NexGard vs Frontline: what's the difference?
How NexGard and Frontline 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 | Frontline | |
|---|---|---|
| Generic name | Afoxolaner | Fipronil |
| Brand names | NexGard, NexGard Plus, NexGard Spectra | Frontline, PetArmor, Parastar |
| For | Dogs | Dogs and cats |
| Prescription | Prescription | Over the counter (ask your vet first) |
| Used for | A monthly chew that kills fleas and ticks in dogs and helps prevent Lyme disease. [1] | A topical that kills fleas, ticks and chewing lice in dogs and cats. [2] |
| How it works | It spreads through the dog's body, and fleas and ticks die after biting. [1] | It disrupts the nervous system of insects and ticks. [2] |
| Common side effects | Very few in most dogs. Vomiting and diarrhea can happen. [1] | Uncommon. Temporary irritation at the application spot. [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] | Not for puppies or kittens under 8 weeks, or for rabbits. Use the right product for your pet's species and weight. [2] |
| Full guide | NexGard guide | Frontline guide |
Key differences
- They aren't made for the same animals: NexGard is for dogs; Frontline is for dogs and cats.
- How you get them differs: NexGard is prescription; Frontline is over the counter.
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 Frontline is common, but do it only with your vet's plan.
Common questions
What is the difference between NexGard and Frontline?
NexGard is a prescription chew for fleas and ticks in dogs; Frontline is an over-the-counter topical for dogs and cats.
Is NexGard better than Frontline?
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 Frontline 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 Frontline need a prescription?
NexGard: Yes. It needs a prescription from a veterinarian. Frontline: Many forms are sold without a prescription. Still, check with your vet first. Pet doses and safe products are not the same as for people.
Related
This page is general information for planning, not veterinary advice. Talk to your vet about your own pet.