Flea and tick medicine for dogs and cats: a guide
Checked against FDA and EPA information: October 2026
Short answer
Flea and tick protection comes as prescription chewables, spot-on treatments and collars. Prescription chewables such as NexGard, Bravecto, Simparica and Credelio come through your vet or a veterinary pharmacy, not a regular pharmacy, while many spot-ons and collars are sold over the counter. Never use a dog product on a cat: permethrin, found in many dog treatments, can kill cats.
The main types of flea and tick protection
- Chewables (isoxazolines)NexGard (afoxolaner), Bravecto (fluralaner), Simparica (sarolaner), Credelio (lotilaner)Prescription: Yes · Regulated by: FDAGiven monthly, or every 12 weeks for Bravecto chewables. Mostly for dogs; some have cat versions.
- Chewables with heartworm preventionSimparica Trio and similar combination productsPrescription: Yes · Regulated by: FDAYour vet tests for heartworm before starting.
- Prescription spot-onsRevolution (selamectin), Bravecto topical (fluralaner)Prescription: Yes · Regulated by: FDAApplied to the skin; versions exist for dogs and for cats.
- Over-the-counter spot-onsProducts containing fipronil (Frontline) or imidacloprid (Advantage)Prescription: No · Regulated by: EPAChoose the product labeled for your pet’s species and weight.
- CollarsSeresto (imidacloprid and flumethrin) and othersPrescription: No · Regulated by: EPAProtection lasts for months; check the fit regularly.
- Permethrin products for dogsMany dog spot-ons and sprays, such as K9 AdvantixPrescription: No · Regulated by: EPADogs only. Permethrin can cause seizures and death in cats.
| Type | Prescription | Regulated by | Notes |
|---|---|---|---|
| Chewables (isoxazolines)NexGard (afoxolaner), Bravecto (fluralaner), Simparica (sarolaner), Credelio (lotilaner) | Yes | FDA | Given monthly, or every 12 weeks for Bravecto chewables. Mostly for dogs; some have cat versions. |
| Chewables with heartworm preventionSimparica Trio and similar combination products | Yes | FDA | Your vet tests for heartworm before starting. |
| Prescription spot-onsRevolution (selamectin), Bravecto topical (fluralaner) | Yes | FDA | Applied to the skin; versions exist for dogs and for cats. |
| Over-the-counter spot-onsProducts containing fipronil (Frontline) or imidacloprid (Advantage) | No | EPA | Choose the product labeled for your pet’s species and weight. |
| CollarsSeresto (imidacloprid and flumethrin) and others | No | EPA | Protection lasts for months; check the fit regularly. |
| Permethrin products for dogsMany dog spot-ons and sprays, such as K9 Advantix | No | EPA | Dogs only. Permethrin can cause seizures and death in cats. |
Why it matters who regulates the product
Oral flea and tick medicines and prescription spot-ons are animal drugs approved by the FDA, which reviews their safety and effectiveness before sale. Many over-the-counter spot-ons and collars are registered as pesticides with the EPA instead. Both are legal, but problems are reported to different agencies: suspected reactions to an FDA-approved product go to the manufacturer or the FDA, and reactions to an EPA-registered product go to the manufacturer or the EPA.
Safety points
- Never use a dog product on a cat. Permethrin, in many dog spot-ons and sprays, can cause tremors, seizures and death in cats, even from close contact with a recently treated dog.
- The FDA has warned that isoxazoline chewables and spot-ons can cause neurologic reactions, including muscle tremors, unsteadiness and seizures, in some dogs and cats. Tell your vet about any history of seizures before starting one.
- Weigh your pet and use the product for that weight band; do not split a product made for a larger animal unless your vet tells you how.
- Buy from your vet, a veterinary pharmacy or a reputable retailer. The EPA has warned about counterfeit flea and tick products sold online.
Where to get prescription flea and tick medicine
Prescription chewables and spot-ons are veterinary products, so a regular pharmacy cannot fill them. Your vet can dispense them, or authorize an online veterinary pharmacy to; look for one that requires a prescription and is accredited, for example through the National Association of Boards of Pharmacy. See which pet medicines a regular pharmacy can fill and our comparison of NexGard and Bravecto.
Prices differ between the clinic, online veterinary pharmacies and manufacturer rebates, so it is worth comparing. Over-the-counter products are often cheaper, and store-brand versions of fipronil and imidacloprid spot-ons contain the same active ingredients as the name brands.
Frequently asked questions
Can I buy NexGard or Bravecto without a prescription?
No. In the US they are prescription products, dispensed by your vet or a veterinary pharmacy with your vet’s authorization.
Can I use my dog’s flea treatment on my cat?
No. Many dog products contain permethrin, which can cause tremors, seizures and death in cats, and doses differ between species. Use only products labeled for cats.
Are flea and tick pills safe?
They are FDA-approved and widely used. The FDA has warned that the isoxazoline class can cause neurologic reactions such as tremors, unsteadiness and seizures in some dogs and cats, so tell your vet about any history of seizures.
Do indoor cats need flea treatment?
Often, yes, because fleas can come indoors on people and other pets. Ask your vet what suits your household.
How often do I give flea and tick medicine?
It depends on the product: most chewables and spot-ons are monthly, Bravecto chewables last 12 weeks, and collars last several months. Many vets recommend year-round protection.