Can I Give NexGard And Heartgard At The Same Time?

Have you recently found yourself with an itchy pooch, pondering,

Is Heartgard the same as Nexgard? Can I give Nexgard and Heartgard at the same time?”

Well, it’s your (and mine- thank you for visiting my site!) lucky day- we’re going to be discussing that topic right here in this article!

Here’s the short answer: It is absolutely fine to give Nexgard and Heartgard at the same time to your beloved pup.

Not only is it absolutely fine, it’s usually highly recommended by vets that pet owners do so.

This is because the two prevention products each protect against different parasites; NexGard for flea and tick infestations, and Heartgard specifically for heartworm infections.

Both work well in tandem with each other, and there is nothing in the way of contraindications.

Most importantly, keeping your dog up-to-date on their flea and worm treatments will protect its body against some otherwise nasty critters!

Let’s dive a bit deeper into both NexGard and Heartgard as protective medications, how they work in conjunction with each other, and any potential adverse side effects they might have on a dog!

Can You Give Dewormer And Heartgard At The Same Time?

Man giving his dog worm tablet

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As we’ve already briefly touched on above: Yes, it’s completely A-Ok to give your dog a dewormer like Nexgard with Heartgard simultaneously!

Both are medications that can be given orally (mmm…beef flavor) and which will work symbiotically with each other to provide total protection from external and internal parasites.

In fact, they are marketed by the company themselves as being the “Perfect Pair” to be given together once a month.

Is NexGard And Heartgard The Same Thing?

NexGard and Heartgard most definitely are NOT the same thing.

Before you can understand the differences between Nexgard and Heartgard, you need to be familiar with the ingredients and purpose of each.

By doing so, you will be able to see the differences between the drugs much more easily.

Breakdown Of Each Medication


  • Active Ingredient: Afoxolaner
  • Kills Fleas, Flea Eggs, and Ticks: Yes
  • Repels Fleas, Ticks, and Mosquitos: No
  • Prevents Heartworm: No
  • Other Parasite Protection: No
  • Prescription Required: Yes
  • Dose: One oral pill per month
  • Age: Eight weeks of age and older (must weigh at least four pounds)


  • Active Ingredient: Ivermectin and pyrantel pamoate
  • Kills Fleas, Flea Eggs, and Ticks: No
  • Repels Fleas, Ticks, and Mosquitos: No
  • Prevents Heartworm: Yes
  • Other Parasite Protection: Roundworms and hookworms
  • Prescription Required: Yes
  • Dose: One oral pill per month
  • Age: Six weeks of age and older

As you can see clearly from these stat sheets, NexGard and Heartgard protect against vastly different parasites. NexGard targets fleas and ticks, while Heartgard safeguards against heartworms and intestinal worms.

Potential Side Effects

Is heartworm medicine really necessary

Before we get into the safety precautions of taking Nexgard and Heartgard together, let’s take a look at the side effects of each first which you may see in your pup after administering these drugs.

Nexgard Side Effects

Nexgard falls into a category of drugs known as “ isoxazolines.” According to the FDA, isoxazoline class drugs can cause neurologic reactions in dogs, although an event of this sort is rare.

Of the rare side effects, the ones most often reported include muscle tremors and a loss of balance (also known as ataxia).

Another side effect, although less common than the others, is seizures.

If your dog has a history of seizures, they are more likely to have one after taking Nexgard than a dog with no previous seizure history.

Therefore, this is something to be careful of; definitely consult with your vet closely if this applies to your pet.

Heartgard Side Effects

Although still rare, Heartgard seems to have a wider list of potential side effects- so much so that some dog owners actively search for viable alternatives to Heartgard.

Don’t be put off straight away though. Heartgard is extremely safe for most dogs; so much so that they would likely be in the clear even if they accidentally ate two, or three… or even ten!

The most common side effects of Heartgard include diarrhea and vomiting within 24 hours of administering the drug. You may also notice that your dog is less active than before taking the drug.

The rarest side effects include unusual dilation of the eyes (mydriasis), ataxia, staggering, seizures, and hypersalivation.

Studies have shown that some dog breeds, specifically herding breeds like Collies and Shepherds, are more likely to have a genetic mutation that makes them more sensitive to the ivermectin component of heartworm medications.

This genetic mutation is of the MDR1 gene, which directly affects how well medication penetrates the blood-brain barrier. As a result of the heightened sensitivity, dogs that are affected experience pronounced neurological symptoms.

As always, it pays to keep on top of these issues with your vet so that you know what medications your dog can and cannot have.

Keep your eyes out for the less extreme side effects because they often are a precursor to more severe side effects that may soon occur.

So, Can Dogs Take Heartgard and Nexgard Together?

Confused dog head tilt

In short, as long as your dog is above the age and weight requirements listed in the above “Breakdown” section, they can take Heartgard and Nexgard together.

Most vets encourage their patients to use both drugs because neither medication protects against all insects or parasites by itself.

Heartgard protects your dog against parasites like heartworm, roundworm, and hookworm, while Nexgard protects against insects like ticks and fleas.

By using both at the same time, you can ensure your pup is protected against deadly diseases like Lyme disease and parasitic infestations.

What if My Dog Hasn’t Tried Either Drug?

If your dog hasn’t tried either of the drugs, make sure you tell your vet when you go in for the prescription. They’ll give you the best advice and tell you how to properly administer the drug in a controlled way.

In reality, the best way to introduce new drugs to a dog is by giving them one medication at a time. So if you were to get both Nexgard and Heartgard, choose one drug to give immediately and the other in 24 hours.

Why should you wait 24 hours? By that point, you should notice any of the side effects your dog will experience. Since you’ve only given your dog one medication, you’ll know which one is causing the negative side effects.

But if you’ve already tested out these medications on your dog and found there were no severe side effects, go ahead and give both at the same time.

Boehringer Ingelheim, the manufacturer of both medications, even advertises that giving your dog both medications simultaneously is safe and effective.

Do I Need Heartgard if I Use Nexgard?

By this point in the article, you should be well aware that Heartgard and Nexgard protect your dog against totally different infections.

Although you don’t need to use Heartgard if you use Nexgard, or vice versa, by using both, your dog gets protection against the highest number of parasites and diseases.

However, if your dog has an adverse reaction to one or both medications, you can switch them to an equivalent medication that protects against the same things but doesn’t cause side effects. Before you switch medication, always talk to your vet.

They will tell you if the protections are the same in different medications and if they have adverse interactions with other drugs your dog may be taking.

Nexgard and Heartgard were formulated so they could be given together, but it’s important to note that not all drugs are like that!

Frequently Asked Questions

FAQ magnifying glass

Here are the most commonly-asked questions about Nexgard and Heartgard.

I Gave My Dog Nexgard, But They Still Have Fleas. What’s Going On?

Nexgard is an effective flea-killing treatment, so if your dog continues to get flea infections after using the medication, an environmental factor is likely at play.

Fleas are most often found outside and brought inside your home in your dog’s fur. Once they’re inside, it can be hard to get them out.

If your home or yard has a flea infestation, it would explain why your dog continues to get infected by fleas. Fleas like to hide in your furniture or carpets as well after all.

To get rid of a flea infestation in your home, you may need to enlist the help of professional exterminators. Once done, your dog should be flea-free!

For more information on the vet-recommended ways to treat fleas in pregnant and lactating dogs, read our post HERE! 

Is Heartworm Deadly?

Heartworm is a potentially deadly disease caused by the parasite Dirofilaria immitis.

Once your dog is infected, worms begin to grow and circulate through the bloodstream, ultimately coalescing in their heart and the main arteries.

It may take years for serious symptoms to appear in your dog. Once symptoms occur, they’re caused by the worms constricting the flow of blood through the heart. That, among other symptoms, can cause your dog to die.

If My Dog Has a Tick, Can I Remove It?

Every once in a while, you may see a tick attached to your dog. Luckily, Nexgard kills the ticks, but their dried, dead bodies may be left attached to your dog.

If you want to remove a tick from your dog, you’ll need rubbing alcohol and tweezers.

Firstly, grasp onto the body of the tick firmly with the tweezers, and then gently pull the tick out of your dog’s skin without twisting. If you twist, you may break the tick in half, leaving its head embedded in your dog’s skin.

Try your best not to grasp the tweezers so tightly that it punctures, squeezes, or squashes the tick, even if it is already dead.

Doing so can create unnecessary infection risks, whether from pushing disease-causing bacteria straight into the bloodstream, or via the stomach contents of the tick contaminating the surface of the dog’s skin.

After you remove the tick, pour rubbing alcohol onto a paper towel and sanitize the area thoroughly. Antiseptic ointments like Neosporin can be applied as well if the area is looking a bit red and inflamed.

To learn all you need to know about removing ticks (live or dead) from dogs, have a read of our comprehensive article HERE!

In Summary

In the future, when someone wonders, “Can I give NexGard and Heartgard at the same time to my dog?” You’ll know the correct answer without even needing to think about it.

Yes, it’s completely fine!” You’d blurt out in uncontainable excitement. “In fact, it’s the recommended method of administration by both qualified vets and the manufacturing company!”

No doubt after that you’ll become the undisputed canine guru in your friend group.

By providing your pup with NexGard and Heartgard monthly at the same time, you’ll be doing your part as a responsible owner to protect them from parasites such as fleas, ticks, intestinal worms, and heartworms.

With little-to-no side effects experienced by most dogs, it’s really a no-brainer to make sure that your dog stays on a consistent heartworm, flea, and tick preventative treatment throughout its lifetime!

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