heartworm through a mosquito bite—not from contact with other animals.

It’s also important to note that not all mosquitos carry the larvae that cause heartworm. In areas with high mosquito populations, it’s more likely for your dog to become infected through mosquito bites.

The larvae aren’t life-threatening unless they mature. Often, a dog’s body can fight off small numbers of larvae before this happens.

Adult parasites grow up to a foot long and wrap themselves around your dog’s heart and other organs, eventually leading to organ failure and death if left untreated. 

Keep reading to learn how to treat and prevent heartworm.

heartworm preserved in a jar

How Long Can a Dog Live with Heartworm?

This depends on the severity of the condition. A mild case can be dealt with almost naturally by allowing the existing worms to reach the end of their lifespan and prevent any more from infesting your dog, but this isn’t advisable.

The parasites are likely to reproduce, making your dog’s prognosis even worse. It’s also likely that, by the time you’ve noticed your dog has heartworm, the case is fairly severe.

Overall, every case of heartworm is different, and there is no definitive answer as to how long an untreated dog will survive without medical intervention. One thing is known, however – ignoring heartworm will place your dog in a great deal of avoidable pain and discomfort.

The good news is that, when treated, heartworm rarely results in death. 95% of dogs with heartworm can recover and go on to live full lives.

How Can Heartworm Be Prevented?

Preventing heartworm is a much better approach than waiting for it to strike and then attempting to eradicate the problem. Avoiding any contact with mosquitos is easier said than done, especially if you live in a warm or subtropical climate, but thankfully, there are many ways that any dog owner can minimize the risk of infection.

These include:

1) Vaccinations

ProHeart 6 (aka Moxidectin) is approved by the FDA, and thus will be available from almost any vet. Be aware that a vet must administer the shot, though – this is not an OTC treatment – and it will not be available to puppies or dogs over seven years old.

A ProHeart 6 shot will protect a dog for six months, but it won’t prevent other infestations such as roundworms, hookworms, and whipworms. Ensure that your dog doesn’t suffer a reaction to the shot either, as some canines react poorly to the treatment.

2) Oral Pills

Arguably the cheapest and easiest solution for preventing heartworm from taking hold in your pet is to use oral pills, which will kill any larvae before they have the chance to grow and develop into adult parasites.

Oral pills won’t last as long as a shot, but this may be fine for a climate where mosquitos are not present for particular seasons.

Speak to your vet if you’re not sure which particular treatment is best for your dog. Some commonly-used medications include Heartgard and Ivermectin, both of which are readily available.

3) Topical Solutions

Lastly, your veterinarian can prescribe topical solutions like Revolution. This medication is applied to the back of your dog’s neck and works to prevent heartworm, fleas, ear mites, mange, and certain ticks.

This can be more difficult to administer than pills, especially for long-haired dogs. Ask your veterinarian if they recommend topical solutions for your situation—some will advise against it depending on the dog. 

4) Regular Testing

Take your dog to the vet at least once per year for a full check-up, including testing for heartworm. This is just a simple blood test, and it could save a lot of expense and heartache further down the line if it identifies the disease at a very early stage, before symptoms have started to manifest.

Not Recommended

We don’t recommend mosquito repellents as these products are typically toxic to dogs. The options the CDC lists for human use include DEET, Picaridin, and lemon eucalyptus oil, all of which can make your dog sick.

Mosquito repellents might not repel all mosquitos either, making them less effective than the solutions listed above.

Holistic treatment is also not recommended for heartworm prevention. There is, unfortunately, no proven all-natural, homemade solution to heartworm.

Therefore, we recommend following your veterinarian’s plan which should include a medically-proven medication. 

vet checking for signs of heartworm in a dog

How to Treat Heartworm in Dogs

If the results are in and you’re led to believe that your dog has heartworm, there are many steps that will need to be taken to treat the condition.

These are as follows:

  • Get a Second Opinion. If your dog does have heartworm, you’re staring down the barrel of a lengthy recovery period with a hefty bill waiting for you at the end of it. See a second vet if necessary, and make sure beyond all doubt that the diagnosis is correct.
  • Don’t Allow Fido to Exercise Too Much. If your dog has heartworm, any physical exercise will only aggravate the problem, and potentially lead to them collapsing. How much exercise your dog will be able to enjoy will depend on how far along the heartworm is within their body.
  • Prevent the Problem from Getting Worse. This ties in with the step above – many vets will not begin the process of treating heartworm until they are quite confident that it will not progress any further. This means that you’ll have to keep your dog calm, and possibly undergo many initial treatments before the real work begins.

Once this has been completed your vet will start the process of treating your dog’s heartworm.

Medical Treatment for Heartworm in Dogs

The most popular medical treatment for heartworm is called Immiticide. Though it’s an improvement from formerly-used treatments, it’s still not a fun experience for the dog or their owner.

Immiticide, which contains traces of arsenic, is injected straight into your dog’s body – usually in two separate treatments within a 24-hour period for an intensive treatment, or three over the course of a month. After a month, if the treatment is deemed successful, there will be a course of Ivermectin to kill off any larvae that remain.

The good news is that this will kill the adult worms that are infecting your dog almost straight away – it is arsenic, after all. The bad news is that, in doing so, these worms start to decay and find their way into your dog’s bloodstream and lungs. 

Coughing is a common side-effect, but you should see your veterinarian if your dog’s coughing is excessive or they cough up blood.

Dogs treated with Immiticide recover in 95% of cases.

Once a treatment course has been successfully completed, your dog will be expected to attend regular check-ups to ensure that the problem has not returned.

Is Treating Heartworm Painful?

Yes. Not only does the injection involve an arsenic compound, which will always cause a reaction, but it also has to be administered to the canine’s lower back. That means that your dog will be left in a great deal of pain in the short-term and may struggle to use their back legs for a few days afterward.

Often, an anti-inflammatory or pain medication is prescribed to lessen your dog’s pain from the injection.

what are the side effects of heartworm treatment?

What are the Side Effects of Heartworm Treatment?

As we have just covered, there is always a risk of a dog coughing up blood after a dose of heartworm treatment, they may have blot clots inside their body, and their lower back and hind legs might ache from the vaccination.

Your dog will require regular supervision from a vet throughout their recovery process, so be sure to discuss any possible side effects at their first warning sign. The side effects of heartworm treatment typically peak after a week or two, so it’s particularly important that you’re vigilant about watching Fido during this period. 

If your canine companion is vomiting, gagging, or coughing heavily, get them some medical attention ASAP. This will be a result of the dead worms reluctantly leaving their system, and veterinary help may be required.

If a dog has been provided with the correct dosage of medication to prevent heartworm, there should not be any side effects, especially if you have checked with a vet to ensure that there are no allergies to contend with.

However, some dogs may experience the following after taking heartworm preventative:

If your dog exhibits any of these symptoms after taking a preventative medication, speak to a professional for advice on switching them onto something else.

How Much Does Heartworm Treatment Cost?

This depends on just how much treatment is needed – which, again, depends on how far the disease has progressed within your dog.

It is safe to say that anybody looking to undertake a full course of heartworm treatment for their dog should be prepared to hand over at least four figures. We did warn you that heartworm treatment doesn’t come cheap. 

This cost will cover the medications required to treat your pet, and the fact that they will need to spend at least one night at the vet – or possibly longer if surgery is needed.

There will also be a period of convalescence after the fact, possibly one that involves the purchasing of medications that will help your canine chum overcome any side effects of their treatment. That’s a lot of money and a lot of discomfort for your dog. Surely the idea of prevention is much more appealing?

Will My Pet Insurance Cover the Cost of Heartworm Treatment?

This depends on your contract with your insurer, so read the small print very carefully before deciding upon which policy to take out.

Some policies will cover the cost of preventative measures against heartworm, others will pay for the surgical or medical intervention required after the fact, and others still will play no part at all in heartworm.

Where pet insurance is concerned, you always get what you pay for. Pay close attention to what is offered by your insurer (and consider the price of the excess alongside your monthly payments), and make an informed choice if you consider your dog to be at risk of contracting this condition.

dog taking heartworm medication

How to Care for a Dog After Heartworm Treatment

The most important thing to know is that your dog will to be watched regularly, so keep in constant contact with your vet during the recovery period and be prepared to leap into action if you spot any untoward symptoms as part of your canine’s recovery.

It’s also important to know that, after a dog has undergone heartworm treatment, they’ll have to take things very, very easy. This means that you’ll have to make your dog comfortable and give them space.

If you haven’t previously done so, check out the guide on to how to crate train a dog that barks and whines. The same advice applies here – giving your dog somewhere they feel safe and relaxed is hugely important.

Your dog will also need to rest, so make sure that their crate (or open bed if that’s the approach that you decide to take) is somewhere away from the rest of your family. If your dog is under the weather, young children may want to cheer them up by playing.

Unfortunately, Fido will not be able to undertake exercise while recovering from heartworm treatment, so remove the temptation from his or her path. Plenty of love, plenty of food and water, and plenty of sleep – that’s the only way that your dog will make a full recovery.

How Long Will It Take for a Dog to Be Active Following Treatment?

It will take around six weeks – four at the absolute least – before your dog can get back to being their old running, jumping and playing selves.

It’s hugely important that your canine companion is given enough time to recover fully from their ordeal, as excessive exercise will aggravate their problems and potentially undo all the work of their invasive and expensive treatments.