Heartworm disease is a serious, mosquito-borne illness that can cause long-term damage to a dog’s heart and lungs. The safest approach is prevention: monthly heartworm preventives are designed to stop heartworm larvae from developing into adult worms.
Important: This guide is general information only and doesn’t replace veterinary advice. Always follow the product label and your veterinarian’s guidance—especially if your dog has existing health conditions, is underweight/overweight, is pregnant/nursing, or is taking other medications.
Shop Heartgard Plus & Heartworm Protection at Smartway
What Is Heartgard Plus?
Heartgard Plus is a monthly chewable for dogs formulated with ivermectin (to help prevent heartworm disease) and pyrantel pamoate (to help treat/control certain intestinal worms, commonly roundworms and hookworms).
Because heartworm risk is driven by mosquito exposure, many veterinarians recommend maintaining consistent, year-round prevention (even if you don’t see mosquitoes every day).
Heartgard Plus Weight Chart
Heartgard Plus is dosed by your dog’s current body weight. Weigh your dog regularly—especially growing puppies or dogs whose weight changes seasonally.
| Dog Weight | Common Pack Color | Typical Monthly Dose | Shop Heartgard Plus |
|---|---|---|---|
| Up to 25 lbs (0–11 kg) | Blue | 1 chew monthly | Heartgard Plus Blue (Up to 25 lbs) |
| 26–50 lbs | Green | 1 chew monthly | Heartgard Plus Green (26–50 lbs) |
| 51–100 lbs | Brown | 1 chew monthly | Heartgard Plus Brown (51–100 lbs) |
Dogs over 100 lbs: Larger dogs may require a veterinarian-recommended dosing approach (for example, combining chew sizes). If your dog is over 100 lbs or between weight bands, confirm the best option with your vet so your dog stays properly protected.
How Heartgard Plus Works
Heartworm infection begins when a mosquito transmits microscopic heartworm larvae. Monthly preventives work by eliminating larvae acquired during the previous month, helping stop them from developing into adult heartworms. That’s why monthly dosing matters—staying consistent helps maintain continuous protection.
How to Give Heartgard Plus
- Give once monthly on the same date (or close to it) every month.
- Offer the chew like a treat or with a small amount of food.
- Make sure your dog consumes the full dose (some dogs try to spit out part of the chew).
- If your dog tends to swallow treats whole, you can break the chew into smaller pieces to help ensure it’s fully eaten.
If you miss a dose: Give the missed dose as soon as you remember and continue monthly from that point. If multiple doses are missed—or you’re unsure what to do—contact your veterinarian for guidance.
Side Effects and Safety: What to Watch For
Most dogs tolerate Heartgard Plus well when used as directed. Like any medication, side effects can occur. Some dogs may experience mild digestive upset (such as vomiting or diarrhea), especially soon after dosing.
Contact your veterinarian promptly if you notice unusual symptoms such as severe lethargy, persistent vomiting/diarrhea, tremors, wobbliness, or anything that concerns you.
Important safety notes
- Heartworm testing: Many veterinarians recommend dogs be tested before starting heartworm prevention and tested periodically, especially if doses have been missed.
- Breed sensitivity (MDR1): Some herding breeds can be more sensitive to certain drugs. If you have a Collie-type breed or your dog has a known MDR1 mutation, ask your vet what’s best for your dog.
- Use only for dogs: Always follow label directions and keep medications out of reach of pets and children.
Best Places to Buy Heartgard Plus
To protect your dog (and your wallet), it’s important to buy from reputable sellers who stock authentic product with clear batch/expiry details and proper storage.
Trusted buying options
- Your veterinarian (especially helpful for first-time buyers and dogs with health conditions)
- Reputable pet pharmacies/retailers that clearly list product details and provide support
- Smartway Pet Supplies – Heartgard Plus Range
Prescription note: Heartworm prevention purchasing rules vary by country. Always follow your local requirements and your veterinarian’s advice.
Other Heartworm Protection Options Available at Smartway
Some dog owners prefer an “all-in-one” option that combines heartworm prevention with additional parasite coverage. Smartway stocks a range of heartworm prevention options—browse and compare what suits your dog and lifestyle best.
FAQs
Do I really need to give Heartgard Plus every month?
Yes—Heartgard Plus is designed for monthly dosing. Consistent monthly dosing helps maintain continuous protection, because it targets larvae acquired in the previous month.
Can puppies use Heartgard Plus?
Many heartworm preventives are labeled for puppies from a young age. Always check the product label and confirm with your veterinarian for the safest start date for your puppy.
What if my dog is between weight bands?
Accurate dosing matters. If your dog is near a cutoff, weigh them and ask your veterinarian which size is best—especially if your dog’s weight changes frequently.
Is Heartgard Plus the same as Heartgard?
They both help prevent heartworm disease, but Heartgard Plus typically includes additional intestinal worm coverage. Your vet can help you choose the best option for your dog’s needs.
Final Takeaway
Heartgard Plus is a popular monthly chewable for dogs that helps prevent heartworm disease and provides additional intestinal worm coverage. The key is choosing the right weight band, giving it consistently every month, and buying from a trusted retailer.
Andrew Davies
Founder & Pet Care Specialist — Smartway Pet Supplies
Andrew founded Smartway Pet Supplies to help US and Canadian pet owners access genuine, brand-name parasite prevention medications at fair prices. With years of experience navigating the Australian veterinary products market, he writes practical guides to help pet parents make informed decisions about flea, tick, heartworm, and worming treatments.
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