Interceptor Plus vs Heartgard Plus – Which Parasite Preventive Is Better?

Is your dog protected from heartworms only, or from the intestinal worms your dog may also be exposed to?

Not every heartworm medication covers the same intestinal parasites. Some products focus on heartworms, roundworms, and hookworms, while broader options may also cover whipworms or tapeworms. Choosing the right dog heartworm preventive depends on your dog’s parasite risk, breed, age, weight, health history, and your veterinarian’s recommendation.

Choosing the right heartworm preventive is more than choosing a familiar brand name. It means understanding parasite coverage, active ingredients, side effects, prescription requirements, and whether your dog needs basic or broader internal parasite protection.

Did you know? According to AVMA reporting on American Heartworm Society survey data, the number of dogs testing positive for heartworm has increased by well over 50,000 with each three-year survey cycle. [source]

Two of the most widely prescribed options, Interceptor Plus and Heartgard Plus, both help prevent heartworm disease and treat or control certain intestinal worms. Their biggest difference is coverage: Interceptor Plus includes whipworm and tapeworm coverage, while Heartgard Plus does not.

In this guide, we’ll compare Interceptor Plus vs Heartgard Plus by parasite coverage, ingredients, cost, side effects, breed considerations, switching guidance, and common questions like does Heartgard Plus kill tapeworms and what does Interceptor Plus cover.

Interceptor Plus vs Heartgard Plus: Simple Coverage Comparison

Here is the simplest way to compare Interceptor Plus and Heartgard Plus for dogs.

What Does Interceptor Plus Cover for Dogs?

Interceptor Plus protects dogs from five types of parasites using milbemycin oxime and praziquantel. It helps prevent heartworm disease and treats or controls adult roundworms, hookworms, whipworms, and tapeworms listed on the product label.

Interceptor Plus Chew for Dogs

Elanco

From $12.39

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It may be a good fit for pet owners who want broader internal parasite coverage in one monthly chew, especially if their dog has exposure to environments where intestinal worms are a concern.

What are the active ingredients in Interceptor Plus?

Interceptor Plus contains two active ingredients:

• Milbemycin oxime: helps prevent heartworm disease and treats or controls roundworms, hookworms, and whipworms.
• Praziquantel: treats and controls tapeworms listed on the product label.

This combination gives Interceptor Plus broader worm coverage than Heartgard Plus.

Does Interceptor Plus have ivermectin?

No. Interceptor Plus does not contain ivermectin. Its active ingredients are milbemycin oxime and praziquantel. This is one reason some veterinarians may consider it when a pet parent asks about non-ivermectin heartworm prevention for dogs.

What parasites does Interceptor Plus protect against?

Interceptor Plus offers 5-in-1 parasite protection. It covers:

• Heartworms
• Roundworms
• Hookworms
• Whipworms
• Tapeworms

Because Interceptor Plus includes tapeworm and whipworm coverage, it is often compared against Heartgard Plus by pet owners asking what worms Interceptor Plus kills and what Heartgard Plus does not cover.

Does Interceptor Plus kill tapeworms?

Yes. Interceptor Plus contains praziquantel, which treats and controls adult tapeworms listed on the label. However, tapeworm prevention may also require flea control because dogs commonly get Dipylidium tapeworms by swallowing infected fleas. If fleas are part of your dog’s risk profile, ask your veterinarian about pairing heartworm prevention with appropriate flea and tick medications.

Does Interceptor Plus kill whipworms?

Yes. Interceptor Plus treats and controls adult whipworms. This is one of the main coverage differences between Interceptor Plus and Heartgard Plus.

When can I start Interceptor Plus for my dog?

Dogs as young as 6 weeks old and weighing at least 2 pounds can start Interceptor Plus when prescribed by a veterinarian. Always dose based on your dog’s current weight and label directions.

What form does Interceptor Plus come in, and how often is it given?

Interceptor Plus is a chicken-flavored chewable tablet given once a month. Monthly dosing helps maintain consistent protection when used exactly as directed by your veterinarian.

Does Interceptor Plus have side effects or breed restrictions?

Interceptor Plus may cause side effects such as vomiting, diarrhea, decreased activity, or appetite changes in some dogs. Contact your veterinarian if your dog has persistent symptoms, severe symptoms, or a history of medication sensitivity.

For herding breeds such as Collies, Australian Shepherds, and Shelties, avoid making medication decisions based on breed alone. Interceptor Plus is ivermectin-free, but dogs with possible MDR1 sensitivity should still receive parasite medications only under veterinary guidance. FDA-approved heartworm preventives are generally used at specific labeled doses, and your veterinarian can help determine whether MDR1 testing or a specific product is appropriate for your dog.

Compared with basic heartworm meds, Interceptor Plus may offer greater value for dogs that need tapeworm and whipworm coverage in addition to heartworm, roundworm, and hookworm protection.

What Does Heartgard Plus Cover for Dogs?

Heartgard Plus is a monthly prescription chewable used for heartworm prevention in dogs. It also treats and controls roundworms and hookworms. It is known for its focused coverage, beef-flavored chew format, and long-standing use in monthly canine heartworm prevention.

Heartgard Plus Chew for Puppies/Small dogs (Ivermectin/Pyrantel), up to 25 lbs

Boehringer Ingelheim

(6)

From $11.59

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Heartgard Plus Chew for Medium Dogs (Ivermectin/Pyrantel), 26-50 lbs (Green Box)

Boehringer Ingelheim

(3)

From $13.99

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Heartgard Plus Heartworm Prevention Chews for Large Dogs 51-100 lbs

Boehringer Ingelheim

(5)

From $15.99

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What are the active ingredients in Heartgard Plus?

Heartgard Plus contains two active ingredients:

• Ivermectin: helps prevent heartworm disease by eliminating susceptible heartworm larvae.
• Pyrantel: treats and controls roundworms and hookworms.

Heartgard Plus does not contain praziquantel, which is why it does not treat tapeworms.

What parasites does Heartgard Plus protect against?

Heartgard Plus protects dogs from:

• Heartworms
• Roundworms
• Hookworms

If your dog is at lower risk for tapeworms or whipworms and your veterinarian mainly wants heartworm, roundworm, and hookworm coverage, Heartgard Plus may be a suitable option.

Does Heartgard Plus kill tapeworms?

No. Heartgard Plus does not kill tapeworms. It covers heartworm prevention and treats or controls roundworms and hookworms. If your dog has tapeworm risk, your veterinarian may recommend a product with praziquantel, such as Interceptor Plus, or another tapeworm treatment.

Does Heartgard Plus kill whipworms?

No. Heartgard Plus does not kill or control whipworms. If your dog needs whipworm coverage, ask your veterinarian whether Interceptor Plus or another appropriate deworming option is a better fit.

What worms does Heartgard Plus kill?

Heartgard Plus treats and controls roundworms and hookworms. It does not treat tapeworms or whipworms.

At what age can dogs start using Heartgard Plus?

Dogs can start Heartgard Plus at 6 weeks of age when prescribed by a veterinarian. Follow the product label and your veterinarian’s instructions for the correct dose.

What form does Heartgard Plus come in, and how is it given?

Heartgard Plus is available as a beef-flavored chewable given once per month. Many dogs take it like a treat, which can make monthly prevention easier for pet parents.

Does Heartgard Plus have side effects or breed considerations?

Heartgard Plus side effects are uncommon but may include digestive upset such as vomiting or diarrhea. Because it contains ivermectin, pet parents with MDR1-risk breeds should use it exactly as prescribed and ask their veterinarian whether testing or a different product is appropriate. Do not give extra doses or use off-label ivermectin products unless your veterinarian specifically directs you to do so.

Heartgard Plus may be a cost-effective choice for dogs that need essential heartworm, roundworm, and hookworm protection without tapeworm or whipworm coverage.

What Is the Difference Between Interceptor Plus and Heartgard Plus?

The main difference between Interceptor Plus and Heartgard Plus is parasite coverage. Interceptor Plus covers heartworms, roundworms, hookworms, whipworms, and tapeworms. Heartgard Plus covers heartworms, roundworms, and hookworms, but it does not cover tapeworms or whipworms.

Interceptor Plus is also ivermectin-free, while Heartgard Plus contains ivermectin. For dogs with known medication sensitivities, MDR1 concerns, or breed-related questions, the safest choice is the one your veterinarian recommends based on your dog’s health history and risk profile.

Interceptor Plus vs Heartgard Plus: Which One Is Better?

• Choose Interceptor Plus if your dog needs broader internal parasite coverage, especially tapeworm or whipworm coverage.
• Choose Heartgard Plus if your veterinarian recommends focused heartworm, roundworm, and hookworm protection.
• Ask your veterinarian first if your dog has MDR1 risk, known medication sensitivities, missed doses, or a history of intestinal worms.

Interceptor vs Interceptor Plus: What is the difference?

Many pet owners search for Interceptor vs Interceptor Plus. The key is to check the exact product label and active ingredients. Interceptor Plus contains milbemycin oxime plus praziquantel, which adds tapeworm coverage. If you are comparing Interceptor and Interceptor Plus, ask your veterinarian which version matches your dog’s parasite risk.

Heartgard vs Heartgard Plus: What is the difference?

Pet owners also search for Heartgard vs Heartgard Plus. Heartgard Plus contains ivermectin and pyrantel and is labeled for heartworm prevention plus roundworm and hookworm treatment/control. Always confirm the exact product name, active ingredients, and label coverage before switching products.

Transitioning Between Heartworm Medications

Switching between heartworm medications should be done with veterinary guidance so your dog does not have a gap in protection or accidentally receive overlapping doses.

Can I switch from Heartgard Plus to Interceptor Plus?

Yes, your veterinarian may recommend switching from Heartgard Plus to Interceptor Plus if your dog needs broader parasite protection, including tapeworm and whipworm coverage, or if your dog’s health history makes another active ingredient profile preferable.

How do I switch from Heartgard Plus to Interceptor Plus?

To transition safely:

• Wait until the next scheduled dose before giving the new product unless your veterinarian tells you otherwise.
• If you missed a dose or delayed prevention, your vet may recommend a heartworm test before restarting.
• Monitor your dog after the first dose for digestive upset, lethargy, or unusual behavior.

This switch broadens coverage, especially for dogs exposed to dog parks, kennels, rural areas, fleas, or environments where intestinal parasites are more likely.

Is it safe to go from Interceptor Plus to Heartgard Plus?

Switching from Interceptor Plus to Heartgard Plus may be appropriate for some dogs, especially if your veterinarian says your dog only needs heartworm, roundworm, and hookworm coverage. However, Heartgard Plus does not cover tapeworms or whipworms, so the switch narrows your dog’s parasite protection.

How do I switch from Interceptor Plus to Heartgard Plus?

To switch:

• Confirm your dog is still within the monthly coverage window of the last Interceptor Plus dose.
• Give Heartgard Plus at the next scheduled monthly dose time unless your veterinarian advises otherwise.
• Ask your veterinarian whether your dog needs separate monitoring or deworming for tapeworms or whipworms.

This switch is usually best suited for dogs with low intestinal parasite exposure and no history of tapeworm or whipworm problems.

General Guidelines for a Safe Transition

• Always consult your veterinarian before switching heartworm preventives.
• Never give two heartworm preventives at the same time unless your vet specifically tells you to.
• Keep a dosing calendar so your dog stays on a consistent monthly schedule.
• Use your dog’s current weight to choose the correct product size.

Do I need a heartworm test before switching heartworm medications?

If your dog has missed a dose, had a long gap between doses, or is starting heartworm prevention for the first time, your veterinarian may recommend a heartworm test before starting or restarting medication. Annual testing is also commonly recommended because missed doses and delayed dosing can reduce protection.

Why is veterinary consultation essential?

Your veterinarian can help prevent dosing mistakes, identify breed or medication sensitivity concerns, check for current infection risk, and recommend the best option based on your dog’s lifestyle and local parasite exposure.

Where Can I Buy Interceptor Plus or Heartgard Plus?

Both Interceptor Plus and Heartgard Plus are prescription-only medications and can be purchased through the HardyPaw Pet Pharmacy with a valid veterinarian prescription. With an active prescription, you can:

• Select your dog’s correct weight range
• Upload or authorize prescription verification
• Order trusted prescription-based pet medications online
• Set up reorder reminders or auto-ship options when available

Buying through a verified prescription-based pet pharmacy can help reduce the risk of counterfeit, expired, or incorrectly dosed products compared with unclear third-party listings.

Why order from HardyPaw instead of a general retailer?

• Prescription verification: HardyPaw verifies prescription medications before fulfillment.
• Transparent pricing by dog size: Product pages show pricing by weight range.
• Dosing support by weight category: Options are organized for puppies, small dogs, medium dogs, and large dogs.
• Pet-owner-friendly service: Helpful customer support and reorder support make monthly prevention easier to maintain.

Can I set up auto-shipping for monthly doses?

Yes. HardyPaw offers auto-refill and subscription options for many heartworm medications. This can help your dog stay on schedule and reduce the chance of missed monthly doses.

Interceptor Plus or Heartgard Plus: Which Is the Better Heartworm Preventive for Dogs?

Both Interceptor Plus and Heartgard Plus are trusted prescription options, but they are not interchangeable.

• Choose Interceptor Plus if your veterinarian wants broader worm coverage, including tapeworms and whipworms.
• Choose Heartgard Plus if your dog only needs heartworm, roundworm, and hookworm coverage and your veterinarian agrees it is the right fit.
• Ask your veterinarian before choosing either product if your dog has MDR1 risk, seizure history, medication sensitivity, current illness, or a history of missed heartworm doses.

Either way, consistent monthly prevention is important. Heartworm disease can be serious, and prevention is safer and simpler than treatment.

Interceptor Plus vs Heartgard Plus FAQs

Q1. What worms does Heartgard Plus kill, and does it kill tapeworms or whipworms?

Ans. Heartgard Plus treats and controls roundworms and hookworms and helps prevent heartworm disease. It does not kill or cover tapeworms or whipworms. If your dog has tapeworm or whipworm risk, ask your veterinarian whether Interceptor Plus or another deworming option is more appropriate.

Q2. What worms does Interceptor Plus kill, and does it kill tapeworms?

Ans. Interceptor Plus treats and controls adult roundworms, hookworms, whipworms, and tapeworms listed on the product label. It also helps prevent heartworm disease. Its tapeworm coverage comes from praziquantel, one of its active ingredients.

Q3. Does Interceptor Plus kill fleas or ticks, and can it be used with flea or tick treatments?

Ans. No. Interceptor Plus is not a flea or tick medication. Many dogs use heartworm prevention along with flea and tick prevention, but your veterinarian should confirm compatibility based on your dog’s medications, weight, breed, and health history. You can also review flea or tick treatments available through HardyPaw.

Q4. How long does it take for Interceptor Plus or Heartgard Plus to work?

Ans. Monthly heartworm preventives work by eliminating susceptible heartworm larvae acquired during the previous month, which is why on-time dosing is important. For intestinal worms, timing can vary by parasite and product, so follow the product label and your veterinarian’s directions.

Q5. Should I give my dog heartworm medicine all year?

Ans. Yes. Veterinary organizations commonly recommend year-round heartworm prevention because mosquitoes can persist in many regions and missed doses may leave dogs vulnerable.

Q6. Can my dog develop resistance to heartworm medication over time?

Ans. Heartworm resistance is a concern in some areas, but missed or late doses are a major reason preventives fail. Give prevention exactly as directed and keep up with annual heartworm testing.

Q7. Can I buy heartworm prevention without seeing a vet?

Ans. No. Heartworm medications require a veterinarian prescription. Your vet may recommend testing before prescribing prevention, especially if your dog is starting prevention or has missed doses.

Q8. What signs show the heartworm medication is working properly?

Ans. The most reliable confirmation is a negative heartworm test at your dog’s regular veterinary visit. Lack of symptoms alone does not prove your dog is protected because early heartworm disease can be silent.

Q9. Are there natural alternatives to heartworm prevention?

Ans. No natural alternatives are clinically proven to prevent heartworm disease. Use only veterinarian-recommended, FDA-approved heartworm prevention products.

Q10. How does Heartgard Plus compare with NexGard Plus?

Ans. Heartgard Plus focuses on heartworms, roundworms, and hookworms. NexGard Plus is a different combination product that also includes flea and tick coverage. For a deeper comparison, read NexGard Plus vs Heartgard Plus.

Medical References Used

• AVMA: Heartworm incidence climbs despite preventive efforts
• DailyMed drug label database
• American Heartworm Society: Heartworm prevention for dogs
• American Heartworm Society canine guidelines
• Washington State University: MDR1 and heartworm prevention safety
• CDC: About Dipylidium tapeworm infection
• CAPC: Dipylidium caninum guidelines

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