Does Heartgard Plus Require a Prescription in the USA?
Yes — in the United States, Heartgard Plus is regulated as a prescription-only veterinary medication because it contains ivermectin, which is a heartworm preventative. The FDA requires a prescription for any product that prevents heartworm disease, on the basis that dogs should be tested for existing heartworm infection before starting prevention.
However, in Australia, Heartgard Plus is classified as an OTC product by the APVMA. No prescription is required to purchase or sell it. Australian retailers can therefore supply genuine Heartgard Plus directly to US and Canadian dog owners without requiring a vet script. For a full explanation of why Australian prices are lower, see why pet medications are cheaper from Australia.
What Is Heartgard Plus?
Heartgard Plus is a monthly chewable beef-flavored tablet for dogs made by Boehringer Ingelheim. It contains two active ingredients:
- Ivermectin — prevents heartworm disease by eliminating heartworm larvae before they develop into adult worms
- Pyrantel pamoate — treats and controls roundworms and hookworms
Heartgard Plus is one of the most widely used heartworm preventatives in the USA, with an extensive safety record across millions of dogs.
Why Is Heartworm Prevention So Important?
Heartworm disease is transmitted by mosquitoes and can cause severe, potentially fatal lung, heart, and organ damage in dogs if untreated. Adult heartworms can reach 12 inches in length and live in the heart and pulmonary arteries. Treatment of adult heartworm infection is expensive, lengthy, and hard on the dog — prevention is far simpler and cheaper.
Heartgard Plus works by clearing heartworm larvae from the body within a 30-day window after mosquito exposure. Monthly dosing is essential to maintain protection.
Heartgard Plus vs Heartgard: What's the Difference?
Original Heartgard contains only ivermectin, covering heartworm prevention only. Heartgard Plus adds pyrantel pamoate, extending coverage to include roundworm and hookworm treatment. For most dog owners, Heartgard Plus is the better choice since the addition of pyrantel adds meaningful protection at no extra inconvenience.
Does Heartgard Plus Cover Fleas and Ticks?
No. Heartgard Plus covers heartworm, roundworms, and hookworms only. It does not protect against fleas or ticks. Many dog owners combine Heartgard Plus with a dedicated flea and tick product like NexGard or Bravecto for comprehensive coverage. Alternatively, Simparica Trio or NexGard Spectra cover heartworm, intestinal worms, fleas, and ticks all in one monthly chew — read our NexGard Spectra vs Simparica Trio comparison to see which suits your dog.
Choosing the Right Heartgard Plus Size
Heartgard Plus is available in three weight ranges:
- Small dogs: up to 25 lbs (up to 11 kg) — Blue
- Medium dogs: 26–50 lbs (12–22 kg) — Green
- Large dogs: 51–100 lbs (23–45 kg) — Brown
Heartgard Plus is suitable for puppies from 6 weeks of age.
Important Safety Note: Heartworm Testing
If your dog has not been on consistent monthly heartworm prevention, it's strongly recommended to have them tested for adult heartworm infection before starting Heartgard Plus. Giving a heartworm preventative to a dog with an active adult heartworm infection can cause a serious reaction.
Is Heartgard Plus Safe for All Dogs?
Heartgard Plus is safe for most dogs. However, some herding breeds (Collies, Australian Shepherds, Shetland Sheepdogs, and others) carry a genetic mutation called MDR1 (ABCB1) that makes them sensitive to ivermectin at higher doses. At the standard Heartgard Plus dose, this is generally not a concern — but if your dog is an MDR1-sensitive breed, consult a veterinarian if you have specific concerns.
Is It Legal to Import Heartgard Plus From Australia?
For a full breakdown of the legal framework around importing pet medications from Australia, see our article on whether it's legal to import pet medications from Australia.
Where to Buy Heartgard Plus Without a Prescription
Smartway Pet Supplies stocks genuine Heartgard Plus for all three dog sizes, shipped directly to the USA and Canada in original Boehringer Ingelheim packaging. No prescription required.
Smartway Pet Supplies
Pet Care Specialist — Smartway Pet Supplies
A member of the Smartway team, writing practical guides to help US and Canadian pet owners choose the right parasite prevention products for their pets.
About Smartway Pet Supplies →
