Flea, tick & heartworm Dogs

ProHeart for dogs

An injection that prevents heartworm for 6 or 12 months and treats hookworms. [1]

Last reviewed: October 2026 · 3 sources · see sources

Quick answerProHeart (moxidectin (injectable)) is a prescription, given at the clinic medicine for dogs. It kills heartworm larvae, and the shot slowly releases the drug over months. The most common side effects: injection-site irritation, mild vomiting or diarrhea, drooling and low energy.

Key facts

Generic nameMoxidectin (injectable)
Common brand namesProHeart 6, ProHeart 12
Used inDogs
TypeFlea, tick & heartworm
Prescription?Prescription, given at the clinic
Typical US priceNot listed (no reliable public source)

What it's used for

An injection that prevents heartworm for 6 or 12 months and treats hookworms. [1]

How it works

It kills heartworm larvae, and the shot slowly releases the drug over months. [1]

Side effects and cautions

Common side effects: Injection-site irritation, mild vomiting or diarrhea, drooling and low energy. Serious allergic reactions are rare. [1]

Use with care: Not for sick, frail or underweight dogs. Age minimums differ for the 6- and 12-month versions. [1] [2]

Call your vet right away if your pet has trouble breathing, facial swelling, hives, collapse, or any side effect that is severe or getting worse.

About dosingDosing is your vet's call. We don't list doses because the right amount depends on your pet's weight, age, health and other medicines. Don't change a dose or stop a medicine without asking your vet, and never give a pet medicine meant for people unless your vet tells you to [3].

What it costs

We don't list a price for this one because we couldn't find a reliable public source. Ask your vet or pharmacy for a quote; prices depend on your pet's size, the dose and where you fill it.

ProHeart FAQ

What is ProHeart used for in dogs?

An injection that prevents heartworm for 6 or 12 months and treats hookworms.

What are the side effects of ProHeart?

Injection-site irritation, mild vomiting or diarrhea, drooling and low energy. Serious allergic reactions are rare.

Does ProHeart need a prescription?

Yes. It's prescription-only and is usually given at the vet clinic.

How much ProHeart should I give my pet?

Only your veterinarian can tell you. The right dose depends on your pet's weight, health and other medicines, so we don't list doses. Never give a pet a medicine prescribed for a person or another animal without asking your vet.

Related medications

Related cost guides

This page is general information for pet owners, not veterinary advice. Talk to your vet about your own pet.

Sources (3) — tap to show
  1. VCA Animal Hospitals – Moxidectin (injectable) (veterinary drug handout)
  2. FDA – Keep worms out of your pet's heart
  3. FDA – Frequently asked questions about animal drugs