Last Updated: 31/03/2026
Best Heartworm Treatment for Your Dog
Wondering about which heartworm medicine is best for your dog? Our Vet team compares treatments
Author: Dr Carla Paszkowski BVSc (Hons)
Reading Time: 7 minutes - short read
Heartworm prevention is one of the most confusing topics surrounding dog ownership. Not too long ago, dog owners had only one choice to protect their dog against heartworm: a daily tablet.
Nowadays, thanks to advances in veterinary medicine, there are a whole variety of ways to protect your dog for heartworm. Monthly chewables, a yearly injection, and even topical treatments are all available for you to choose from.
But, which heartworm prevention method is the best? Is the yearly heartworm injection more effective than monthly chewables? Which is the best value, and most importantly - which is the safest?
The truth is, there is no 'one size fits all' best treatment. Different regimes work better for different households. As a guide, we've taken you through all options available and listed the pro's and cons, so you can make up your own mind.
Whichever heartworm prevention you choose, it's important you remember to give it on time. If your dog's prevention has lapsed, you may need to test them for heartworm before recommencing their heartworm preventative, and your vet will be able to advise the best course of action. Likewise, if you adopt an adult dog with an unknown history of parasite prevention, you should test before treating. Giving heartworm prevention to a heartworm-positive dog can be deadly.
Not sure what heartworm actually is, or how the disease and prevention works? See our other article Everything you need to know about Heartworm.
1. The yearly heartworm injection
Hidden costs: Because the heartworm injection has no coverage for fleas, ticks, or intestinal worms, you will need to buy extra intestinal worming and flea and tick products throughout the year. Depending on your vet, you may also need to pay for a consultation when you have the needle administered.
Facts: The yearly heartworm injection (Proheart SR12) is an annual needle that lasts for a full twelve months. In growing puppies, a couple of boosters are required (one at 12 weeks of age, another at 6 months, and then again around 12 months of age) but after this, the injection is yearly. The heartworm injection is only available for dogs; currently there is no injection for cats.
How does the yearly heartworm injection work? The heartworm injection is not a vaccine. Instead, it uses microspheres which contain an anti-heartworm compound. Over time, the microspheres gradually dissolve and release their compound, keeping your dog protected for 12 months.
What we recommend pairing it with: Drontal for intestinal worming, and Bravecto for flea and tick prevention. Drontal covers for intestinal worms, but has no heartworm coverage so you won't be doubling up with the injection.
Pros
- Peace of mind knowing that your dog has heartworm protection for a full year (- ie good if you are forgetful!)
- Generally 100% effective if injected correctly
- No tableting required
Cons
- Can be costly in larger dogs
- Requires a visit to the vet and large-gauge needle injection (can be stressful for some dogs)
- Hidden costs are high - as there is no coverage for intestinal worms or fleas and ticks, so you will have to buy these on top (we recommend Drontal for intestinal worming, and Bravecto for flea and tick prevention.
2. An oral monthly heartworm product
Products in this category:
- Intestinal worming + heartworm combination products (like Heartgard (no whipworm or tapeworm protection), Interceptor, Milpro and Milbemax)
- Intestinal worming + heartworm + flea combination products (like Nexgard Spectra, Simparica Trio and Credelio Plus).
- Heartworm-only products - are uncommon these days.
For the purpose of this comparison, we are only going to discuss the first two options. Combination products which include at least intestinal worms as well are always recommended over heartworm-only products, for your own convenience. If you select a heartworm-only monthly product, you will need to pair it with both an intestinal wormer like Drontal, as well as a flea product like Simparica. (Save yourself the hassle of having to give three separate products - go for a combination product from the start!)
Hidden costs: None, if you select a comprehensive product like Nexgard Spectra, as your parasite prevention will be complete (apart from the hydatid tapeworm).
However If you choose a worm/heartworm-combination product like Interceptor or Milbemax, you will need to buy another product for fleas (and ticks, if this is a risk in your area).
Facts: Monthly oral heartworm prevention usually contains a drug such as milbemycin or ivermectin, which belong to the macrocyclic lactone family. The intention of monthly heartworm prevention is to kill any 'baby' heartworm larvae before they mature into adults. Due to the lifecycle of heartworm, monthly administration is sufficient to prevent this maturation stage from occurring.
What we recommend pairing it with: If you choose a monthly oral combination product like Simparica Trio, Credelio Plus or Nexgard Spectra, you will just need to pair it with a tapewormer either every 6 weeks for dogs at high risk of hydatid tapeworm (dogs who eat raw meats, offal or have access to animal carcasses), OR once every 3 months for all other dogs. Tapeworm-only tablets are available from your vet clinic, or all-wormers like Drontal or Paragard with tapeworm coverage can be safely used.
However if you choose a worm-heartworm only combination product, we recommend pairing it with a monthly flea and tick preventative like Simparica or Nexgard (not to be confused with their all-in-one relatives above). These are monthly, which means all your preventatives will line up monthly.
Pros
- Generally 100% effective if given on time
- Tasty chewables available (no needle required!)
- Combinations available for convenient all-in-one parasite prevention
- Affordable long term, due to minimal (if any) extra purchases required
Cons
- Must be remembered on time - not ideal for forgetful dog owners
- More frequent administration than a yearly injection
- Difficult in fussy dogs who won't take worming chews
Best Oral Monthly Heartworm Products
3. A topical monthly heartworm product
Hidden costs: You may need to buy an intestinal wormer and an extra product for tick prevention, if you live in a tick area.
Facts: Topical heartworm prevention usually contains a drug from the macrocyclic lactone family, such as selamectin or moxidectin. Macrocyclic lactones work similar to the oral preventatives, by killing baby heartworm larvae. The intention of monthly heartworm prevention is to kill any 'baby' heartworm larvae before they mature into adults. Due to the lifecycle of heartworm, giving monthly is sufficient to prevent this maturation stage from occurring.
What we recommend pairing it with: Depending on the product you use, intestinal worm protection may or may not be included, so if you choose Neovela, you will need to pair it with an all-wormer such as Drontal.
Tapeworms are not covered in any of the products, so you will need to pair it with a tapewormer either every 6 weeks for dogs at high risk of hydatid tapeworm (dogs who eat raw meats, offal or have access to animal carcasses), OR once every 3 months for all other dogs. Tapeworm-only tablets are available from your vet clinic, or all-wormers like Drontal or Paragard with tapeworm coverage can be safely used.
Ticks are not covered in any of the products. If you are in a paralysis tick area - which includes the entire East Coast of Australia - we recommend pairing with a reliable tick preventative like Bravecto, Simparica or Nexgard. If you live in an area affected by Brown Dog Ticks, we recommend pairing with a kill-and-repel tick product such as Seresto.
For a full guide to the type of tick prevention YOUR dog needs, take a look at our Guide to Fleas and Ticks in Dogs.
Pros
- Generally 100% effective if given correctly and on time
- Topical administration - great for fussy dogs who won't eat chews
- Combinations available for fleas and worms
Cons
- Must be remembered on time - not ideal for forgetful dog owners
- More frequent administration than a yearly injection
- Hidden cost: You may need to purchase extra tick prevention depending on your area
4. A daily heartworm tablet
Products in this category: This type of medication is mostly phased out these days, but Diethylcarbamazine (DEC) tablets are still available for daily administration.
Hidden costs: You will need to purchase a separate product for fleas and ticks and another product for intestinal worming. It is also recommended that dogs treated with daily heartworm medication undergo a heartworm test every 6 months.
Facts: Once the only option available for heartworm prevention in dogs, daily medication was originally commonplace but is now mostly phased out. It has completely disappeared from overseas markets but is still available in Australia. Containing the drug diethylcarbamazine, these tablets need to be given daily; even missing just two days can put your dog at risk of contracting heartworm. (ie: monthly prevention is much more convenient and safe!)
What we recommend pairing it with: To be honest, we don't recommend daily heartworm medication at all, as there are so many monthly options available nowadays. But if you do choose to use a diethylcarbamazine-containing product, we suggest pairing it with Drontal for intestinal worming, and Bravecto for fleas and ticks.
Pros
- Affordable at face value (but other costs are involved)
Cons
- Must be given every day - even two missed days can put your dog at risk.
- Costly in the long run - as extra products need to be purchased for intestinal worming and fleas, and heartworm tests are required every 6 months.
- Difficult in fussy dogs who won't take tablets
Navigating the world of parasite control can be complex, but the key takeaway is simple: consistent prevention is crucial. As we've seen, options range from a single annual injection to comprehensive monthly chews and topical applications.
There is no single "best" product, only what is best for you and your dog. By considering your ability to remember doses, your budget, and the need for additional flea, tick, and worming coverage, you can create the perfect defence against heartworm.
Reach out to our Vet Squad to discuss the best heartworm protection for your dog.
Heartworm FAQs
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History
Our experts continually monitor the health and wellness space and we update our articles when new information becomes available.
Tue Feb 14 2023
Written by Dr Carla Paszkowski BVSc (Hons)Dr Carla Paszkowski BVSc (Hons)
Veterinarian
Dr. Carla graduated from the University of Queensland in 2013 with a Bachelor of Veterinary Science and worked for a number of years in small animal clinics across South East Queensland. While Carla enjoys most facets of clinical veterinary work, she holds a special passion for feline medicine, pocket pets, and nutrition.
