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Interceptor Plus for Dogs: Internal Parasite Protection

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Medication details

  • Medication type: Antiparasitic
  • Form: Soft chew
  • Prescription required? Yes
  • FDA approved? Yes
  • Brand names: Interceptor Plus
  • Available dosages: 2-8 pounds (2.3 mg milbemycin oxime, 22.8 mg praziquantel), 8.1-25 pounds (5.75 mg milbemycin oxime, 57 mg praziquantel), 25.1-50 pounds (11.5 mg milbemycin oxime, 114 mg praziquantel), and 50.1-100 pounds (23 mg milbemycin oxime, 228 mg praziquantel)
  • Expiration range: See package insert for expiration date.

Internal worms can make our pets sick, and some are infectious to people, too. They can cause uncomfortable symptoms like diarrhea and vomiting in otherwise healthy dogs. Young puppies infected with intestinal worms like hookworms and roundworms can quickly develop severe anemia, which can be fatal. Heartworms, which live in the blood vessels of the lungs and heart, can seriously damage your dog’s cardiovascular system and be fatal if left untreated. 

The bad news is that worms are more common than you realize. With changing weather patterns and increased mobility of pets and people, they are growing in prevalence. 

The good news is that you can protect your dog against internal parasites with a product like Interceptor Plus. 

What Is Interceptor Plus for Dogs?

Interceptor Plus packaging

Interceptor Plus is an oral medication that protects against five types of worms in dogs: heartworms, hookworms, roundworms, whipworms, and tapeworms. The active ingredients in this tasty soft chew for dogs are milbemycin oxide and praziquantel. Originally produced by Novartis Animal Health, Interceptor had been around for more than 25 years as a heartworm prevention medication. Interceptor was added to Elanco Animal Health’s portfolio when the company acquired Novartis in 2015, and Interceptor Plus was approved for use in dogs by the FDA in 2017. It is available in all parts of the United States and via online pharmacies by prescription only. 

The difference between Interceptor vs. Interceptor Plus is that Interceptor only contains milbemycin oxide and Interceptor Plus contains milbemycin oxide and praziquantel. Both protect dogs against heartworm disease, adult hookworm, roundworm, and whipworm infections. The main difference between these two medications is that Interceptor Plus also protects against tapeworm infections. 

What Is Interceptor Plus Used for in Dogs?

Interceptor Plus is prescribed to prevent heartworm disease and treat and control roundworm, hookworm, whipworm, and tapeworm infections in dogs. Heartworms are internal parasites that are transmitted by mosquitoes. Heartworms live in the large artery that exits the heart, and cause inflammation and damage to the heart and lungs. Roundworms, hookworms, whipworms, and tapeworms are internal parasites that live in the intestines and cause diarrhea and weight loss. Some intestinal parasites in dogs are also contagious to people, especially children. 

Credelio, a highly effective oral tick and flea control medication, can be paired with Interceptor Plus to provide broad-spectrum parasite protection for dogs. Your veterinarian may recommend using both of these products together.

How Does Interceptor Plus Work?

Milbemycin oxide, an active ingredient in Interceptor Plus, kills roundworms, hookworms, whipworms, and young heartworms by interfering with the central nervous system of the parasites, causing paralysis and death. 

Milbemycin is not effective against the adult form of heartworms, so it is important to test your dog for adult heartworms before administering Interceptor Plus. This can be done with a simple blood test at your local veterinary clinic.

Praziquantel, the other active ingredient in Interceptor Plus, works by expelling tapeworms from the intestines and preventing newly hatched insect larvae from reaching adulthood or reproducing. 

How to Give Interceptor Plus to Dogs

To control worms in dogs, Interceptor Plus should be given once a month, preferably on the same day each month. Most dogs will readily eat Interceptor Plus, as it looks and smells like a chewy treat. 

Interceptor Plus is designed to be chewed before it is swallowed. If your dog swallows treats whole, break the chew into pieces before feeding it to your dog. If your dog refuses to eat it, you can try offering the chew wrapped in a pill pocket, stuffed in a piece of hot dog, or covered in a small amount of peanut butter, canned food, or spray cheese. 

Interceptor Plus for Dogs Reviews

Interceptor has been used within the veterinary community for over 25 years for heartworm disease prevention and intestinal parasite protection in dogs with great success and a high level of safety. Praziquantel, the additional active ingredient in Interceptor Plus, has also been used to treat tapeworms in dogs for many years. I personally have prescribed Interceptor Plus to thousands of patients and used Interceptor Plus in my own pets without any problems and excellent control of internal parasites.

Internal parasites can be found in any dog—even dogs that rarely go outside. Interceptor Plus is recommended for all dogs (6 weeks or older and 2 pounds or greater).

Many pet parents ask how Interceptor Plus for dogs compares to other oral parasite control products like Heartgard and Simparica Trio. Here is a comparison chart:

Interceptor PlusHeartgard PlusSimparica Trio
Active ingredientsMilbemycin oxime and praziquantelIvermectin and pyrantel pamoateSarolaner, moxidectin, and pyrantel
FormChicken-flavored soft chewBeef-flavored soft chewBeef-flavored chewable tablet
Dose1 chew/month1 chew/month1 tablet/month
Prevents heartworm diseaseYesYesYes
Treats and controls intestinal wormsRoundworms, hookworms, whipworms, and tapeworms Hookworms and roundwormsHookworms and roundworms
Kills ticks and fleasNoNoYes

Interceptor Plus Side Effects

In general, Interceptor Plus is considered to be very safe and tolerated by the majority of dogs. The following rare adverse reactions have been reported in dogs after administration:

  • Vomiting
  • Diarrhea
  • Lethargy
  • Weight loss
  • Salivation
  • Convulsions
  • Incoordinations

If you are concerned about giving Interceptor Plus to your dog, please talk to your veterinarian.

Interceptor Plus Dosage for Dogs

Interceptor Plus chews

Dosage of Interceptor Plus varies depending on the weight of your dog. There are four dosages available for different weight ranges in dogs: 2-8 pounds, 8.1-25 pounds, 25.1-50 pounds, and 50.1-100 pounds. For maximum efficacy, talk to your veterinarian about the right dose for your dog. 

Puppies older than 6 weeks of age and weighing more than 2 pounds can safely take Interceptor Plus.

Interceptor Plus stays in your dog’s system for about 24 hours, killing and removing any heartworm larvae and intestinal worms. If your dog is accidently infected in the next month, the next dose of Interceptor Plus will kill all larvae before they have a chance to grow or reproduce. 

Cost of Interceptor Plus for Dogs

Interceptor Plus costs approximately $80-$100 per year, depending on the size of your dog (it is more expensive for larger dogs).

Interceptor Plus Storage Instructions

Interceptor Plus can be safely stored at room temperature out of reach of dogs.

Where to Buy Interceptor Plus

Interested in purchasing Interceptor Plus for dogs? You can check to see if it is available on your veterinarian’s online pharmacy.