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Heartgard for Dogs & Puppies

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Heartworm Tablets for Dogs help prevent canine heartworm disease in dogs. Formulated for dogs with food allergies. Heartgard Tablets contain ivermectin, but are free of the food ingredient additives that may trigger an allergic reaction. Give monthly, as directed. Heartgard Tablets kill immature heartworms that have been introduced to the dogs within the last 30 days. Approved for puppies as young as 6 weeks, pregnant or breeding female dogs, and stud dogs.

Key Benefits

  • The veterinarian's #1 choice for heartworm disease prevention in dogs.
  • Used monthly as directed can help prevent heartworm infection in your dog – and can help your dog avoid the risk, stress, and long periods of confinement that go along with treatment for canine heartworm disease.
  • Convenient, easy-to-give tablet
  • No added beef - ideal for dogs with allergies to certain meats or additives
  • Available in three dosage strengths for dogs of different weights. Your veterinarian will select the dosage that's right for your dog.
  • Has a wide margin of safety for dogs of all breeds and sizes when used as directed. It is approved for puppies as young as 6 weeks, pregnant or breeding female dogs, and stud dogs.
  • HEARTGARD for dogs: Easy to Give. Protection to Live.


For use in dogs to prevent canine heartworm disease. HEARTGARD® prevents heartworm disease by eliminating the tissue stage of heartworm larvae (Dirofilaria immitis) for a month (30 days) after infection.


Active Ingredients:

Ivermectin (68 mcg)


Heartgard Tablets should be administered orally at monthly intervals at the recommended minimum dose level of 6 mcg of ivermectin per kilogram (2.72 mcg/lb) of body weight. (See Administration). The recommended dosage schedule for prevention of canine heartworm disease is as follows:

Dog Weight Tablets Per Month Ivermectin Per Tablet Color on Carton
Up to 25 lb 1 68 mcg Blue
26 to 50 lb 1 136 mcg Green
51 to 100 lb 1 272 mcg Brown

Give dogs over 100 lb the appropriate combination of tablets.

Heartgard is recommended for use in dogs 6 weeks of age and older.


The Heartgard tablet should be given so that dogs swallow the whole tablet. (The tablet may be wrapped in food to encourage consumption.) Care should be taken to see that the dog consumes the complete dose, and treated animals should be observed for a few minutes after administration to ensure that part of the dose is not lost or rejected. If it is suspected that any of the dose has been lost, redosing is recommended. Heartgard Tablets should be given at monthly intervals during the period of the year when mosquitoes (vectors), potentially carrying infective heartworm larvae, are active. The initial dose must be given within a month (30 days) after the first exposure to mosquitoes. The final dose must be given within a month (30 days) after the last exposure to mosquitoes.

When replacing another heartworm preventive in a heartworm disease preventive program, the first dose of Heartgard must be given within a month (30 days) after the last dose of the former medication.

If the interval between doses exceeds a month (30 days), the efficacy of ivermectin can be reduced. For optimal performance, the tablet must be given once a month on or about the same day of the month. If treatment is delayed, whether by a few days or many, immediate treatment with Heartgard and resumption of the recommended dosing regimen minimizes the opportunity for the development of adult heartworms.


Heartgard Tablets, given orally using the recommended dose and regimen, are effective against the tissue larval stage of Dirofilaria immitis for a month (30 days) after infection and, as a result, prevent the development of the adult stage.


All dogs should be tested for existing heartworm infection before starting treatment with Heartgard® (ivermectin) Tablets, which is not effective against adult D. immitis. Infected dogs must be treated to remove adult heartworms and microfilariae prior to initiating a program with Heartgard.

While some microfilariae may be killed by the ivermectin in Heartgard at the recommended dose level, Heartgard is not effective for microfilariae clearance. A mild hypersensitivity-type reaction, presumably due to dead or dying microfilariae and particularly involving a transient diarrhea, has been observed in clinical trials with ivermectin after the treatment of some dogs that have circulating microfilariae.

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.

Adverse Reactions:

The following adverse reactions have been reported following the use of Heartgard: Depression/lethargy, vomiting, anorexia, diarrhea, mydriasis, ataxia, staggering, convulsions and hypersalivation.


Heartgard has shown a wide margin of safety at the recommended dose level in dogs (See Precautions for exceptions) including pregnant or breeding bitches, stud dogs, and puppies aged 6 or more weeks. In clinical trials, many commonly used flea collars, dips, shampoos, anthelmintics, antibiotics, vaccines, and steroid preparations have been administered with Heartgard in a heartworm disease preventive program.

Studies with ivermectin indicate that certain dogs of the Collie breed are more sensitive to the effects of ivermectin administered at elevated dose levels (more than 16 times the target use level) than dogs of other breeds. At elevated doses, sensitive dogs showed adverse reactions which included mydriasis, depression, ataxia, tremors, drooling, paresis, recumbency, excitability, stupor, coma and death. Heartgard demonstrated no signs of toxicity at 10 times the recommended dose (60 mcg/kg) in sensitive Collies. Results of these trials support the safety of Heartgard products in dogs, including Collies, when used as recommended.


Store at controlled room temperature 68° - 77°F (20° - 25°C).


Can cause sensitivities in herding dog breeds. It is important that you give your pet this preventative every month. If you miss more than two monthly doses, we recommend calling your vet before continuing the medication. Also, note that side effects are rare at the recommended heartworm prevention dose. Higher doses in dogs may cause tremors, dilated pupils, loss of body weight, and death. Side effects in cats include agitation, loss of appetite, staggering, dilated pupils, tremors, blindness and disorientation.


Give the missed dose as soon as you remember. Do not give a double dose of the medication.
Seek emergency veterinary medical treatment. Symptoms of overdose may include vomiting, diarrhea and lack of coordination in dogs.
To help with compliance and not missing a monthly dose, use the handy red heart reminder stickers included with the medication.
Side effects of Heartgard are rare at the recommended heartworm prevention dose. Higher doses in dogs may cause tremors, dilated pupils, and loss of body weight and death.
Do not give Heartgard to your pet if already taking another heartworm medication.
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.
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.
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.
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.
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.
Pet owners can use Heartgard (ivermectin), the #1 veterinarian-recommended preventive on the market 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 dog, heartworm larvae mature into adults and ultimately migrate to the arteries of the lungs.
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.
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.
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.
No, the way dogs become infected is via a bite from a mosquito that is carrying heartworm larvae.
No. Puppies that are nursing may become infected. Heartgard can be used in puppies as young as 6 weeks of age and puppies benefit from the ability of Heartgard to treat and control roundworms and hookworms.


Review Summary
12 Reviews
92% (11)
8% (1)
0% (0)
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100% Recommend this product (12 of 12 responses)
By Glenna H.
December 13, 2020
Very happy with service.
Thank you.
By Nancy C.
Online Pharmacy Order
November 11, 2020
Communication was terrific. Very efficient service. Highly recommend!
By MommaKatt
Great Pricr
October 1, 2020
My vet recommends this but the cost on Entirely Pets is so much better than at the Vets Office
Good Price
June 29, 2020
This was a good price but I will get it from the Vet next time. Keep it local
By Rafjr13
March 8, 2020
We've been using Heartguard on our dog for about 8 years. Will reorder again.
By Kelly
Lindenhurst, IL
Prefer this over the new competition
October 23, 2019
I've been using Heartguard for almost 30 years on all my pets. My vet recently recommended Iverhart Plus as a second option regarding heartworm prevention. I agreed to try it and came right back to Heartguard. The dogs much prefer the chewable than the tablet Iverhart has.
Thanks Heartguard, for sticking with what works.
Dogs like the taste, I like the ease. Cost
By Richard
Frisco, TX
January 27, 2018
Same product that you would buy from your vet. But you will save quite a bit.
By Pat
Very easy to use
September 15, 2017
Great. Items came quickly and communicated
At each step if order.
Merchant Response:Thank you for the feedback Pat, glad we could help!
By Dan K.
Mechanicsburg, PA
June 9, 2017
My dogs think this medication is a treat. They look forward to getting it monthly. My local vet does not carry this product. Many thanks to Entirely Pets Pharmacy.
By T
Springfield, MO
July 23, 2016
Every order I place with Entirely Pets I receive quality products, excellent costumer service and great delivery. I order most of my dogs supplies from this company. I love Entirely Pets and will continue to place my orders here.
By Sally J.
A once again satisfied returning customer
May 17, 2015
Entirely Pets is a great source for conventional meds as well as medication supplements for pets. Their prices are competitive if not less then other online pet pharmacies and their service is very efficient. The pet meds I ordered were @ my house in just a few days. I have been getting my little dogs Hearguard from another online pharmacy but they were not able to beat Entirely Pets prices and b/c I use too order meds from Entirely Pets, and was always satisfied, I decided to place my order once again w/ them. Thanks Entirely Pets for your consistent online ordering made easy.
By Philica
Mountain Grove, MO
It was great.
April 10, 2015
I have used this for the life of both my pets. As per their yearly tests, they have both been Heartworm free every year. This is a very good product and I would not use any other. Entirely Pets Pharmacy has made receiving this product very easy and cost efficient.

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