What Is The Best Treatment For Heartworms In Dogs?

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If you're a dog owner, just hearing the word heartworm can be scary. And honestly, it should be—heartworms are no joke. They can seriously mess with your pup's health, and if left untreated, they can even be fatal. But here’s the good news: heartworm disease is treatable, and even better, it’s preventable. So, what is the best treatment for heartworms in dogs? Let’s dive into it all—from symptoms to vet-approved treatment options and how to support your furry friend through it all.

Understanding Heartworms
What Are Heartworms?
Heartworms (Dirofilaria immitis) are long, spaghetti-like parasites that live in the lungs, heart, and blood vessels of infected dogs. Gross, right? But even worse, they can cause severe damage over time, leading to organ failure and death if not caught early.

How Do Dogs Get Infected?
Heartworms are spread by mosquitoes. When a mosquito bites an infected animal, it picks up immature heartworm larvae. When it bites your dog, it injects the larvae under the skin. Those tiny invaders travel through your dog’s bloodstream and grow into adult worms inside the heart ...
... and lungs. It’s a slow, sneaky attack that can go unnoticed for months.

Why Are Heartworms Dangerous?
The adult worms can live for 5–7 years in dogs, causing blockages in the heart and lungs. This puts enormous stress on your dog’s cardiovascular system and can eventually lead to heart failure. It’s a silent killer—symptoms often don’t show up until the disease is advanced.

Recognizing the Signs of Heartworm Disease
Early Stage Symptoms
Mild, persistent cough

Fatigue after moderate activity

Decreased appetite

Weight loss

At this stage, it’s easy to mistake heartworms for just being “out of shape” or “getting older.”

Advanced Symptoms
Swollen belly from fluid buildup

Difficulty breathing

Collapsing after physical exertion

Pale gums and dark-colored urine

Once symptoms progress, your dog may already be in a life-threatening stage.

Importance of Timely Diagnosis
The earlier heartworms are caught, the better the chances of full recovery. Annual heartworm tests are crucial—even if your dog is on preventatives.

Diagnostic Tests for Heartworm in Dogs
Blood Antigen Test
This is the most common test. It detects proteins released by adult female heartworms. It's quick and accurate, but it won’t pick up infections less than 6 months old.

Microfilariae Detection
This test looks for baby heartworms (microfilariae) in your dog’s bloodstream under a microscope. If they’re found, it's a clear sign your dog is infected.

Chest X-Rays and Ultrasounds
In more serious cases, imaging may be needed to see the level of damage to your dog’s lungs and heart. This helps vets plan the best course of treatment.

Treatment Options for Heartworm in Dogs
Melarsomine Dihydrochloride (Immiticide)
This is the go-to medication most vets use to kill adult heartworms. It's an arsenic-based injectable drug given deep into the back muscles over a series of injections. While it may sound intense—and it kind of is—it’s highly effective. The typical protocol involves one injection, followed by two more spaced 24 hours apart about a month later. This kills off adult worms slowly to prevent sudden blockage of blood vessels.

Doxycycline Therapy
Before starting melarsomine, most vets prescribe doxycycline—an antibiotic that targets a bacteria called Wolbachia that lives inside heartworms. Killing this bacteria makes the worms weaker and less inflammatory, reducing the chance of complications during treatment.

Corticosteroids and Supportive Care
To help reduce inflammation caused by dying worms, your vet might also add corticosteroids to the mix. These drugs help minimize the risk of dangerous side effects like blood clots and lung inflammation.

Exercise Restriction
This is probably one of the hardest parts for both dogs and their humans. Once treatment starts, your dog’s activity should be restricted. No walks, no running, no fetch. Why? Because too much activity can make worms die too fast, causing blockages and severe reactions. Think strict crate rest for weeks or even months.

Hospitalization vs. Home Treatment
Some cases—especially severe ones—might require your dog to stay at the vet for observation during the treatment process. Others can be managed from home with regular vet visits. It all depends on how sick your pup is when treatment begins.

Step-by-Step Heartworm Treatment Protocol
Stabilizing Your Dog Before Treatment
If your dog is severely infected or already showing serious symptoms, your vet may recommend stabilizing their condition first. This might involve medication to support heart function, reduce inflammation, and address any secondary infections.

Administering Medications
Once stabilized, your vet will begin the heartworm-killing phase. This includes a combination of doxycycline, heartworm preventatives, and melarsomine injections given over several weeks or months.

Post-Treatment Monitoring and Recovery
Even after the last injection, you’re not quite done. Your vet will schedule follow-ups and blood tests to ensure all worms are gone. You'll also need to watch closely for any signs of complications like coughing, lethargy, or breathing issues.

Surgical Removal in Severe Cases
When is Surgery Necessary?
If your dog has a massive number of worms, especially in the heart, surgical removal might be the only option. This is known as caval syndrome—a critical, life-threatening condition where worms physically block blood flow.

Risks and Recovery
Surgery is risky and expensive, but for dogs in this advanced stage, it’s often their only shot. Recovery involves careful post-op monitoring and supportive care.

Prevention is Better Than Cure
Monthly Preventatives
Heartworm disease is totally preventable with monthly medications like Heartgard, Interceptor, or Trifexis. These come in chewable or topical forms and kill larvae before they can grow into adult worms.

Injectable Preventatives
For those who struggle with monthly meds, there’s ProHeart—an injectable preventative that lasts either 6 or 12 months. Convenient and highly effective.

Year-Round Protection Advice
Even if mosquitoes disappear in winter, vets recommend keeping your dog on preventatives year-round. All it takes is one bite during a warm spell to restart the cycle.

Natural or Home Remedies: Do They Work?
The Myths Around Natural Cures
You might see online claims about garlic, black walnut, or herbal cleanses curing heartworms. Let’s be clear: there is no scientific proof that these work. In fact, they can delay real treatment and cause more harm.

Why You Should Stick to Vet-Approved Methods
Heartworm disease is not something to DIY. Trust your vet. The approved meds are tested, backed by research, and safe when used properly. Order heartworm tablets for dogs!

Pet Insurance and Payment Plans
Some pet insurance plans cover heartworm treatment, especially if you’re already enrolled before your dog gets infected. Many vets also offer payment plans or financing options to ease the financial burden.

How to Support Your Dog During Treatment
Dietary Tips
Feed your dog a balanced, high-quality diet to keep their immune system strong. No need for drastic diet changes unless your vet advises.

Reducing Stress
Create a calm, quiet space for your dog to rest. Limit noise, visitors, and excitement. Remember—less stress equals safer recovery.

Monitoring for Side Effects
Stay alert for signs like vomiting, diarrhea, or sudden lethargy. These could be reactions to the medication or dying worms. Contact your vet if anything seems off.