NexGard vs Simparica: what's the difference?
How NexGard and Simparica compare: what each is for, how it works, side effects and cost, side by side.
Last updated: October 2026 · 2 sources · see sources
Side by side
| NexGard | Simparica | |
|---|---|---|
| Generic name | Afoxolaner | Sarolaner |
| Brand names | NexGard, NexGard Plus, NexGard Spectra | Simparica, Simparica Trio, Revolution Plus |
| For | Dogs | Dogs and cats |
| Prescription | Prescription | Prescription |
| Used for | A monthly chew that kills fleas and ticks in dogs and helps prevent Lyme disease. [1] | Kills fleas and ticks in dogs. Combined products also cover heartworm and worms, and Revolution Plus is made for cats. [2] |
| How it works | It spreads through the dog's body, and fleas and ticks die after biting. [1] | Absorbed into the body; fleas and ticks are killed when they feed. [2] |
| Common side effects | Very few in most dogs. Vomiting and diarrhea can happen. [1] | Vomiting, diarrhea and low appetite. [2] |
| Use with care | An isoxazoline: the FDA has warned of possible tremors, wobbliness and seizures. Not for puppies under 8 weeks or 4 pounds unless your vet says so. [1] | The single-drug Simparica chew is not for cats. An isoxazoline, so use caution in pets with seizures. [2] |
| Full guide | NexGard guide | Simparica guide |
Key differences
- They aren't made for the same animals: NexGard is for dogs; Simparica is for dogs and cats.
Which one is right for my pet?
That is a call for your vet. They weigh your pet's age, weight, other health problems, other medicines and what you can realistically give at home.
Switching from NexGard to Simparica is common, but do it only with your vet's plan.
Common questions
What is the difference between NexGard and Simparica?
Both are chews that kill fleas and ticks in dogs. NexGard is labeled to help prevent Lyme disease; Simparica's combination products also cover heartworm and worms.
Is NexGard better than Simparica?
Neither is better for every pet. Your vet chooses based on your pet's species, age, health history, other medicines and what you can manage at home.
Can my pet take NexGard and Simparica together?
Only if your vet says so. Some medicines in the same family should not be combined, and others are often used together. Always check before adding or switching.
Do NexGard and Simparica need a prescription?
NexGard: Yes. It needs a prescription from a veterinarian. Simparica: Yes. It needs a prescription from a veterinarian.
Related
This page is general information for planning, not veterinary advice. Talk to your vet about your own pet.