Medication comparison

Ivermectin vs ProHeart: what's the difference?

How Ivermectin and ProHeart compare: what each is for, how it works, side effects and cost, side by side.

Last updated: October 2026 · 3 sources · see sources

Quick answerHeartgard is a monthly preventive given at home; ProHeart is a shot at the clinic that protects for 6 or 12 months. [1][2]

Side by side

Ivermectin vs ProHeart compared
IvermectinProHeart
Generic nameIvermectinMoxidectin (injectable)
Brand namesHeartgard, Heartgard Plus, Tri-HeartProHeart 6, ProHeart 12
ForDogs and catsDogs
PrescriptionPrescriptionPrescription, given at the clinic
Used forMainly a monthly heartworm preventive. Vets also use it for mites and some worms. [1]An injection that prevents heartworm for 6 or 12 months and treats hookworms. [2]
How it worksAt preventive doses it kills young heartworm larvae before they can grow into adult worms. [1]It kills heartworm larvae, and the shot slowly releases the drug over months. [2]
Common side effectsWell tolerated at heartworm-prevention doses. Higher doses can cause wobbliness, tremors, dilated pupils and drooling. [1]Injection-site irritation, mild vomiting or diarrhea, drooling and low energy. Serious allergic reactions are rare. [2]
Use with careCollies, sheepdogs and related breeds can be very sensitive at high doses (MDR1 gene). Dogs need a negative heartworm test first. [1]Not for sick, frail or underweight dogs. Age minimums differ for the 6- and 12-month versions. [2]
Typical priceMonthly heartworm preventive, as listed on owner bills: $6–$18 a dose [3]No reliable published price
Full guideIvermectin (Heartgard) guideProHeart guide

Key differences

Which one is right for my pet?

That is a call for your vet. They weigh your pet's age, weight, other health problems, other medicines and what you can realistically give at home.

Switching from Ivermectin to ProHeart is common, but do it only with your vet's plan.

About dosesWe don't list doses. The right amount depends on your pet's weight, health and other medicines, and only your vet can set it.

Common questions

What is the difference between Ivermectin and ProHeart?

Heartgard is a monthly preventive given at home; ProHeart is a shot at the clinic that protects for 6 or 12 months.

Is Ivermectin better than ProHeart?

Neither is better for every pet. Your vet chooses based on your pet's species, age, health history, other medicines and what you can manage at home.

Can my pet take Ivermectin and ProHeart together?

Only if your vet says so. Some medicines in the same family should not be combined, and others are often used together. Always check before adding or switching.

Do Ivermectin and ProHeart need a prescription?

Ivermectin: Yes. It needs a prescription from a veterinarian. ProHeart: Yes. It's prescription-only and is usually given at the vet clinic.

How much do Ivermectin and ProHeart cost?

Ivermectin: Monthly heartworm preventive, as listed on owner bills $6–$18 a dose. ProHeart: no reliable published price. Prices vary by pet size, pharmacy and clinic.

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

Sources (3) — tap to show
  1. VCA Animal Hospitals – Ivermectin (veterinary drug handout)
  2. VCA Animal Hospitals – Moxidectin (injectable) (veterinary drug handout)
  3. VetReceipt – Dog heartworm treatment cost (owner bills)