Heartgard Products

"Heartgard vs. Interceptor...

So what is the difference between Heartgard and Interceptor? Millions of pet owners are dying to know.

With all the knockoffs out there patterning themselves after the official Heartgard product, it’s hard to tell which ones you can trust and which ones you should steer clear of. Interceptor is only one of the many that are currently giving Heartgard competition.

Pet owners weigh in on: Heartgard dosage vs. Interceptor dosage

Heartgard Plus:

  • The major variation (aside from active ingredients) is that Heartgard is the more all-inclusive of the two.
  • Heartgard Plus (Pyrantel, Ivermectin) Chewable takes care of hookworms, heartworms, and roundworms.
  • If you change from Heartgard to Interceptor (your dog may even have been on it its entire life thus far) the dog will need to get a blood test done. If your pet already has heartworms, Interceptor can hurt them.
  • Heartgard can be purchased without a prescription.
  • If whipworms aren’t a problem in your area, why would you subject your dog to another chemical that it doesn’t need by giving them Interceptor? Many pet owners these days are getting away from exposing their pets to chemicals and vaccines that aren’t really needed; depending on the circumstances under which the pet exists (i.e. Never goes outside, is never exposed to other animals, is subjected to freezing temperatures four or more months out of the year, etc.).
  • Interceptor can only be purchased with a prescription from a veterinarian (veterinarians will charge a substantial fee for a records review, in order to write a prescription for your dog.

Interceptor dosage:

  • Heartgard can cause seizures in dogs that are already predisposed to them.
  • Sentinel and Interceptor are the only heartworm meds that also get rid of whipworms.
  • Heartgard has Ivermectin which cannot be used on some collies.

What’s all the fuss?

More than 1 dog owner has said that they ‘pay through the nose’ for the necessary Interceptor dosage for their dog. This is a bit surprising considering that there have also been numerous reports of Interceptor being cheaper than Heartgard. So which is it? And on the topic of Ivermectin, it used to be a patented drug and is the active ingredient in Heartgard.

Its patent expired so more animal pharmaceutical companies changed over to it. It is now the major ingredient in almost all heartworm medications. While it’s true that there is a minor “sub group” of collies exhibiting a reaction to it, a test is now available to see if your collie is indeed part of that sub group.

Ivermectin was for years utilized in the treatment of livestock (like a 1500 lb cow). Some dog owners tried working it down to a suitable dose for a 60 lb dog. It’s no small wonder the drug got a bad reputation after someone messing around until they discovered just the right dosage.

Call me old school, but I prefer a brand that I’ve known and trusted for years. Until that brand is proven to be bad for my dog in particular, I will more likely than not stick with it.


Disclaimer: We're in no way affiliated with the Merial Health Company, whom Heartgard® is a registered trademark of - we just love and support the product.