Heartgard Chewables for Cats, up to 5 lbs (Red Box), slide 1 of 1

Heartgard Chewables for Cats, up to 5 lbs, 6 treatments (Red Box)

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Your furry friend must have a current heartworm test result on file with your veterinarian in order to be prescribed heartworm medication. Please visit your veterinarian to have this test performed annually to protect your four-legged friend. Heartgard is a heartworm preventative that kills feline heartworms and helps to control and treat hookworms. Given monthly, it comes in a chewable that you can feed to your pal as a tasty, beef-flavored treat. If your cat has a tendency to swallow her food or treats whole, you can break each tablet into small pieces for easier feeding.


To prevent heartworm disease by eliminating the tissue stage of heartworm larvae Dirofilaria immitis for a month (30 days) after infection and for removal and control of adult and immature hookworms Ancylostoma tubaeforme and A. braziliense.

Possible Side Effects

In the clinical studies involving more than 3000 doses of Heartgard for Cats, observations reported within 24 hours of treatment included vomition in ≤ 0.3% and diarrhea in ≤ 0.2% of the doses administered. There were no statistical differences between Heartgard for Cats and the product vehicle (control) for these observations.

Drug & Food Interactions

Talk to your veterinarian about any other drugs your pet is taking before starting this medication.


Heartgard (ivermectin) is well tolerated. All cats should be tested for heartworm infection before starting a preventive program. Following the use of Heartgard, digestive and neurological side effects have rarely been reported. Federal law restricts this drug to use by or on the order of a licensed veterinarian.

Dosage Chart

Color on BoxWeight RangeStrengthDosageProduct Page
RedUp to 5 lbs55 mcg IvermectinAdministered orally at monthly intervals✓-Click Here
Purple5-15 lbs165 mcg IvermectinAdministered orally at monthly intervals✓-Click Here
  1. Prescribing Information

See all items by Heartgard

  • Item Number
  • Generic Name
  • Common Brand Name(s)
    Heartgard, Ivomec
  • For Use With
    Cats - 6 weeks or older
  • Administration Form
  • Brand
    Merial, Boehringer Ingelheim
  • Breed Size
    Extra Small & Toy Breeds
  • Product Form
    Soft Chew
  • Strength
    55 mcg Ivermectin
  • Health Condition
    Heartworms, Hookworms
  • Drug Type

55 mcg Ivermectin.

Recommended Dosage

Consult your veterinarian for proper dosing instructions. For use in pets six weeks of age and older. Administer once a month. The initial dose must be given within a month after pet’s first exposure to mosquitoes. The final dose must be given within a month after the pet’s last exposure to mosquitoes.

Storage Instructions

Store at controlled room temperature of 68°F - 77°F (20°C - 25°C). Excursions between 59°F - 86°F (15°C - 30°C) are permitted.


What are the Key Benefits of Heartgard?

  • Beef-flavored chewable to be given monthly

  • Prevents heartworm from developing inside cats

  • Safeguards against further heartworm infection

  • Treats and controls hookworms

  • FDA approved

What is heartworm disease?

Heartworm disease in cats (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 cats get heartworms?

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

Where are cats at risk for heartworm infection?

All cats 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 cats 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 cat. Adult heartworms cause serious harm to your cat's heart, lungs and certain internal organs. Left untreated, heartworm disease can result in loss of consciousness and death.

How are cats tested for heartworm infection?

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

How can heartworm disease in cats be prevented?

Pet owners can use Heartgard (ivermectin) to help prevent heartworm disease. Heartgard kills tissue larval stages of heartworms and helps prevent them from developing into adults and causing heartworm disease. In an unprotected cat, heartworm larvae mature into adults and ultimately migrate to the arteries of the lungs.

How long do I have to give my cat Heartgard?

Monthly use of Heartgard 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 cat becomes infected, it is difficult, expensive and risky, particularly in cats that have begun to exhibit clinical signs of infection.

What if my cat becomes infected with heartworms?

There are treatment options available to kill adult heartworms in cats that have become infected. Treating cats with heartworm disease starts with a thorough physical examination by the veterinarian. The veterinarian will then discuss treatment options with you. Typically, the cat 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 cat 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 cats. The veterinarian may also give your cat a treatment to rid it of the immature larvae that are circulating through the blood stream.

Is Heartgard safe to use in any breed of cat?

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

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

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

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

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

What is the best number to call regarding any specific product questions?

For any specific product questions, please call Boehringer Ingelheim Animal Health’s customer service line number at 1-888-637-4251.

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