Chewable tablets containing ivermectin and pyrantel. For use in dogs to prevent canine heartworm disease by eliminating the tissue stage of heartworm larvae (Dirofilaria immitis) for a month after infection and for the treatment and control of ascarids (Toxocara canis, Toxascaris leonina) and hookworms (Ancylostoma caninum, Uncinaria stenocephala, Ancylostoma braziliense).


Tri-Heart Plus (ivermectin/pyrantel) is a proven, cost-effective and easy-to-administer chewable tablet that helps keep your dog free of heartworm and other dangerous parasites.1

Dogs of any age, even older dogs, can become infected with heartworms, roundworms or hookworms.

Tri-Heart Plus chewable tablets contain a proven combination of ingredients to protect your dog and ensure your complete peace of mind. Ask your veterinarian about Tri-Heart Plus today.


How To Administer

Give your dog one beef-flavored chewable Tri-Heart Plus tablet on the same day each month. Dogs that are on a preventive medicine should also be tested routinely to ensure protection, especially if a dose has been missed or forgotten.

Register to receive free monthly email reminders when it’s time to give your dog his next dose of Tri-Heart Plus. Place free Reminder Stickers onto your calendar (you will find these inside packages of Tri-Heart Plus).

Product Information

Brief Summary

Please consult the full package insert for more information.


Tri-Heart Plus chewable tablets are indicated for use in prevention of canine heartworm caused by Dirofilaria immitis and for the treatment and control of ascarids (Toxocara canis, Toxascaris leonina) and hookworms (Ancylostoma caninum, Uncinaria stenocephala, Ancylostoma braziliense) in dogs and in puppies six weeks of age.

Adverse Reactions

The following adverse reactions have been reported following the use of ivermectin at the recommended dose: depression/lethargy, vomiting, anorexia, diarrhea, mydriasis, ataxia, staggering, convulsions and hypersalivation.


Federal (U.S.A.) law restricts this drug to use by or on the order of a licensed veterinarian.


Tri-Heart Plus chewable tablets are available in three dosage strengths for dogs of different weights. Each strength comes in convenient packs of 6 chewable tablets.
Store at controlled room temperature of 59-86° F (15-30° C). Protect product from light.

Fair Balance

All dogs should be tested for heartworm infection before starting a preventive program. In a small percentage of ivermectin/pyrantel treated dogs, digestive and neurological side effects may occur.

For additional information, please see the product label.


1. Freedom of Information Summary, ANADA 200-338. Approved August 13, 2003


Tri-Heart Plus FAQs

These FAQs should answer most of your questions, but if there is something more you want to know, you can always contact us for more information.

Q. Our dog’s Tri-Heart Plus flavored chewable tablets expired last month. Is it still okay to give her Tri-Heart Plus tablets after their expiration date?

A. Medications, including Tri-Heart Plus, should never be administered after the expiration date. Studies have shown that Tri-Heart Plus will maintain its desired effectiveness when administered prior to the expiration date, when stored as recommended on the label.

Q. My dog weighs less than 10 lbs. Should I give him the whole tablet even though it says for dogs up to 25 lbs?

A. Yes. The entire tablet should be administered as a single dose once each month. The smallest-sized Tri-Heart Plus tablet, in the blue-colored packaging, is labeled for dogs weighing 25 lbs or less. These tablets are scored to make it easier to break the tablet apart and have the small dog take the complete tablet but in smaller pieces at a time. Regardless of whether the tablet is broken apart or given whole, the entire tablet should be given as a single dose.

Q. Is it okay to give my pregnant dog Tri-Heart Plus tablets? What about after she has given birth and is breastfeeding the puppies?

A. Ivermectin/pyrantel, the active ingredients in Tri-Heart Plus, have a wide margin of safety at the recommended dose level in dogs, including pregnant females, breeding males and females, and puppies 6 weeks old or more according to the package insert.

Q. I accidentally gave my dog his Tri-Heart Plus tablet after my husband had already given one to him. Will he be okay?

A. Contact your veterinarian immediately if accidental overdose occurs. To reduce the risk of accidental overdose in situations where more than one person may administer Tri-Heart Plus, we suggest ticking off the date on a specially marked calendar or making some other note to indicate that the dose has been given. Make a habit of checking with the other pet caregivers in your household before giving any medications to your pet.

Q. My dog is taking some other medications for another condition. Is it still safe to give her Tri-Heart Plus tablets?

A. In clinical trials, many commonly used flea collars, dips, shampoos, antihelmintics (deworming medications), antibiotics, vaccines, and steroid preparations have been administered with ivermectin/pyrantel in a heartworm disease preventive program. For questions on specific medications, please consult with your veterinarian.

Q. I forgot to give my dog his Tri-Heart Plus medication last month. Is he still protected? What should I do?

A. If the interval between doses exceeds 30 days, the efficacy of ivermectin can be reduced. Therefore, for optimal performance, the chewable tablet must be given once a month, on or about the same day of the month (Sign up for our email reminder service). If treatment is delayed, whether by a few days or many, please contact your veterinarian, as immediate treatment with Tri-Heart Plus chewable tablets and resumption of the recommended dosing regimen minimizes the opportunity for the development of adult heartworms.

Q. Where can I buy Tri-Heart Plus tablets?

A. Tri-Heart Plus flavored chewable tablets can be obtained by prescription only and are available from your veterinarian.

Q. Is Tri-Heart Plus safe for my dog?

A. Tri-Heart Plus flavored chewable tablets are an FDA-licensed product, indicating that they are safe and effective when used as recommended on the label. All dogs should be tested for existing heartworm infection before starting treatment with Tri-Heart Plus.

Q. How long will the Tri-Heart Plus tablets last once removed from the blister pack?

A. The blister package is designed to protect the tablets from exposure to air and light. Therefore a tablet should be administered at the time it is removed from the blister foil. Also if the blister or foil is not intact (for example the foil is peeled back or there’s a hole in it), the tablet should not be used.

Q. Can Tri-Heart Plus be used as a heartworm preventive in cats?

A. No. Tri-Heart Plus is not approved for use in cats.

Q. Do Tri-Heart Plus tablets contain wheat or rice gluten?

A. No.

Q. Can Tri-Heart Plus tablets be given to a dog that has heartworms or that is heartworm positive?

A. No. Tri-Heart Plus is labeled for use in dogs to prevent heartworm disease and not for the treatment of heartworm infections. The package insert contains a precautionary statement that ‘Infected dogs must be treated to remove adult heartworms and microfilariae before initiating a program with Tri-Heart Plus flavored chewable tablets.’

All dogs should be tested for heartworm infection before starting a preventive program. In a small percentage of ivermectin/pyrantel treated dogs, digestive and neurological side effects may occur.1

Q. Where can I find additional information about heartworms?

A. The American Heartworm Society (AHS) is an excellent source of information for both pet owners and veterinarians. Please see their Web site