Interceptor vs. Interceptor Plus For Dogs: Our Guide To Which Is Better

If you’re looking to control parasites like heartworms, hookworms, roundworms and more in your dogs, you’ll definitely need an anti-parasitic medication like Interceptor or Interceptor Plus. However, you may not be sure which one is right for you. These medications are very similar, after all – so how can you choose the one that’s right for your dog?

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After all, parasites like tapeworms and hookworms can be very damaging to your dog’s quality of life, and cause issues like malnutrition and intestinal diseases. Heartworms can even be life-threatening, causing issues like loss of appetite, lethargy, and even sudden death due to cardiac arrest and congestive heart failure.

In order to keep your dog safe and healthy, you definitely need to provide it with an anti-parasite medication every month to destroy adult parasites, and keep larvae and eggs from developing. Not sure where to start? Got questions?

In this comprehensive guide, we’ll be taking a deep look at all of the differences between Interceptor and Interceptor Plus, and we’ll help you determine which medication will be right for your dog. From the differences between each drug to its key features, pricing, availability and more, we’ll be discussing everything that you need to know to keep your dog safe, and choose the right medication.

We’ll also answer some FAQs about Interceptor, Interceptor Plus, and parasites in general. After you’ve read this article, you’ll have all of the information you need to get the right anti-parasite medication for your dog.

5 Key Differences Between Interceptor And Interceptor Plus

Before we dive into the basics of each medicine, let’s begin by discussing a few of the key differences that you should know about between Interceptor vs. Interceptor Plus.

While these medications are quite similar – and even made by the same company – there are some differences you should be aware of before you make a buying decision. We’ve put together a list of some of the biggest differences between these drugs below, so take a look now.

  • Number of active ingredients – Interceptor uses only a single active ingredient to control parasites in dogs, which is called milbemycin oxime. This drug has been used successfully to control parasites in dogs for nearly 3 decades, and is widely acknowledged as a safe and effective means by which to prevent parasitic infestations from roundworms, hookworms, heartworms, and whipworms.
    Interceptor Plus also uses milbemycin oxime to fight back against these four common parasites. However, it also incorporates praziquantel, which is an effective anti-tapeworm medication, and helps destroy tapeworm larvae before they can gestate and affect your dog.
  • Flavoring – Interceptor, like many other dog medications, comes in a chewable tablet that’s beef-flavored, so it’s easy to feed to your dog. Interceptor Plus, on the other hand, uses a chicken flavor. This may seem like a small consideration, but picking the product with your dog’s favorite flavor will ensure that it eats the entire tablet, and is completely protected from parasites.
  • Minimum age for use – Interceptor can be used in dogs which are as young as four weeks old, while Interceptor Plus is recommended for dogs which are six weeks of age or older. If you are concerned about giving your dog anti-parasite medication as soon as possible, Interceptor may be a better choice for you.
  • Level of parasite protection – Interceptor Plus protects your dog against tapeworms, while Interceptor does not. This is because of the addition of praziquantel, which is included in Interceptor Plus. This means that Interceptor Plus provides a higher overall level of parasite protection.
  • Safety for use on pregnant, lactating females – Interceptor is an older medication, so it has been tested for its safety when used to treat female dogs who are lactating or pregnant. If your dog is breeding, pregnant, may become pregnant, or is lactating, Interceptor may be a better option for you.
    Interceptor Plus, on the other hand, has not yet been tested for its safety in pregnant and lactating females. You should consult with your veterinarian before you attempt to give Interceptor Plus to a pregnant or lactating dog Interceptor Plus.

As you can see, there are quite a few similarities between these two medications, but there are also some key differences which may change your buying decision, based on your dog’s particular needs. Next, let’s discuss each medication in further detail.

Key Features of Interceptor

Interceptor is very widely used, thanks to its ease of administration and simple, once per month dosage. Here are a few key features of Interceptor that you need to know about.

  • Prevents 4 types of common worms – Interceptor destroys heartworm larvae, and can also destroy adult hookworms, roundworms and whipworms in dogs, ensuring that your pup is free of these parasites, and can live a healthy, happy life. All of these parasites can be commonly transmitted by mosquitoes, so it’s critical to protect your dog with a medication like Interceptor.
  • Can be used on dogs 4 weeks old, 2 lbs in weight – Unlike Interceptor Plus, Interceptor can be used on dogs as young as 4 weeks of age, so it’s a great option if your puppy is already going outside, and you are afraid of it becoming infested with heartworms, roundworms or any other parasite. You can start treating your puppy early, and make sure that it is completely safe.
  • Safe for use with pregnant or lactating females – Interceptor has been thoroughly tested for its safety when used on pregnant and lactating females. If you have a pregnant dog or a lactating dog, it’s one of the most highly-recommended anti-parasite medications.
  • Once per month treatment – Interceptor only has to be delivered to your dog once per month. For maximum effectiveness, you must treat your dog once per month for 6 months or more. This allows the drug to continue building up in your dog’s body, guaranteeing its safety from heartworms, hookworms and other such parasites.
  • Usable on dogs and cats – Interceptor can also be used to prevent heartworms and other parasites in cats, though at a smaller dosage than is typically recommended for most dogs. We do not recommend using a dosage of Interceptor meant for dogs to treat cats – you should obtain a separate prescription for an Interceptor product that is intended specifically for the needs of felines.

With its simple, delicious formulation, strong anti-parasitic effects, and once per month dosage, Interceptor is a convenient way to make sure your dog is completely protected from the most common worms and parasites.

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Key Features of Interceptor Plus

Want to learn more about Interceptor Plus, and if it’s right for you and your dog? Let’s take a more in-depth look at this pet medication now.

  • Prevents 5 types of common worms – Interceptor Plus fights back against heartworms (D. immitis), as well as hookworms (A. caninum), roundworm (T. canis, T. leonina) and whipworm (T. vulpis) as well as tapeworms. This means that it will provide protection against intestinal parasites as well as heartworms, and keep your dog safe and healthy.
  • Destroys 4 types of tapeworms – Praziquantel is the primary active ingredient in Interceptor Plus which destroys tapeworms, and it can eliminate all four of the most common types of tapeworm, including T. pisiformis, E. multilocularis, E. granulosus and D. caninum. This full-spectrum protection will help ensure the health and safety of your pup from all common tapeworms.
  • 100% effective against tapeworms –  Not only does Interceptor Plus provide your dog with full-spectrum tapeworm protection, but it also has been demonstrated as 100% effective against all common types of tapeworm when administered properly in a laboratory setting. That means you can rest assured that your dog is getting the best possible protection.
  • Can be used on dogs 6 weeks old, 2 lbs in weight – Interceptor Plus must be started slightly later, compared to Interceptor, so you’ll have to wait until your puppy is 6 weeks old. We recommend treating your dog as soon as possible, as you will have to administer up to 6 doses of medication over 6 months to get complete protection from heartworms and other parasites.
  • Once per month treatment – Interceptor Plus is a once-per-month, chicken-flavored chew which is delicious and easily ingested by all dogs. You can give it to your dog like a treat, or mix it in with your dog’s food. It’s important to administer Interceptor Plus to your dog on a regular basis.

Interceptor Plus is one of the best all-around anti-parasite medications for dogs, thanks to its full-spectrum protection and simple, once per month administration. Because it also can be used to fight against tapeworm, it’s also a great value compared to Interceptor.

What is Better For Dogs, Interceptor Or Interceptor Plus?

Both drugs have very similar side effects. They are very rare, but they can include:

  • Vomiting
  • Diarrhea
  • Depression and lethargy
  • Anorexia (loss of appetite)
  • Excess salivation
  • Ataxia (nervous system interference)
  • Convulsions
  • Muscle weakness

In some rare cases, these medications may also cause issues with dogs who have neurological difficulties. We recommend consulting with your veterinarian before you give your dog any kind of medication, to ensure its safety.

Both medications are just as safe, but there are a few exceptions. As mentioned, Interceptor has been tested for safety on dogs as young as 4 weeks old, and on pregnant and lactating dogs. Interceptor Plus can only be used on dogs that are 6 weeks of age or older.

If you have a young or pregnant dog, Interceptor is likely a safer choice. Again, though, you should consult your vet for their recommendation.

What’s Cheaper, Interceptor Or Interceptor Plus?

The price of both medications is identical. While you may find some slightly different prices, depending on the store at which you’re shopping, we found that Interceptor and Interceptor Plus were priced at the exact same price point on and a few other websites.

This means that, while Interceptor and Interceptor Plus are the same price, Interceptor Plus is actually a better deal. Why? Because unlike Interceptor, it treats tapeworm. That means Interceptor Plus gives you more protection for the same amount of money – making it an overall better value, and the cheaper pick between the two medications.

In addition, you can occasionally find manufacturer rebates for Interceptor Plus, while these are a bit more rare for Interceptor. This makes sense – since Interceptor Plus is a newer medication, the manufacturer may be trying to encourage customers to switch.

What Is Easier To Find, Interceptor Or Interceptor Plus?

This is a tie. Both Interceptor and Interceptor Plus are available at pretty much all major pet stores, including As long as you have a prescription for the medication, it’s extremely easy to find. You won’t have any issues with availability when it comes to Interceptor and Interceptor Plus.

If you’re not sure where you should shop for Interceptor or Interceptor Plus, you can always ask your veterinarian for a recommendation after you get a prescription for your dog. If you still can’t find either medicine locally, we recommend shopping online.

As long as you have a valid prescription for your pet, you can get Interceptor and Interceptor Plus delivered right to your door from a website like, and you may even get a better price compared to a local pet store. Explore your options, and you’re sure to make the right decision.

Which Is Better For Heartworms, Roundworms, Whipworms And Hookworms? Interceptor Or Interceptor Plus?

Both Interceptor and Interceptor Plus use the same active ingredient, milbemycin oxime, to fight back against infestations from these common parasites. It can destroy the larvae of heartworms and kill adult roundworms, whipworms and hookworms. There is no difference in efficacy between each medication, so this category is a tie.

It’s important to note, though, that you must inoculate your dog regularly with either Interceptor or Interceptor Plus for 6 months in order to be completely protected against heartworms.

In laboratory trials, 100% effectiveness against heartworm larvae was obtained after the drug had been administered for six months – but this was not the case after only 1-2 doses of the medication. Make sure you administer the drug consistently to your dog, to ensure that it enjoys total protection against heartworms.

Which Is Better For Tapeworms? Interceptor Or Interceptor Plus?

Interceptor Plus wins this category, hands down – because Interceptor does not have any anti-tapeworm effects. Interceptor Plus contains praziquantel, which has been used to eliminate tapeworms for more than 3 decades. It can destroy all of the 4 most common types of tapeworm with 100% effectiveness, keeping your dog’s digestion safe and ensuring that it can live a happy, healthy life.

Interceptor, on the other hand, does not contain praziquantel, so it will have no effect against tapeworms. If you are concerned about tapeworms in your dog, you will need to administer a separate anti-tapeworm medication for your dog, should you choose to use Interceptor instead of Interceptor Plus.

What’s Easier To Apply? Interceptor Or Interceptor Plus?

Interceptor Plus wins this category. Both Interceptor and Interceptor Plus use a chewable, tablet-based formula that is delicious and easy for your dog to eat.

However, Interceptor has an overall acceptability rate of about 94%, with a beef-based flavor. Interceptor Plus, with a naturally-flavored chicken formulation, had an acceptability rate of 96.6%.

Chances are that your dog will be happy to eat either medication, but because Interceptor Plus had a higher overall acceptability rate in laboratory studies, it wins this category.

If your dog refuses to eat both Interceptor or Interceptor Plus, we do not recommend hiding it in its food – it may fail to eat the entire thing, which could put your dog at risk. The best option is to crush the pill and mix it with another food that your dog likes, such as peanut butter or gravy. Then, you should feed the mixture to your dog directly. This will ensure that your dog receives the proper dose of medicine, and that it is fully protected from parasites such as heartworm, hookworm, whipworm and more.

Overall Winner Between Interceptor And Interceptor Plus

Overall, we would pick Interceptor Plus as the winner. It’s the same price as Interceptor and offers more protection – including defense against tapeworms. Because of this, there is no real reason to choose Interceptor. It’s effective against heartworms and other parasites – but it offers worse performance for the same price.

If you use Interceptor, you’ll need to buy a separate anti-tapeworm medication for your dog. You’ll also have to administer each drug separately, which can be a bit more inconvenient, compared to giving your dog a single Interceptor Plus pill per month.

Basically, there is no reason to not use Interceptor Plus – with only two exceptions. First, Interceptor Plus has not been tested on lactating and breeding female dogs, so Interceptor may be preferable if your dog is pregnant or lactating, and you are concerned about adverse effects from Interceptor Plus.

The other exception is if you have a puppy who is 4 weeks of age. You can start giving your dog Interceptor at 4 weeks, while Interceptor Plus requires you to wait until 6 weeks of age. If you are concerned about your dog’s susceptibility to parasites and wish to start treating it as soon as possible, Interceptor may be the best choice.

As always, we always recommend that you consult with your veterinarian if you have any concerns or are not sure about which medicine is right for your dog. Your vet will be able to prescribe the proper medication for your pup, and ensure its safety from parasites like heartworms, tapeworms and more.

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FAQs About Interceptor And Interceptor Plus – Answering Your Questions

Got more questions about Interceptor, Interceptor Plus, and anti-parasite medications in general? In this guide, we’ve put together a list of some of the most frequently-asked questions about the subject. Read on, and you can ensure that you have the knowledge you need to protect your dog.

  • How do anti-parasite medications work? – While there are a lot of different anti-parasite medications available, including Interceptor and Interceptor Plus, they all use the same basic method of action. The active ingredient is built to interfere with the proper functioning of the nervous system of worms, destroying adults and preventing larvae from hatching. Then, the parasites are naturally eliminated from your dog’s body.
  • How can I protect myself from parasites? – Some parasites, like hookworms, that affect dogs can also be transmitted to humans. The best way to protect yourself is to take your dog to the vet for a regular checkup to check for infestations, and ensure that they get anti-parasite medication like Interceptor or Interceptor Plus to prevent infestations.
    You should also make sure to clean up dog waste from your yard regularly, and keep your pets out of areas like sandboxes where children may play. Wash your hands thoroughly after handling pet waste. You should also always wear shoes and gloves when gardening or landscaping in an environment that has contained pet waste, as some parasites can live for months under the soil.
  • Are all dogs at risk of heartworms, hookworms and other parasites? – Yes. Mosquitoes often carry larvae for these parasites, and can infect your dog with even a single bite. Even if your dog mostly stays inside or lives in the city, you could be at risk of a parasitic infestation if you do not treat your dog with a medication like Interceptor or Interceptor Plus.
  • Will Interceptor or Interceptor Plus help control fleas and ticks? – No. Neither of these medications incorporate any active ingredients that help repel, control or kill ticks and fleas. Your dog will need to take a separate medication for this purpose.
    However, neither Interceptor or Interceptor Plus have any contraindications for common flea and pest protection medications like NexGard – so they are safe to use alongside these medicines. Again, we recommend consulting with your veterinarian if you need an anti-flea and anti-tick medication.
  • Will Interceptor or Interceptor Plus destroy existing parasites? – Yes, except for heartworms. Interceptor can destroy adult hookworms, roundworms, and whipworms. Interceptor Plus destroys all of those parasites, as well as adult tapeworm. Both medicines also help control and destroy larvae, preventing further re-infestation.
    However, neither Interceptor or Interceptor Plus will be able to destroy existing adult heartworms. Both medications are intended to stop the development of heartworm larvae and prevent them from gestating and hatching. If your dog already has heartworms, these medications will not be effective at removing them.
    Instead, you will need to seek help from your veterinarian. Your dog will be put on a regimen of specialized medicine, such as an intramuscular immiticide treatment, which will destroy the adult heartworms. Once these heartworms have been destroyed, medicine like Interceptor and Interceptor Plus will prevent any more larvae from hatching.
  • What if I forget to give my dog Interceptor or Interceptor Plus? – For ideal results, you should make sure to administer medicine to your dog every single month, at the same time. This is the only way to guarantee maximum effectiveness of Interceptor or Interceptor Plus.
    However, accidents happen. If you do forget to give your dog its medication and you are a few days late, just make sure that you give it the medicine as soon as you can. We recommend setting up monthly, electronic reminders on your phone or computer, or using a calendar to keep track of dosage. This is the best way to make sure that you never miss a day when you need to give your dog its medication.

Hopefully, these above questions and answers have helped you learn more about Interceptor and Interceptor Plus. Thanks for reading, and remember that if you have any other questions or concerns, you can always ask your veterinarian during your dog’s next appointment!


We hope that this article has been useful and informative, and aided you in understanding the differences between Interceptor and Interceptor Plus. While both medications are quite similar, there are some important distinctions that may make one or the other a better choice for you and your dog.

You’ll need a prescription for both of these drugs, too – so if you have any other questions or concerns, you can ask your vet during your dog’s next check-up. With their input and the information that you’ve learned in this article, you’re sure to be able to get the right medicine for your dog. Shop now, and make sure you protect your dog from parasites!

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