Heartgard Plus Chewable Tablets for Dogs, 26-50 lbs, 6 treatments

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Heartgard Plus is a heartworm preventative that kills heartworms and helps to control and treat hookworms. Given monthly, it comes in a chewable tablet that you can feed to your pal as a tasty, beef-flavored treat. Head back to the dog park, reassured that your dog is protected from nasty parasites.


To prevent heartworm disease by eliminating the tissue stage of heartworm larvae (Dirofilaria immitis) for one month (30 days) after infection.

Possible Side Effects

Please contact your veterinarian if your pet is suffering from the following: Depression/lethargy, vomiting, anorexia, diarrhea, mydriasis, ataxia, staggering, convulsions, and hypersalivation.

Drug & Food Interactions

Heartgard Plus has shown a wide margin of safety at the recommended dose level, including pregnant or breeding females, male dogs and puppies aged six or more weeks. In clinical trials, many commonly used flea collars, dips, shampoos, anthelmintics (anti-parasitic drugs), antibiotics, vaccines and steroid preparations have been administered with this medication in a heartworm disease preventive program.


All pets should be tested for existing heartworm infection before starting treatment with this medication, which is not effective against adult heartworm. Keep this and all drugs out of the reach of children. In case of ingestion by humans, clients should be advised to contact a physician immediately. Physicians may contact a Poison Control Center for advice concerning cases of ingestion by humans.

  1. Prescribing Information

See all items by Heartgard

  • Item Number
  • Dosage Measure

    Use according to your veterinarian's instructions.

  • Common Brand Name(s)

    Heartgard Plus, Tri-Heart Plus

  • For Use With

    Dogs - 6 weeks or older

  • Generic Name

    Ivermectin, Pyrantel Pamoate

  • Brand

    Merial, Boehringer Ingelheim

  • Breed Size

    Medium Breeds

  • Product Form

    Chewable Tablet

  • Health Condition

    Heartworms, Roundworms, Hookworms

  • Drug Type




Recommended Dosage

This medication should be administered orally at monthly intervals. Consult your veterinarian for proper dosing instructions.

Storage Instructions

Store between 68° - 77°F. Protect product from light.

HEARTGARD Chewables should be administered orally at monthly intervals at the recommended minimum dose level of 6.0 mcg of ivermectin per kilogram (2.72 mcg/lb) of body weight. The recommended dosage schedule for prevention of canine heartworm disease is as follows:

Dog Weight HEARTGARD for Dog per Month Ivermectin content Color Coding on Foil Backing and Carton
Up to 25 lbs 1 chewable 68 mcg Blue
26 to 50 lbs 1 chewable 136 mcg Green
51 to 100 lbs 1 chewable 272 mcg Brown

Give dogs over 100 lbs the appropriate combination of these chewables. HEARTGARD Chewables are recommended for use in dogs 6 weeks of age and older.


What is heartworm disease?

Heartworm disease in dogs (dirofilariasis) is a serious and potentially fatal disease. Heartworms spend their adult lives in the pulmonary arteries. The adult worms can cause lasting damage to the heart, lungs and arteries.

How do dogs get heartworms?

Heartworms are transmitted from one dog to another by mosquitoes, which pick up tiny immature heartworms, called microfilariae, when they bite an infected dog. Larvae develop and are then transmitted to another dog when that dog is bitten by the infected mosquito.

Where are dogs at risk for heartworm infection?

All dogs are at risk for heartworm disease, no matter where they live—heartworms don't discriminate based on geography. In the past, heartworm disease in the United States was primarily limited to the South and Southeast regions. However, it is now found in all 50 states, in Canada, and is spreading to new areas each year. The American Heartworm Society notes that uncared-for dogs and certain wildlife can be carriers of heartworms. Mosquitoes blown great distances by the wind and the transportation of infected pets to different geographic locations can all contribute to the spread of heartworm disease.

What are the signs of heartworm infection?

Signs of heartworm disease can be subtle and difficult to detect until its later stages. As the disease progresses, signs begin to appear. Contact your veterinarian immediately if you notice coughing, difficulty breathing, sluggishness and less energy for exercise in your dog. Adult heartworms cause serious harm to your dog's heart, lungs and certain internal organs. Left untreated, heartworm disease can result in loss of consciousness and death.

How are dogs tested for heartworm infection?

The most common method for heartworm testing is for a veterinarian to collect a small blood sample from a dog and evaluate the sample using a specialized test kit to detect the presence of adult heartworms.

How can heartworm disease in dogs be prevented?

Pet owners can use Heartgard Plus (ivermectin/pyrantel), the #1 veterinarian-recommended preventive on the market to help prevent heartworm disease. Heartgard Plus kills tissue larval stages of heartworms and helps prevent them from developing into adults and causing heartworm disease. In an unprotected dog, heartworm larvae mature into adults and ultimately migrate to the arteries of the lungs.

How long do I have to give my dog Heartgard Plus?

Monthly use of Heartgard Plus is essential because it cannot be determined with certainty when the threat of mosquitoes has passed. Talk to your veterinarian for dose and regimen recommendations.

Can heartworm disease be treated?

Although it is possible to treat heartworm disease if a dog becomes infected, it is difficult, expensive and risky, particularly in dogs that have begun to exhibit clinical signs of infection.

What if my dog becomes infected with heartworms?

There are treatment options available to kill adult heartworms in dogs that have become infected. Treating dogs with heartworm disease starts with a thorough physical examination by the veterinarian. The veterinarian will then discuss treatment options with you. Typically, the dog is hospitalized during the treatment period. Because there is a risk of blood clots or worm debris blocking blood vessels from adult heartworm treatment, the dog must then remain quiet in close confinement for another 4 to 6 weeks after treatment. A second round of treatment may be required for some dogs. The veterinarian may also give your dog a treatment to rid it of the immature larvae that are circulating through the blood stream.

Is Heartgard Plus safe to use in any breed of dog?

Heartgard Plus is safe and effective in any breed of dog when used as directed.

Can my dog "get" heartworm disease directly from an infected dog?

No, the way dogs become infected is via a bite from a mosquito that is carrying heartworm larvae.

Are nursing puppies immune to heartworm disease if the mother is receiving Heartgard Plus?

No. Puppies that are nursing may become infected. Heartgard Plus can be used in puppies as young as 6 weeks of age—and puppies benefit from the ability of Heartgard Plus to treat and control roundworms and hookworms.

Customer Reviews
25 Reviews 25 Reviews 5 out of 5 Stars

96% Recommend

96% of reviewersrecommend this product

5 / 5

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  • As far as I know it works

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    I have been using this on my dog for 5 years as far as I know it works (she hasn't had worms). I am not sure if this is luck or product working. My only issue is the beef in it makes her have allergies but it is the only medication she can handle on her stomach. This is good for dogs with weak stomachs. She is 42 pounds and I give her the 26-50.

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  • Perfect for dogs that can spit out a pill

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    Been using this product for several years. My last pug could spit out a pill no matter what you did-and this product solved the problem. Fortunately my current pug will eat anything remotely resembling food.

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  • Awesome as Always

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    This is the only heartworm preventive that my dog will take and I have used this brand for years. Chewy.com's price was $10 less than the online pharmacy I usually use. Very happy overall.

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  • Mmmmm mmmmm good

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    My three girls are so happy to find chewy.com! Saves us bunches of money! Even more happy that chewy has pharmacy service, now we save even more money!

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  • Excellent!

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    This heartworm preventative works well for Barky, she loves the flavor and I have no problems with her eating them. The price is also excellent.

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  • My Vet Stopped Carrying This Product!

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    I tried switching my dog to the new heart worm preventative that the vet’s office dispensed but he would not take them. He just loves his Heartgard and Chewy provided really prompt delivery.

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  • So easy to order and receive!

    By on

    So so easy! I told chewy what heart worm Pills I needed and the name of my vet! Two days later they were at my house! Amazing! I love Chewy!

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  • Heartgard Plus Chewable Tablets for Dogs

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    Heartgard Plus Chewable Tablets for dogs is a must for our dogs in order to prevent heartworm. Both our dogs chew them up with no problem.

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  • My Dog Thinks This Medicine is a Treat!

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    My Boykin Spaniel will fight me on pills, even in a pill pocket. But he will eat his heart guard like it’s a treat. Grateful to them for making them seemingly taste great!

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  • Tasty treat

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    My dog hates the generic pills. She spits them out even when they're covered with peanut butter. These, she thinks they're a treat.

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