Interceptor Plus vs. Heartgard Plus: Key Differences

When it comes to protecting your dog from parasites, choosing the best monthly preventative can feel like a puzzle. Interceptor Plus and Heartgard Plus are two of the most common options recommended by veterinarians, and while they both offer essential protection against heartworms and intestinal parasites, they differ in a few key areas, like scope, ingredients, and the type of protection they provide. 

Both Interceptor Plus and Heartgard Plus are monthly chewable preventatives that protect dogs from heartworms and certain intestinal parasites. They come in tasty, treat-like forms (so giving them isn’t usually a battle) and are available by prescription.

Heartgard Plus contains ivermectin and pyrantel. It helps prevent heartworm disease and treats/controls roundworms and hookworms. It’s a solid, long-standing option that a lot of vets trust.

Interceptor Plus contains milbemycin oxime, which targets heartworms, roundworms, hookworms, and whipworms, and praziquantel, which specifically treats tapeworms, providing a broader spectrum of protection. 

Both medications are given once every 30 days to keep your dog protected.



It’s a good idea to set a recurring reminder (or mark your calendar) so you don’t accidentally miss a dose. Consistency is key when it comes to preventing heartworm disease, which can be very serious (and expensive) to treat if it develops.

Here’s where the biggest difference comes in.

Both options cover:

• Heartworms
• Roundworms
• Hookworms
• 
  

But Interceptor Plus also protects against:

• Whipworms
• Tapeworms



That extra coverage can be helpful depending on where you live or what kind of environments your dog spends time in. For example, dogs who roam wooded areas, have access to wild animal droppings, or do a lot of outdoor exploring may benefit from the broader protection that Interceptor Plus provides.

Both medications are generally safe when used as directed. But, as with any medication, it’s good to know what to watch for.



• Heartgard Plus has been around for a long time and is safe for most breeds. If your dog is a collie or has a sensitivity to ivermectin, your vet may just want to double-check the dosage or consider an alternative.

• Interceptor Plus is also considered safe, though dogs with a history of seizures or certain neurological conditions should be monitored, as milbemycin can occasionally trigger reactions in sensitive pets.

In both cases, mild side effects like soft stools, upset stomach, or lethargy are possible but uncommon. If something feels off, always give your vet a call.

There’s no one-size-fits-all answer, but knowing the differences helps you make a more informed choice.



• If you’re looking for basic, reliable heartworm protection with coverage for common worms, Heartgard Plus is a great option.

• If your dog spends time outdoors, has access to areas where parasites may be more common, or you simply want that extra layer of protection, Interceptor Plus might be worth considering.

At the end of the day, the right medication is the one that fits your dog’s needs and your peace of mind. And with both medications being available through PetPawsRx, we make it easy to order and refill your pet’s prescription online, often at a lower cost than your vet’s office.

Want more pet health tips and helpful info like this? Sign up and Save! Subscribe to our Newsletter today, and stay in the know and receive exclusive deals.