Heartgard Plus: The Chewable That Most Dogs Actually Want to Eat
Heartgard Plus prevents heartworm disease, which is fatal if untreated and expensive to cure. The medication itself is straightforward. Getting it without overpaying takes a little more work. Here is what I found after comparing prices across 5 online pharmacies.
BudgetPetCare
Code FATHER for 25% off sitewide
What Heartgard Plus Does
Heartgard Plus is a monthly chewable that prevents heartworm disease and treats roundworms and hookworms. The active ingredients are ivermectin (heartworm prevention) and pyrantel pamoate (roundworm and hookworm treatment).
Heartworms are transmitted by mosquitoes. One bite from an infected mosquito, and larvae enter your dog's bloodstream. They grow into foot-long worms that live in the heart and lungs. Treatment for an active heartworm infection involves arsenic-based injections, months of cage rest, and a bill that starts around $1,000 and can go past $3,000 for large dogs.
A monthly chew that costs $5-8 online is a much better deal than treating heartworm disease. Every vet I have ever spoken to agrees on this point.
Quick Facts
- Real beef chew, most dogs eat it like a treat
- Prevents a fatal disease for $5-8/month
- Also kills roundworms and hookworms
- Safe for puppies 6+ weeks
- Available online at 40-50% off vet prices
- Prescription required
- Does not cover fleas or ticks
- Does not cover whipworms
- Must give every 30 days, missing doses is risky
- Some collie breeds need testing for MDR1 gene sensitivity
Price Comparison: 12-Month Supply (Medium Dog, 26-50 lbs)
| Pharmacy | 12-Month Price | Best Coupon | Per Month |
|---|---|---|---|
| BudgetPetCare | $62 | FATHER (25% off) | $5.17 |
| CanadaPetCare | $68 | CPC12ON (12% off) | $5.67 |
| BestVetCare | $65 | BIGBONUS (up to $25 off) | $5.42 |
| Chewy | $98 | none | $8.17 |
| Vet Clinic (avg) | $110 | none | $9.17 |
The difference between buying online and at the vet is about $48 a year for Heartgard Plus alone. If you have two dogs, that doubles. Add NexGard into the mix and the annual savings hit $200-400 for a multi-pet household. All prices checked June 2026.
Side Effects: What the Label Says vs What Happens
The official side effects listed by the manufacturer are diarrhea, vomiting, and lethargy. In real use, these are uncommon. Ivermectin has been used in dogs for decades and the safety profile at heartworm prevention doses is extremely well established.
The one real concern is the MDR1 gene mutation, which affects some herding breeds (collies, Australian shepherds, shelties, and crosses). Dogs with this mutation are more sensitive to ivermectin and can have neurological reactions even at Heartgard's low dose. A genetic test costs about $50-70 and is a one-time thing. If your dog is a herding breed or mix, it is worth doing.
At heartworm prevention doses, even MDR1-affected dogs generally tolerate Heartgard Plus fine. The problem doses are much higher, which is why this medication is safe for monthly use and ivermectin-based mange treatments (which use 10-50x the dose) are not.
Active Coupons for Heartgard Plus
Bottom Line
Heartgard Plus costs about as much as a coffee per month and prevents a disease that costs more than a used car to treat. There is no good reason to skip it. Buy it online, save about half what your vet charges, and set a calendar reminder so you do not miss a dose.
If you need flea and tick coverage too, pair it with NexGard or Frontline Plus. Do not skip heartworm prevention because a flea chew "covers everything." Most flea chews do not cover heartworm, and the ones that do (Simparica Trio) cost more than buying them separately.
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