Heartworm Treatment: A Step By Step Guide on Getting Your Dog Healthy and Happy

By Chelsea Hunt-Rivera / April 30, 2018
heartworm treatment

If you think your dog may have heartworms or if your dog has just been diagnosed and you’re looking for guidance, you came to the right place! Heartworms in dogs, while scary, is treatable. Keep reading to learn more about the heartworm treatment!

What are Heartworms in Dogs?

If your veterinarian tells you that your dog has heartworms, they are referring to the organism Dirofilaria immitis. Dirofilaria is a nematode (roundworm) that can live up to five years in an infected dog’s heart.

Adult female heartworms can grow up to 14″ long and 1/8″ wide. The male heartworm is generally half the size of the female. During the female’s lifespan, she is able to produce millions of offspring known as microfilariae.heartworms in dogs

As a result, an infected dog may have up to 300 heartworms by the time a diagnosis occurs. Heartworms are found in the heart and nearby large blood vessels of infected mammals.

Unfortunately, your beloved dog is also very much at risk of contracting the parasitic infestation.

Heartworm Disease

If your dog has heartworms, they will need immediate treatment for heartworm disease.

Many veterinarians refer to heartworm disease, or dirofilariasis, as a silent killer among dogs. As you can imagine, the footlong heartworms living in the dog’s heart, lungs, and blood vessels cause severe health issues including heart failure, lung disease, and fatal organ damage.

Veterinarians may refer to heartworm disease as a silent killer because symptoms may not appear until the worm reaches maturity. Even the most doting pet owner may unintentionally overlook the present symptoms, and by the time they take their dog for a vet visit, it’s too late.

Knowing as much as you possibly can about the disease, treatment options, and perhaps most importantly, how to prevent it from occurring in the first place will be crucial for ensuring your dog lives their best life possible.

How Do Dogs Get Heartworms?

how do dogs get heartworms

The one and only way that dogs contract heartworm is through the bite of an infected mosquito. Additionally, there is no way to tell whether a mosquito is infected thus adding to the reasons why prevention of the disease is so important.

Furthermore, heartworm disease exists in all 50 states. While many pet owners may be under the impression that they live in an area where heartworm disease isn’t present, that is simply not true.

Areas like Oregon, Arizona, and California (among others) have all had cases of heartworm disease despite their climates suggesting otherwise.

Can Heartworms Be Passed From Dog to Dog?

No. The only way that a dog can contract a heartworm is through mosquito bites from an infected mosquito. Dogs cannot pass the disease onto another dog. If one of your dog tests positive for heartworms, you should absolutely have your other animals tested, as clearly an infected mosquito was present. However, you do not need to worry whether one dog can pass the disease onto the next dog. This simply isn’t possible.

Heartworm Symptoms in Dogs

As we previously touched on, one of the scariest parts of heartworm disease and why it is so often overlooked is due to the fact that symptoms may not develop until the worms have reached maturity. This can be up to six months after your dog has been bitten by an infected mosquito. By this time, your dog may already be pretty sick.

For this reason, if the dog is showing any of the following symptoms, pet owners need to be hyper-aware that heartworm disease may be at the root of it and seek medical attention right away. The sooner the worms are eliminated, the less devastating the effects on your dog will be.

A dry, soft cough that may lead to fainting

When the parasitic infestation occurs, the worms multiply in the lungs and adjacent veins. A dry, soft cough may be most noticeable after exercising. Even the smallest amount of physical activity may lead to coughing or often, fainting.

Lethargy or inactivity

Dogs with heartworms find it incredibly difficult to be active. Even the most energetic dog will become lethargic when fighting heartworm disease.

Lack of appetite (anorexia) or weight loss heartworm treatment

It’s terrifying to think about, but a dog with heartworm disease has such little energy that even activities such as eating become too exhausting.

Difficulty breathing or rapid breathing

In addition to coughing, the parasitic infestation can also make breathing difficult as the heartworms multiply in the lungs and surrounding veins.

Allergic reaction

Allergic reactions are more common in cats, but some dogs may show allergy symptoms from the worms.

Bulging chest

Pet owners may notice that their dog’s chest is bulging due to heartworm disease. This is due to the fluid buildup from the parasitic infestation as well as rapid weight loss from not having the energy to eat.


If the heartworms reproduce and mature without proper treatment, they can cause a blockage of blood flow. This blockage is known as caval syndrome or vena cava syndrome and can lead to collapse. More often than not, death usually follows within days.

Additional symptoms of canine heartworm disease include:

  • Increased blood pressure
  • Nosebleeds
  • Secondary pneumonia
  • Excessive sleeping or unexplained lethargy

Although rare, seizures, blindness, and lameness may occur if the parasite infestation moves to the brain or eyes.

Additionally, some of the symptoms of canine heartworm disease are non-specific. In other words, they are also symptoms of a number of other diseases thus making it even more difficult to diagnose.

Diagnosing Heartworm in Dogs

If you suspect your dog may have heartworms, it is important to get it to a veterinarian right away for a proper diagnosis.

In the majority of cases, one or two basic blood tests, as well as a urinalysis, can often determine whether your dog is heartworm positive. Additional tests, which we will discuss shortly, may be necessary to determine the condition of the dog and maturity of the adult worms.

blood test heartworm treatment

Heartworm Test – Antigen Test

The antigen test is the most common blood test used. It detects antigens (proteins) that adult heartworms produce. Also, the antigen test can test positive even if the dog does not have microfilariae present in the bloodstream. For these reasons, it is the preferred method for an accurate diagnosis.

Additional Blood Tests

Other blood tests such as a complete blood count (CBC), a blood chemistry panel, and additional blood tests for liver and kidney function may also be administered in order to determine the state of the organs prior to treatment.

Chest X-Rays

A radiograph, or chest x-ray, may be necessary in order to determine the heart, lungs, and pulmonary vessels. This will help veterinarians predict any complications from treatment prior to them happening.


An electrocardiogram (ECG or EKG) may be necessary to detect abnormalities in heart rhythms which allows veterinarians to know whether or not it is safe for the dog to undergo treatment.


An echocardiography is an ultrasound of the heart. An echocardiography allows a veterinarian to see the status of the heart as well as the heartworms.

Heartworm Treatment for Dogs

If your dog receives a positive diagnosis for heartworm disease, treatment is mandatory and should happen immediately. Heartworms will not die off on their own.

Diagnosing and treating heartworm disease early on is the most effective way to prevent permanent damage. However, this is easier said than done since symptoms often don’t appear for six or seven months.

Furthermore, heartworm treatment does not come without its own set of risks which is yet another reason why preventing canine heartworm disease is imperative.

Melarsomine Dihydrochloride (Immiticide)

First, dogs with heartworm disease will receive any necessary medications to stabilize their condition.

Once stable, treatment can begin. In order to treat heartworm disease, the heartworms need to be killed off. Veterinarians will administer an injectable drug called melarsomine dihydrochloride (immiticide).

The injections are either a two-dose or three-dose process and are given every 30 days. The three-dose treatment is most effective because it doesn’t kill off too many adult worms at one time which can lead to circulatory shock in the dog.

Most likely your dog will require hospitalization when the injections are administered so that the veterinarian can keep a close watch on any potential side effects.

Additionally, veterinarians will prescribe drugs such as prednisone and doxycycline to avoid a negative reaction from the worms dying off.

Melarsomine Dihydrochloride Warnings

The active ingredient in Melarsomine that kills both mature and immature heartworms is arsenic. As you can imagine, this arsenic-based compound does not come without potential dangers. It is imperative that the drug is administered by a trained professional and the dog is closely monitored after receiving the medication.

Melarsomine Dihydrochloride Side Effects

There are a number of severe possible side effects of Melarsomine. The drug is considered one which has a “low margin of safety.” However, letting the heart disease go untreated is not an option.

Possible side effects include:

  • Pain at the injection site
  • Swelling at the injection site
  • Firm nodules that may never go away
  • Coughing
  • Gagging
  • Depression
  • Lethargy
  • Lack of appetite
  • Fever
  • Lung congestion
  • Vomiting

Side effects that are less commonly seen but still exist:

  • Excessive drooling
  • Panting
  • Diarrhea
  • Coughing up blood
  • Abnormal heart rhythms
  • Death

As you can see, the medication to treat canine heartworm disease is incredibly intense. Thus all the more reason why pet owners should prevent the disease at all cost.

Treatment to Kill Off the Microfilariae

Approximately one month after the treatment to kill off the adult worms, your veterinarian will administer the treatment to kill the microfilariae (baby heartworms).

It is possible that your dog will need to stay in the hospital for the following day in order to be closely monitored for any side effects from the drug.

Once this treatment is completed, your dog will begin on a heartworm prevention medication.

Additional Medication for Heartworm Treatment

It is possible that additional antibiotics will be necessary based on your dog’s condition.heartworm treatment

Doxycycline for Dogs

In some cases, veterinarians may use an antibiotic called Doxycycline before starting the immiticide treatment. This step is an extra precaution in case a bacteria known as Wolbachia is present. Wolbachia can reduce the results of the immiticide treatment so doxycycline is used first.

Additionally, heart medications such as ACE-inhibitors, beta-blockers or cardioglycosides, as well as diuretics and diet changes may be required.


In some cases, veterinarians may be able to use ivermectin to treat dogs mildly affected with a heartworm infection. Ivermectin is an anti-parasite and while it doesn’t kill the heartworms, it shortens their lifecycles, sterilizes them, and prevents infections from forming.

Exercise Restriction

Before, during, and for at least one month after treatment for canine heartworm disease, it is imperative to keep your dog inside and strictly control any sort of exercise.

A few days after treatment the adult worms start to die off and begin to decompose. As their bodies decompose, they move to the lungs and into tiny blood vessels. Eventually, the dog’s body reabsorbs the fragments.

Most post-treatment complications happen in this dangerous stage making it absolutely necessary for the dog to remain extremely calm so that the body can work efficiently.


In critical cases of heartworm disease, surgery may be necessary in order to remove the worms from the heart and blood vessels of the lungs.

Follow Up Antigen Test

Approximately six months following the last round of heartworm treatment, a follow-up test (generally called an antigen test) will be performed in order to confirm that all of the heartworms have been killed off.

Heartworm Treatment Cost

The most effective treatment for canine heartworm disease involves a series of tests including an extensive pre-treatment work, blood work, and testing in order to determine the severity of the parasitic infestation.

Once the veterinarian has a full understanding of the necessary treatment, the injections and potentially additional medication can begin.

While extremely important, the pre-treatment work can be quite expensive, often reaching approximately $1,000.

In some parts of the United States, the injections alone are around $300.

Pet owners should consult with their veterinarian as far the best way to treat their dog.

Prognosis for Treatment of Heartworm in Dogs

With carefully monitored treatment, the prognosis for the treatment of heartworms is usually very positive. Many dogs will return to their lively selves, gain back the weight lost, and continue to live a long healthy life.

However, it should be noted that dogs who once suffered from heart disease are still at risk of contracting it again. It is imperative that pet owners start their dog on a heartworm preventative as soon as their vet tells them it is safe to begin.

heartworms in dogs

Heartworm Prevention for Dogs

The treatment for canine heartworm disease can be a long, difficult process for dogs to go through. As you may have guessed, we are big advocates of preventing heartworm from occurring in the first place.

Luckily, the prevention of heartworms is absolutely possible. In fact, pet owners may be surprised at just how safe, affordable, and easy heartworm preventative is to administer for their dogs.

Heartworm Medicine for Dogs

Heartworm preventative comes in a few different forms. Pet owners can choose from monthly pills, monthly topicals that are placed on the skin, and a six-month injectable product available. You may be familiar with brands such as Heartgard or K9 Advantix.

Medication for heartworm prevention is based on the dog’s weight and tends to be between $35 to $80 per year. Compared to the treatment costs for heartworm disease, there really is no comparison.

Some pet owners do not want to use a heartworm preventative. In these cases, pet owners can make sure that their dog is being regularly tested throughout heartworm season.

Routine Heartworm Screenings

It should be noted that heartworm prevention medication is not 100% effective, especially if a dosage is missed or used according to the label instructions. For this reason, routine heartworm screenings are necessary in order to ensure that your dog is heartworm free.

Alternative / Natural Heartworm Treatment

Before we dive into natural alternatives to conventional heartworm treatment, we need to remind you that these treatments should not be attempted without being monitored by a holistic veterinarian.

Heartworm disease is not something that should attempt to do at home by themselves. To find a holistic vet, check out ahvma.org


There is an herbal remedy called HWF from the company Amber Technology. (By law they are not allowed to say that the formula treats heartworm which is why the name is HWF) On their site, the formula states it can support the heart by cleaning the cardiovascular system of unwanted substances.

The remedy contains the following ingredients:

  • Black seed
  • Hops flowers
  • Apricot kernel extract
  • Hawthorn berries
  • Garlic
  • Sheep sorrel
  • Grapefruit seed extract

Holistic Veterinarian Dr Deva Khalsa’s Remedy

Holistic veterinarian Dr Deva Khalsa has formulated the following homeopathic remedy for effectively treating heartworms:

Croton tiglium 9x, 20x, 30x, 200x

Lycopersicum esculentum 9x, 20x, 30x

Tanacetum 9x, 20x, 30x

Allium cepa 9x, 20x, 30x, 200x

Allium sativum 9x ,20x, 30x, 200x

Dr. Khalsa recommends mixing all of these remedies together and administering a few drops orally, twice a day for three months.

Heartworm tests should be run twice a month to monitor progress.

For very sick dogs, Dr. Khalsa recommends using the above treatment plan along with Crataegus (Hawthorn) tincture. The Crataegus (Hawthorn) tincture can help strengthen the heart.

Additionally, CoQ10 (30 to 100mg twice a day) can help boost the metabolism of the heart and detoxify the dog’s body.

Black Walnut

There are several holistic products that use the powerful herb, black walnut. While the products do have effective results, they come with risky side effects.

The strong tannins of black walnut cause vomiting and diarrhea.
It should be used with caution and with monitoring from a holistic veterinarian.

Detoxifying After Heartworm Treatment

A veterinarian and holistic veterinarian will be able to provide accurate and effective guidance as to the best way to treat your dog.

If conventional medication is used, pet owners should consider detoxing their dog after treatment. With these homeopathic remedies, less collateral damage can be done regardless of whether conventional or holistic treatment is used.

Arsenicum Album

Using Arsenicum Album 6C twice a day for at least a month can help detoxify the body after treatment.

Milk Thistle Seed dandelion for dogs heartworm treatment

Using milk thistle seed may help cleanse and tone the liver after conventional treatment.


Using dandelion can also help cleanse and tone liver as well as provide support for kidney health.

Can Humans Get Heartworms?

Before closing out on the topic of heartworms, we want to address this common question. According to Sheldon Rubin, 2007-2010 president of the American Heartworm Society, in rare cases, heartworms have infected people. However, the heartworms do not complete their lifecycle.

The Heartworm: Treatable But More Importantly, Preventable!

We sincerely hope that your beloved dog never gets a positive heartworm diagnosis. The treatment process can truly take a toll on your pup. However, when receiving a heartworm disease diagnosis, treatment is absolutely necessary.

Luckily, there are ways to prevent this silent killer from ever stepping into your dog’s life. Taking the necessary precautions to prevent the disease and scheduling regular screenings during heartworm season can make a life-changing difference for your dog.

Furthermore, knowing the signs of heartworm disease and symptoms to keep an eye out for can better ensure that if your dog does contract heartworms, it can be treated early on before permanent damage is done.

We know you want what’s best for your dog. Understanding heartworm disease is an important step in being able to give your pup the best life possible.

heartworm treatment in action


Can my dog get heartworms from another dog?

How will I know if my dog has heartworms?

What types of heartworm treatment is available for my dog?

How much will it cost to get rid of my dog’s heartworms?

Can I get heartworms from my dog?


7 Heartworm Symptoms in Dogs


Natural Heartworm Treatment For Dogs, Can It Be Done?

5 Natural Heartworm Treatment Alternatives






www.petsandparasites.org › Dog Owners


7 Heartworm Symptoms in Dogs


Natural Heartworm Treatment For Dogs, Can It Be Done?

5 Natural Heartworm Treatment Alternatives


About the author

Chelsea Hunt-Rivera

Chelsea Rivera is a Dedicated Pet Parent who loves to create amazing content for pet owners and is helping change pet wellness as the Head of Content for Honestpaws.com.