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Simparica vs NexGard: A Tale of Two Flea and Tick Fighters

simparica vs nexgard

Last Updated: March 15, 2024 by Lisa Melillo

Imagine this: It’s a beautiful morning, and you’re out for a walk with your best furry friend. The sun is shining, the birds are singing, and then you see it—a flea. Just one tiny flea leaping onto your dog, and suddenly, the day takes a turn. As a seasoned veterinary technician and a dog parent myself, I’ve been there more times than I can count. It’s the start of a battle many of us know too well. And in this fight, our weapons of choice? Simparica and Nexgard.

I’ve navigated the maze of flea and tick prevention options, from collars to shampoos and everything in between. Through my professional lens and personal trials, I’ve landed on two front-runners: Simparica and Nexgard. Both are popular, but how do they really stack up?

Read on and let’s compare Simparica vs Nexgard. They’re both promising, but if there’s only one winner, what would it be? Let’s find out!

The Importance of Flea and Tick Prevention

Have you ever found a flea or tick on your furry friend? It’s more than just an “ew” moment. These tiny pests are not just a nuisance; they’re a health hazard. Fleas can lead to dermatitis, tapeworms, and anemia, while ticks can transmit serious diseases like Lyme disease and Rocky Mountain spotted fever. Trust me, treating these conditions is something you and your pup want to avoid.

A Brief History of Flea and Tick Prevention

Let’s take a quick stroll down memory lane. Flea and tick prevention has come a long way. In the “good old days,” options were limited. Think powders, dog shampoos, and sprays that were more hit-or-miss than a sure thing. Then came the topical treatments in the 1990s—those drops we’d apply to the back of our dogs’ necks, a big step forward but still a bit messy and, for some dogs, irritating.

Fast forward to the past decade, and oral preventatives have revolutionized the game. These chewable tablets not only made the process cleaner and easier but also proved to be highly effective. It was a breakthrough moment for both vets and pet parents alike.

The Shift to Oral Preventatives

Oral preventatives have become the gold standard for flea and tick control, and it’s not hard to see why. They’re easy to administer (no more wrestling to apply a topical treatment), and there’s no risk of the medication washing off. Plus, many of these options provide a full month of protection from just a single dose.

But it’s not just the convenience that’s won us over; it’s the effectiveness. These medications work by targeting the pests’ nervous systems, killing them before they have a chance to reproduce. And, because they’re ingested, they provide comprehensive protection, reaching every corner of your dog’s body.

Among these modern marvels are Simparica and NexGard—two leading names that have become go-to picks for dog owners seeking reliable flea and tick protection. And if you’re unsure about which one to choose, the next sections can help you make a well-informed decision.

Comparison Table

SIMPARICASimparica Chewable Tablet for Dogs, 44.1-88 lbs, (Green Box)
  • Liver-flavored chewable tablets
  • Kills fleas within 3 hours and ticks within 8 hours
  • Effective even against Gulf Coast Tick
  • Administered once a month


NexGard Chew for Dogs, 60.1-121 lbs, (Red Box)
  • Beef-flavored chewable tablets
  • Kills fleas within 4 hours and ticks within 24 hours
  • Administered once a month


Simparica: What You Need to Know


When Simparica first hit the market, it was met with a mix of curiosity and enthusiasm by the veterinary community and dog owners alike. Its introduction offered a new, potent option for combating fleas and ticks, and it quickly established itself as a reliable choice. As a veterinary technician, I’ve observed its reception firsthand and seen how it’s grown to be a trusted name in pet care.

Simparica is renowned for its fast-acting and long-lasting protection against fleas and ticks. It starts killing fleas within 3 hours and ticks within 8 hours of administration and maintains its effectiveness for a full 35 days. This reliability has garnered significant confidence among pet parents, who value the peace of mind that comes with knowing their dogs are protected from these pests.

Moreover, Simparica has expanded its range with Simparica Trio, a more comprehensive solution that targets fleas, ticks, heartworm, and other parasites in a single dose. This addition has been a game-changer, simplifying parasite prevention by combining multiple protections into one easy-to-administer treatment. The convenience and broad-spectrum efficacy of Simparica Trio have only further solidified the brand’s reputation within the pet care community.

NexGard: What You Need to Know


NexGard burst onto the scene with a promise to revolutionize flea and tick prevention, and it has certainly lived up to the hype. Released to the market with much anticipation, NexGard quickly became a staple in the pet care regimen of dog owners seeking effective and reliable protection against fleas and ticks.

What sets NexGard apart is its pioneering use of afoxolaner, a compound that targets and kills fleas and ticks by overstimulating their nervous system. This mechanism of action has made NexGard exceptionally popular for its efficacy. Dogs love the beef-flavored chew, making administration a breeze—a factor that pet parents greatly appreciate.

The reputation of NexGard as a leading choice for flea and tick prevention is well-earned. It offers a month’s worth of protection with each dose, ensuring that dogs are safeguarded against the discomfort and diseases these parasites can cause. Its impact on the market has been profound, reshaping expectations for what flea and tick treatments can achieve and offering dog owners a highly effective tool in the ongoing battle against pests.

Head-to-Head Comparison

When choosing between Nexgard or Simparica, it’s crucial to consider their effectiveness, safety, and overall value. Both brands have their strengths, but let’s dive deeper to see which one might suit your dog best.

Onset of Effects

In the battle against fleas and ticks, both Simparica and NexGard pack a powerful punch. Simparica claims to start killing fleas within 3 hours and ticks within 8 hours of ingestion, which is impressively fast. This rapid action can be a game-changer in preventing tick-borne diseases that require the tick to be attached for several hours before transmission.

NexGard, while slightly slower, promises to kill fleas within 4 hours and ticks within 24 hours. Its efficacy is still within a time frame that can prevent disease transmission, making it a reliable choice.

The consistent protection both products offer for a full month is a testament to their effectiveness. Whether you’re dealing with a current infestation or looking for preventive measures, both Simparica and NexGard can significantly reduce the risk of fleas and ticks on your dog. Given the slight edge in speed of action, especially against ticks, the winner in this category is clear.

WINNER: Simparica

Efficacy Against Specific Flea and Tick Species

Simparica is known for its broad-spectrum effectiveness, targeting a wide range of tick species, including the Black-legged tick (deer tick), Gulf Coast tick, American dog tick, Brown dog tick, and Lone Star tick. This comprehensive coverage is particularly beneficial in areas where multiple tick species are a concern. For fleas, Simparica is effective against Ctenocephalides felis, the most common flea species that affects dogs.

NexGard, similarly, targets the Black-legged tick, American dog tick, Lone Star tick, and Brown dog tick, providing robust protection against the ticks most likely to transmit diseases to dogs. NexGard is also effective against Ctenocephalides felis, ensuring that dogs are protected from the primary flea species that can cause discomfort and health issues.

Given this distinction, Simparica demonstrates a slight advantage in terms of the breadth of tick protection. This could be particularly relevant for dog owners in areas where the Gulf Coast tick is a common concern, as this species can transmit diseases to both pets and people.

WINNER: Simparica

Mechanism of Action

Simparica utilizes sarolaner, a member of the isoxazoline class, which acts on the nervous systems of fleas and ticks, causing hyperexcitation and eventual death. This is quick and effective, targeting pests at various stages of their life cycle to prevent reproduction and infestation.

NexGard, on the other hand, uses afoxolaner, another compound in the isoxazoline class, which similarly disrupts the nervous system of fleas and ticks with excellent efficacy.

While both medications operate on the same basic principle, their different active ingredients mean they might have slightly varied effects on different pests. However, these differences are minimal in practical terms, as both provide comprehensive protection against the pests they target.


Dosage and Administration

Simplicity and ease of administration are where oral treatments like Simparica and NexGard shine. Both come in a palatable chewable form, making them easy to give to your dog without the mess or fuss associated with some topical treatments.

Simparica is available for dogs weighing at least 2.8 pounds, and NexGard is suitable for dogs weighing 4 pounds and up, making both options accessible for almost all sizes and breeds of dogs.

The once-a-month dosing schedule is convenient, helping pet owners maintain a consistent routine. However, it’s essential to note the weight categories and ensure you’re giving your dog the correct dosage based on their current weight. This aspect underscores the importance of monitoring your dog’s weight and possibly adjusting the dose as they grow or their weight changes.


Safety Profile

The safety of any medication is a paramount concern for pet owners. Both Simparica and NexGard have undergone extensive testing and are generally well-tolerated by most dogs. The most common side effects are mild and include gastrointestinal upset such as vomiting or diarrhea. Rarely, both medications have been associated with neurological side effects, particularly in dogs with a history of seizures.

It’s crucial to discuss any potential risks with your veterinarian, especially if your dog has a history of seizures or other health issues. The safety profiles of Simparica and NexGard are closely matched, and the decision often comes down to individual health considerations and veterinarian advice.


Cost Comparison

When it comes to cost, Simparica and NexGard have almost the same price ranges, with slight variations depending on the retailer or purchase plan. Both are premium products, reflecting their high efficacy and convenience. Buying in bulk or opting for subscription services can offer savings, making both treatments more cost-effective over time.

If you’re buying from Chewy, here’s a quick look at their prices for Simparica:

  • 3 Chewable Tablets: $22.66 for each tablet
  • 6 Chewable Tablets: $21.42 for each tablet
  • 12 Chewable Tablets: $21.41 for each tablet

On the other hand, for Nexgard, here’s a quick look at the price as of the time of writing this article:

  • 1 Chewable Tablet: $31.09 for each tablet
  • 3 Chewable Tablets: $26.97 for each tablet
  • 6 Chewable Tablets: $24.5 for each tablet
  • 12 Chewable Tablets: $24.49

Given the minor differences in price and the potential for savings through smart shopping strategies, cost may not be the primary deciding factor for most pet owners. Instead, efficacy, safety, and convenience are likely to be more influential in making a choice.

WINNER: Simparica 

Taste and Palatability

A crucial yet often overlooked aspect of choosing the right medication is its taste and how eagerly your dog will accept it. Simparica and NexGard tackle this by offering flavors that cater to canine preferences, but with a slight twist in their approach. Simparica comes in a liver-flavored chew, while NexGard is known for its beef flavor. This distinction might not seem significant, but it can make all the difference to a picky eater.

Dogs favor both flavors, indicating that the manufacturers have put thought into ensuring medication time is as stress-free as possible for both pets and their owners. The choice between a liver or beef flavor could come down to your dog’s personal taste, making the palatability of these medications a potential deciding factor for some.


See related topic: NexGard vs Frontline

FAQs: Comparing Simparica vs Nexgard

What are the key differences in efficacy between Simparica and Nexgard?

Simparica and Nexgard both effectively treat and prevent flea and tick infestations in dogs, but they may vary in the duration of effectiveness and the specific ticks they target. While both start killing fleas within hours, Simparica is has an edge for its ability to act against a broader range of tick species over a full month.

Are there any notable safety concerns with either product?

Both products are generally safe for the intended breeds and sizes when used as directed. However, like all medications, they can have side effects. It’s essential to monitor your pet for any adverse reactions and consult with a vet, especially if your dog is pregnant, nursing, or has a history of seizures.

How do the administration methods of Simparica and Nexgard compare?

Both Simparica and Nexgard are for oral adminitsration once a month, making them convenient options for pet owners. The choice between them may come down to your dog’s preference for their taste or any specific dietary restrictions, as some formulations may differ in their ingredients.

How do Simparica and Nexgard differ in the duration of their protection?

Simparica and Nexgard both offer month-long protection from fleas and ticks, but Simparica has shown effectiveness in some studies to start working slightly faster. Both require monthly dosing for continuous protection, emphasizing the importance of adhering to a regular treatment schedule to maintain efficacy.

Can you use Simparica and Nexgard all breeds and sizes of dogs?

Yes, both Simparica and Nexgard are for use in various breeds and sizes of dogs, with specific dosing based on the dog’s weight. However, it’s crucial to consult with a veterinarian before starting treatment, especially for breeds known to be sensitive to certain medications, to ensure the chosen product is appropriate for your dog’s specific health profile and size.

So, Which One Should You Choose?

Deciding between Simparica and NexGard can feel like a tough call. Both products offer robust protection against fleas and ticks, ensuring your furry friend can enjoy their days free from the annoyance and danger of these parasites. In our Simparica vs NexGard comparison, we delved into the specifics of each medication, from their efficacy against different species to their safety profiles and cost-effectiveness.

Simparica edged out slightly in terms of its rapid action and its broader spectrum against tick species, including the Gulf Coast tick. This makes it a strong contender, especially for those in areas where a wide variety of tick species is a concern. On the other hand, NexGard remains a highly reliable and popular choice, loved by dogs and their owners for its effectiveness and ease of use.

Ultimately, the decision comes down to your dog’s specific needs, lifestyle, and any health considerations they may have. It’s also essential to have a conversation with your veterinarian, who can provide personalized advice based on their knowledge of your dog and the local prevalence of fleas and ticks.


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