Heartgard® Chewables for Dogs

Heartgard is a monthly chewable used to prevent canine heartworm disease. It contains ivermectin, which targets heartworm larvae before they mature. Ships from Canada to US through CanadianInsulin to support convenient access for eligible orders.

What Heartgard Is and How It Works

Heartgard® contains ivermectin, a macrocyclic lactone that prevents heartworm disease in dogs by eliminating the tissue stage of Dirofilaria immitis larvae. It interrupts the life cycle after mosquito exposure and before adult worms develop. Some packages target larger breeds, including heartgard for dogs 51 100. CanadianInsulin.com is a prescription referral platform. We verify prescriptions with your prescriber when required, and licensed Canadian pharmacies dispense your order.

This medicine is given once a month. It works systemically after oral dosing and is palatable for most dogs. The treatment helps reduce the risk of heartworm-related complications by keeping new infections from establishing.

For broader parasite control, a veterinarian may recommend options that also cover intestinal worms or external parasites. Read the approved labeling for details on spectrum and safety. Learn more about the condition itself in our overview of Canine Heartworm Disease.

Who It’s For

This prevention is indicated for dogs to stop heartworm disease before it starts. Puppies generally must be at least 6 weeks old to begin prevention. Dogs should test negative for heartworms before starting or restarting a preventive, especially if doses were missed.

Do not use in dogs with a known hypersensitivity to ivermectin. At labeled preventive doses, ivermectin is widely used, but dogs with certain MDR1 gene mutations may be more sensitive to higher exposures. Always consult your veterinarian if your dog is on other medications or has existing health issues.

Some families need broader protection, such as flea, tick, or intestinal parasite coverage. In those cases, a veterinarian may suggest alternatives like Revolution For Dog or Interceptor Flavour Tabs based on your dog’s risk and lifestyle.

Dosage and Usage

Give one chew by mouth once every month, on the same date each month. Your veterinarian will select the appropriate weight band. Offer the chew as a treat or with food if preferred. Ensure your dog consumes the entire dose; if any portion is dropped or spit out, provide a full replacement dose.

For dogs starting prevention for the first time, begin within one month after the first mosquito exposure and continue monthly through the season. Many veterinarians recommend year-round use to simplify adherence and guard against unexpected exposure. If two or more months have elapsed without dosing, testing may be recommended before resuming.

Do not split chews between pets. Keep the monthly schedule consistent. Set a reminder on your phone or calendar to avoid gaps. If you use other parasite preventives, ask your veterinarian how to coordinate monthly schedules.

Strengths and Forms

This medicine is supplied as flavored oral chews in weight-based packs. Common weight ranges include up to 25 lb, 26 to 50 lb, and 51 to 100 lb. The brown pack is designed for larger dogs, and many owners recognize it as heartgard 51 100 lbs. Actual ivermectin content varies by weight band; for example, the largest pack commonly includes 272 mcg per chew. Availability may vary by pharmacy and region.

Missed Dose and Timing

If you miss a dose, give it as soon as you remember and then continue monthly from that date. Avoid giving two doses on the same day unless directed by your veterinarian. If a significant gap occurs, your veterinarian may recommend testing before restarting due to the heartworm life cycle. Try to dose on a consistent schedule each month to maintain prevention.

Storage and Travel Basics

Store chews in the original packaging at room temperature and protect from moisture and light. Keep out of reach of children and other pets. Do not use if the inner packaging is damaged or if the product appears altered.

When traveling, carry the medication in its labeled carton with your prescription details. Pack enough doses for the entire trip plus a spare. If crossing borders with your pet, bring vaccination and prescription records in case authorities request documentation. Keep reminders on your phone to avoid missed monthly doses while away from home.

Benefits

This monthly prevention is easy to give and typically well accepted by dogs. It targets heartworm larvae before they mature, which helps protect your dog from a serious, potentially life-threatening disease. Weight-banded packaging simplifies selection and dosing based on your dog’s size.

Many families appreciate combining monthly tasks. If your veterinarian recommends additional parasite control, consider whether a single broad-spectrum product or a combination approach best fits your dog’s needs. Products for puppies are available too, such as Revolution Puppies Kittens, for households with young animals.

Side Effects and Safety

• Digestive upset: occasional vomiting or diarrhea
• Lack of appetite: transient decrease in interest in food
• Lethargy: mild tiredness on the day of dosing
• Hypersalivation: short-lived drooling in some dogs

Serious reactions are uncommon at labeled doses. Neurologic signs such as tremors, ataxia, or dilated pupils may occur rarely, especially with overdose or certain concurrent drugs. Dogs with high microfilariae burdens may require closer veterinary supervision. If your dog shows concerning signs, contact your veterinarian promptly or seek emergency care.

Drug Interactions and Cautions

Tell your veterinarian about all medicines and supplements your dog receives. Macrocyclic lactones can interact with drugs that affect P-glycoprotein transport. Use caution with certain flea preventives, high-dose ivermectin exposures, or other therapies known to influence neurologic safety margins. Your veterinarian will determine compatibility with your dog’s regimen.

If your household uses dewormers or broad-spectrum preventives, ask how to coordinate them safely. For example, products like Milbemax are used for intestinal worms; your veterinarian can advise whether to combine or switch to an all-in-one option based on testing and risk.

What to Expect Over Time

Most dogs show no obvious changes after dosing because the goal is prevention. Over time, consistent monthly use helps maintain protection during mosquito season and beyond. Regular annual testing remains important, since no preventive is 100 percent and missed doses can occur.

Build a simple routine. Choose a dosing day that aligns with other recurring tasks, and set two reminders. Keep a spare dose on hand in case a chew is lost or not fully consumed. If your dog is finicky, offer the chew in a small treat or meal to ensure the full dose is eaten.

Compare With Alternatives

Some families need a broader spectrum. If you also need intestinal parasite coverage in a monthly oral product, heartgard plus 51 100 lbs is a familiar brown-pack choice; discuss with your veterinarian whether the added spectrum fits your dog’s needs. Two alternatives dispensed by our partner pharmacies include:

Interceptor Plus: a monthly chewable with milbemycin oxime and praziquantel for heartworm prevention and tapeworm, roundworm, and hookworm treatment.

Proheart 6: an injectable moxidectin option administered by a veterinarian for six-month heartworm prevention, useful for households struggling with monthly adherence.

Pricing and Access

You can review current options and compare Canadian pricing with US delivery from Canada. Check weight-band availability for larger dogs, including heartgard for dogs 51 100 lbs, and choose the pack that fits your pet. If you use other preventives for puppies or multi-pet households, browse our Pet Medications selection to coordinate refills.

Use our site to see available packs and place an order once your prescription is confirmed. Payment uses encrypted checkout. Looking for occasional offers? See our Promotions page for current notices.

Availability and Substitutions

Stock can vary by strength and pack size. If the requested pack is unavailable, your veterinarian may recommend an equivalent weight band or another preventive with similar coverage. For larger breeds, some owners inquire about heartgard plus chewables for dogs 51 to 100 lbs; your veterinarian can advise whether that spectrum is appropriate or if a different product is preferable.

Patient Suitability and Cost-Saving Tips

This preventive may be suitable for most healthy dogs when used as directed. Dogs under 6 weeks old or those with certain medical conditions may need different plans. Always test dogs that may have missed doses, as advised by your veterinarian.

Plan ahead to save time. Consider multi-month fills to reduce gaps, and set automated reminders for dosing and reordering. Coordinate parasite control for all dogs in your home to avoid mixed schedules. When switching products, complete needed testing first and start the new preventive on a clearly defined date.

Questions to Ask Your Clinician

• Is year-round prevention recommended for my region?
• Which weight band is correct for my dog today?
• Should I add intestinal parasite coverage or combine products?
• What testing is needed if a dose was missed?
• Could my dog’s medications interact with ivermectin?
• How should I give the chew if my dog is finicky?
• What signs would require urgent veterinary attention?

Authoritative Sources

For official product details and approved indications, see the manufacturer’s information from Boehringer Ingelheim Animal Health on the manufacturer site for US canine heartworm prevention.

For regulatory context and consumer guidance on heartworm preventives, review the FDA Center for Veterinary Medicine’s overview at the FDA page about preventive medications for pets.

For Canadian product listings and status, consult Health Canada’s Drug Product Database via the Health Canada Drug Product Database search tool.

Order today from CanadianInsulin for convenient access, with prompt, express shipping with temperature-controlled handling when required. Medical disclaimer: This content is for informational purposes only and is not a substitute for professional medical advice.