Heartworm Treatment

Black dog giving staff member a hug before xrays

Learning that your pet is heartworm positive can be a scary experience. At Anicira, we work with pet parents to ensure you are well-informed and understand your pet’s treatment plan. Our veterinary team provides compassionate care before, during, and after treatment to ensure your pet is safe and comfortable.

What are heartworms? How did my pet get heartworms?

Heartworms are parasitic roundworms that spread through mosquito bites. Left untreated, it can result in major organ failure and death. Heartworm disease is very common, and pets should be on medication to prevent infection.

If your pet is heartworm positive, limit their activity and keep them confined until after they have received their final treatment and given the all clear by a veterinarian. Strenuous exercise could cause severe complications and even death.

How are heartworms diagnosed?

Heartworms are most commonly detected by a simple in-hospital blood test. A screening test should be performed yearly, even if your dog is on preventatives.

If your dog’s screening test comes back positive, we will run a second confirmatory test before starting treatment. This may be run in-hospital or may need to be sent out to a lab.

Can a heartworm-positive dog spread the infection to other pets in the house? Can I get heartworms?

Heartworms are spread through mosquito bites. They are not contagious from pet to pet. Humans cannot contract heartworms from their pets; however, in very rare cases, humans can develop heartworms after being bitten by an infected mosquito.

Heartworm-positive pets should be isolated from other pets to minimize activity during their heartworm treatment. It is absolutely vital that you limit their activity and keep them confined until receiving their final treatment.

What are the symptoms of heartworms?

Symptoms of heartworms include:

  • Fatigue after exercise and reluctance to exercise
  • Mild cough
  • Decreased appetite
  • Weight loss
  • Heart failure
  • Swollen belly due to excessive fluid in the abdomen

Your pet may not show any symptoms until months or even years after contracting heartworm.

Heartworm Treatment Schedule

After your dog’s diagnosis has been confirmed, we can initiate treatment.

Initial “pre-adulticide treatment”

1. Oral Antibiotics Taken at Home

Your pet will be given a 4-week’s supply of an antibiotic (either doxycycline or minocycline) to kill bacteria that live symbiotically with the heartworms. By killing the bacteria, you will begin to weaken the adult heartworms.

Side effects of antibiotics include:

  • nausea
  • vomiting or gastrointestinal problems.

Please give your pet their medication with food to reduce the risk of these side effects.

2. Oral Preventatives Taken at Home

Your pet will also receive a heartworm preventative medication that they will take every month. This prevents future infection and kills immature heartworms

Side effects of heartworm preventatives are very rare but serious. They include:

  • lethargy
  • vomiting
  • anorexia
  • diarrhea
  • mydriasis
  • ataxia
  • staggering
  • convulsions
  • hypersalivation

First Injection of Melarsomine at Anicira Veterinary Center

The first injection of melarsomine to kill adult heartworms is given approximately 2 months after starting the pre-adulticide treatments. Your pet may be required to stay in the hospital for observation after receiving the injection.

Side effects of melarsomine include:

  • pain, swelling, and tenderness at the injection site
  • fever
  • lethargy
  • a loss of appetite
  • vomiting
  • gagging
  • lung congestion
  • depression

After each injection, your dog will be sent home with oral prednisone. Prednisone is a steroid with anti-inflammatory properties that can help reduce the side effects of the heartworm treatment injection. Your pet will take this at home.

Side effects of prednisone include:

  • increased thirst and urination
  • increased hunger
  • panting
  • lethargy
  • development or worsening of infections
  • vomiting or nausea.

It is best to give prednisone with food to reduce the chance of it irritating your pet’s stomach.

Second Injection of Melarsomine at Anicira Veterinary Center

Your pet will receive a second injection of melarsomine 30 days after their first injection to continue killing adult heartworms. Your pet may be required to stay in the hospital for observation after receiving the injection.

Third Injection of Melarsomine at Anicira Veterinary Center

Your pet will receive a third injection of melarsomine 24 hours after their second injection. Your pet may be required to stay in the hospital for observation after receiving the injection.

Activity restriction post-treatment

Continue exercise restriction for 6- to 8-weeks following last melarsomine injections

Follow-up testing

A year after the initial diagnosis, your pet should be tested again to ensure no heartworms remain. Remember to give your pet their heartworm preventative medication each month to ensure they do not develop heartworms again.

Please contact Anicira, your primary care veterinarian, or an emergency clinic if any of the following occur:

  • Pale gums
  • Severe pain, depression or weakness
  • Vomiting or Diarrhea
  • Labored breathing
  • Decreased appetite for more than 24 hours
  • Lethargy lasting more than 24 hours