Skip to main content

Ask the Vet: Heartgard Versus Interceptor For Dogs

Heartgard Versus Interceptor For Dogs

Heartgard versus Interceptor for dogs: what is the difference? Let's face it: heartworm disease in dogs is a very scary condition and as a dog owner, you want to provide the best protection against heartworms and other pesky parasites known to be fond of dogs. Nowadays, there are several heartworm meds for dogs on the market, which one to choose? The issue of choosing one over another is generally a no-brainer considering that veterinarians write the prescription. However, many dog owners wonder about differences. Veterinarian Dr. Ivana Vukasinovic provides clear information about Heartgard versus Interceptor for dogs.

 Heartgard versus Interceptor for dogs, which one s better?

Heartgard versus Interceptor for dogs, which one s better?

Heartworm Disease in Dogs 

Dirofilariasis is a potentially fatal disease caused by parasite Dirofilaria immitis. These 12 inches long roundworms spend their adult lives in the heart, lungs, and blood vessels of a dog's cardiopulmonary system, which can lead to congestive heart failure and death.

Heartworm disease affects dogs, cats, and ferrets, but heartworms also live in other mammal species, including wolves, coyotes, foxes, sea lions and—in rare instances—humans.

The dog is a real host for heartworms, which means they live inside the dog as L4 larvae, juvenile adults and adults that can mate and produce new offspring. Heartworm disease is chronic in its course and signs may include mild cough, loss of appetite and reluctance to exercise.

Left untreated, the number of parasites can increase up to several hundred worms which eventually, will cause damage to the organs and possibly even death. Even when the parasites are gone, damage to the system can affect a dog's quality of life.

The mosquito is a transient host with an essential role in the parasite's life cycle. The mosquito bites the infected animal picking up the baby worms which then mature through stages to infective stage larvae inside the mosquito, and when this mosquito bites another animal, larvae are deposited onto the new animal.

Inside this new natural host, it takes 6 months for the larvae to mature into an adult. Adults can live for 5 to 7 years inside dogs, and with every mosquito season, there is an increased number of parasites overall.

There are two types of heartworm medications – for prevention and therapy. Preventive medications come in several forms including chewable tablets, spot-on and injectable solutions.

[otw_is sidebar="otw-sidebar-1"]

Information About Heartgard Plus

Heartgard Plus is a combination of ivermectin and pyrantel pamoate drugs, used in dogs to prevent heartworm by killing the larvae (tissue stage of larvae) and for treatment of roundworm and hookworm for a period of 30 days.
Heartgard (without the Plus) is just ivermectin without pyrantel.

Both ivermectin and pyrantel are chemicals that affect the nervous system of the worms and impulse transmission through nerves. The result is paralysis, and eventually, the death of the parasite.

Ivermectin works by killing the Dirofilaria immitis larvae that may have infected your dog during the previous 30 days. The larvae are killed in the tissue stage of the cycle and cannot develop into juvenile and adult heartworms, thereby the disease is prevented.

Scroll to Continue

Discover More

Screenshot 2022-11-26 194104

Why Does My Dog Lick Metal Things?

If your dog licks metal things, you may be wondering what may be going on in his mind. Discover several possible causes for a dogs' licking or chewing of metal.

Screenshot 2022-11-06 113459

Why is My Dog's Stomach Swollen on One Side?

If your dog's stomach is swollen on one side, this can be a medical emergency. To play it safe, please have your dog see the vet as soon as possible.


Discover 6 Reasons Why Dogs Hate Having Their Feet Touched

Many dogs hate having their feet touched, to the point of turning nail trims into a nightmare. Discover several possible reasons behind your dog's paw-touching phobia.

Ivermectin is metabolized quickly, so it is recommended to administer Heartgard every 30 days, as prolonged periods between two applications can lead to heartworm infection.

Pyrantel controls and kills hookworms and roundworms.

Before the treatment with Heartgard plus, dogs should be tested for existing infections as this medication is not effective against adult heartworms. In cases of infection, dogs must be treated accordingly before administering Heartgard

Heartgard is safe to use in pregnant and lactating pets, and it is safe for the dog as young as 6 weeks of age and it is not intended for feline use (use in cats). Side effects include depression, vomiting, diarrhea, drooling, and convulsions. Studies have shown that the herding dog breeds (especially Collies) may be more sensitive to elevated levels (16 times the recommended dose).

[otw_is sidebar="otw-sidebar-1"]

Information About Interceptor Plus

Interceptor Plus is a combination of milbemycin oxime and praziquantel and this medication is indicated for the prevention of heartworm disease as well as treatment and control of tapeworm, hookworm, roundworm, and whipworm.

Milbemycin oxime is a broad spectrum antiparasitic effective against worms and mites. Similar to other avermectins, milbemycin oxime blocks signal transfer leading to paralysis and death, but the studies have shown that it is less potent than ivermectin.

Interceptor plus prevents heartworm disease by the same mechanism as all other avermectins, by catching and killing heartworm larvae in L3 and L4 stages. Interceptor plus doesn’t kill adult heartworms so it is necessary to test the dog for a pre-existing infection. This medication cannot kill or repel ticks, so it is important to protect the animal from ticks as well.

Praziquantel is a veterinary drug that controls and kills tapeworms.

This drug is safe for dogs starting at 4 weeks of age, but some herding dog breeds such as collies may be more sensitive and may have adverse reactions including coma, seizures, and death. Side effects may include depression, vomiting, diarrhea, drooling, and seizures.

Heartgard Versus Interceptor For Dogs

Heartgard versus Interceptor for dogs, which one is better? When comparing these two drugs, Interceptor Plus has a wider spectrum, and it also includes prevention treatment against hookworms, tapeworms, roundworms, and whipworms, while Heartgard doesn’t protect against whipworms or tapeworms.

Interceptor may be less potent against heartworm larvae, but the dosing of the drug is better in Interceptor plus formulation than in Heartgard plus. When it comes to pricing, Heartgard is considered the more affordable drug.

In both cases, you should discus proper choice with your veterinarian.

About the Author 

Dr. Ivana Vukasinovic is a veterinarian in Belgrade, capital city of Serbia. She received her B.S from University of Belgrade in 2012, and her master’s degree from Veterinary University, Belgrade


[otw_is sidebar="otw-sidebar-2"]

Related Articles