View our How to manage Heartworms video.
What is Heartgard?
Heartgard is a monthly oral pet med used in dogs and puppies as a heartworm preventive.
Who is it for?
Dogs and puppies over 6 weeks. Safe for pregnant/breeding females.
What are the benefits?
||Prescription pet med prevents heartworm infection in dogs and puppies
||Heartgard dog medication comes in convenient chewables
||Easy once-a-month administration
How does Heartgard work?
Heartgard is used in the prevention of heartworm infections. It kills the immature form of the heartworm (Dirofilaria immitis). Heartgard contains ivermectin, which interferes with the parasite's nerve transmission, causing paralysis and death of the immature heartworms (larvae).
Is there a generic equivalent available?
We do not carry a generic form of Heartgard tablets/chewables.
How is it given?
Heartgard must be administered monthly, preferably on the same date each month. Drs. Foster and Smith recommends (and our guarantee requires) that Heartgard be given year round, although some veterinarians may recommend giving it only during the mosquito season. If given seasonally, the first dose must be given within 30 days of the dog's first exposure to mosquitoes. The last dose must be given within 30 days after the dog's last exposure to mosquitoes.
Remove only one Heartgard Chewable at a time from the foil-backed blister card. Put the remaining Heartgard Chewables back into the box to protect from light. Most dogs like the taste of Heartgard Chewables and will accept the chewable tablet as a treat. The chewable should be administered in a manner that encourages the dog to chew, rather than to swallow without chewing. Heartgard Chewables may be broken into pieces and fed to dogs that normally swallow treats whole. Care should be taken 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 not entirely consumed, give another full recommended dose as soon as possible.
What results can I expect?
Heartgard will kill the immature heartworms the dog was exposed to in the preceding month.
What form(s) does it come in?
Please click on "More Information" for possible drug and food interactions with this medication.
Heartgard for Dogs
Common Drug Name
What should I discuss with my veterinarian while considering Heartgard?
Talk to your veterinarian about the heartworm testing that is recommended before starting your dog on a heartworm prevention program.
Collies or other herding breeds may have a reaction to ivermectin if given over the recommended heartworm prevention dose. If your dog is one of these breeds, and your veterinarian has prescribed Heartgard, observe your pet for at least 8 hours after giving the medication for weakness, staggering, dilated pupils, trembling, drooling, or pressing the head against a wall. Contact your veterinarian immediately if you see these signs.
Notify your veterinarian of any other medications or supplements your dog is taking, and also if your dog has had any reactions to previous medications.
What should I do if I miss a dose?
If a dose is missed and over 30 days have gone by since the last dose, give Heartgard immediately and resume the monthly dosing schedule. Tell your veterinarian that a dose was missed.
What is the most important information I should know?
If the interval between doses is longer than one month, the efficacy of the drug is reduced.
Who should not take it?
Do not use in puppies less than 6 weeks of age. Considered to be safe to use in pregnant and lactating dogs (female animals nursing their young).
Collies and herding breeds may have a reaction to Heartgard.
This medication should only be given to the pet for which it was prescribed.
What side effects may be seen when taking Heartgard?
Side effects of Heartgard are very rare, but may included vomiting and diarrhea. Even more uncommon ar incoordination, convulsions, or drooling. Contact your veterinarian immediately if you observe these signs.
How is it stored?
Store between 68°F-77°F (20°C-25°C). Short time periods between 59°F-86°F (15°C-30°C) are permitted. Protect product from light. The chewable form of the drug is appealing to pets and children. Store in a secure area to prevent an accidental overdose.
What should I do if I know of or suspect there has been an overdose?
If you know or suspect your pet has had an overdose, or if you observe diarrhea, vomiting, incoordination, convulsions or drooling, contact your veterinarian immediately.
What should I avoid when giving my pet Heartgard?
Although there are no known drug or food interactions with this medication, consult with your veterinarian before using Heartgard with any other medications, including vitamins and supplements, since interactions may occur.
Where is more information available?
Ask your veterinarian, consult with one of our pharmacists at 1-800-447-3021, or see the Patient Information Sheet on this medication. For technical assistance or to report suspected adverse reactions, call the manufacturer, Merial, at 1-888-637-4251.