Afoxolaner for Dogs and Cats
Vet-reviewed by Dr. Pippa Elliott, BVMS MRCVS ·
What is Afoxolaner for Dogs and Cats
Overview
Afoxolaner is a systemic insecticide and acaricide formulated for oral administration in dogs. After being consumed, it is absorbed into the bloodstream, where fleas and ticks ingest it during feeding. Because it works internally, its effectiveness is not reduced by bathing or swimming.
This medication is best known under the NexGard brand and is widely used in veterinary medicine due to its rapid onset of action and reliable monthly protection. It is effective against multiple tick species, including those associated with Lyme disease, and has demonstrated excellent speed of kill against adult fleas.
Explore more parasite-control medications in our Parasites section.
What Is Afoxolaner for Dogs and Cats Used For
| Condition | Notes |
|---|---|
| Fleas | Kills adult fleas quickly, preventing egg laying. |
| Ticks | Effective against multiple species, including black-legged ticks. |
| Demodectic mange | Used off-label; shown effective in cases of generalized demodicosis. |
| Sarcoptic mange | Used off-label; improves symptoms and clears mites. |
| Flea allergy dermatitis support | Helps eliminate active flea bites that trigger irritation. |
How Afoxolaner for Dogs and Cats Works
Afoxolaner interferes with the nervous system of fleas and ticks by blocking ligand-gated chloride channels, specifically GABA receptors. This causes uncontrolled nerve stimulation that leads to parasite paralysis and death.Because it circulates in the dog’s bloodstream, parasites must bite to be affected, but once they do, death occurs rapidly.
Drug Facts
Afoxolaner is a systemic flea and tick control medication given orally once monthly. It begins working within hours and maintains effectiveness for a full 30 days.
Common Brands
NexGard
Drug Class
Isoxazoline parasiticide
Substance Classification
Not a controlled medication
Generic Status
Branded formulations only
Availability
Prescription
Afoxolaner for Dogs and Cats Dosage Forms
Afoxolaner is available as a chewable oral tablet for dogs. Tablets come in different strengths based on body weight and are flavored for easier administration.
Chewable Tablets (6-pack)
| Group | Price as low as | Price per unit |
|---|---|---|
| Small dog (4–10 lbs) | $120.00 | $20.00 |
| Medium dog (10–24 lbs) | $125.00 | $20.00 |
| Large dog (24–60 lbs) | $130.00 | $21.00 |
| Extra-large (>60 lbs) | $135.00 | $22.00 |
Typical Dosing For Afoxolaner for Dogs and Cats
Afoxolaner is given once monthly, with the tablet strength chosen based on the dog’s weight. It should be administered with food for optimal absorption.
Oral Dosage
| Group | Typical Dose | Notes |
|---|---|---|
| Dogs (all sizes) | 2.5 mg/kg orally once monthly | Standard label dose. |
| Demodex cases (off-label) | 2.5 mg/kg every 2–4 weeks | Used until mites clear and hair regrowth occurs. |
| Sarcoptic mange (off-label) | 2.5 mg/kg monthly × 2–3 months | Reduces clinical signs and mite counts. |
Afoxolaner is not labeled for cats.
Risks and Warnings for Afoxolaner for Dogs and Cats
Afoxolaner is considered safe for most dogs, but as with other isoxazolines, neurological side effects are possible, especially in dogs with a history of seizures.
Observed Side Effects
- Vomiting
- Diarrhea
- Lethargy
- Itching
- Loss of appetite
These reactions are generally mild and temporary.
Neurologic Concerns
Afoxolaner may cause:
- Tremors
- Ataxia
- Seizures
These events are rare but have been reported, particularly in dogs predisposed to neurologic disease.
Use in Sensitive Populations
- Safe for puppies 8 weeks and older weighing at least 4 lbs.
- Not evaluated in breeding, pregnant, or lactating dogs.
Afoxolaner for Dogs and Cats Warnings and Precautions
Use afoxolaner carefully and follow veterinary guidance:
- Do not use in dogs with a history of seizures unless cleared by a veterinarian.
- Use with caution in dogs with existing neurologic disorders.
- Store tablets safely away from children and other animals.
- Give the full monthly dose for consistent protection.
- Report any persistent vomiting, tremors, or unusual behavior to your veterinarian.
Disclaimer: This information is for educational purposes only and should not replace professional veterinary advice. Always consult your veterinarian before using or combining any medications for your pet.
Frequently Asked Questions (FAQ)
How fast does afoxolaner start working?
It begins killing fleas within hours of ingestion.
Does afoxolaner require the parasite to bite?
Yes. Fleas and ticks must feed to ingest the medication.
Can afoxolaner be given with other medications?
Typically yes, but always check with your veterinarian to avoid interactions.
Is afoxolaner safe for dogs with allergies?
Most dogs tolerate it well, but monitor for stomach upset or itching after the first dose.
Does afoxolaner kill flea eggs?
It kills adult fleas before they can lay eggs, stopping the flea life cycle.
Related Medications & Supplements
Dogs treated for fleas and ticks may also use other parasite control medications for broader protection or faster relief. These related treatments are commonly used alongside products like afoxolaner.
- Fluralaner - long lasting oral flea and tick medication
- Selamectin - topical parasite preventive covering fleas, mites, and some worms
- Nitenpyram - fast acting oral flea treatment providing rapid kill
- Moxidectin - topical or injectable broad spectrum parasite control
- Permethrin - topical flea and tick preventive used in combination products
References
- Chávez, F. (2016). Case Report of Afoxolaner Treatment for Canine Demodicosis in Four Dogs Naturally Infected with Demodex Canis. Available at: https://jarvm.com/articles/Vol14Iss2/Vol14%20Iss2%20Chavez.pdf
- Dodds, W. J. & Kimball, J. P. (2021). Updated Summary on Use and Safety of Flea and Tick Preventives for Animals. Journal of Veterinary Medicine & Surgery, 5 (S2): 005. Available at: https://www.primescholars.com/articles/updated-summary-on-use-and-safety-of-flea-and-tick-preventives-for-animals-94239.html
- Drag, M., Tielemans, E. & Mitchell, E. (2022). Safety of oral afoxolaner formulated with or without milbemycin oxime in homozygous MDR1‐deficient collie dogs. Journal of Veterinary Pharmacology and Therapeutics, 45 (4), pp. 373–379. doi: 10.1111/jvp.13064.
- Machado, M. A., Campos, D. R., Lopes, N. L., et al. (2019). Efficacy of afoxolaner in the flea control in experimentally infested cats. Revista Brasileira de Parasitologia Veterinária, 28 (4), pp. eS1984-29612019064. doi: 10.1590/S1984-29612019064.
- Panarese, R., Iatta, R., Mendoza‑Roldan, J. A., Zatelli, A., Beugnet, F. & Otranto, D. (2021). Efficacy of afoxolaner (NexGard®) in preventing the transmission of Leishmania infantum and Dirofilaria immitis to sheltered dogs in a highly endemic area. Parasites & Vectors, 14, p. 381. doi: 10.1186/s13071-021-04883-3.
- Pfister, K. & Armstrong, R. (2016). Systemically and cutaneously distributed ectoparasiticides: a review of the efficacy against ticks and fleas on dogs. Parasites & Vectors, 9, p. 436. doi: 10.1186/s13071-016-1719-7.
- U.S. Food and Drug Administration. (2013). FREEDOM OF INFORMATION SUMMARY ORIGINAL NEW ANIMAL DRUG APPLICATION NADA 141-406 NEXGARD Afoxolaner Chewable Tablet Dogs. Available at: https://animaldrugsatfda.fda.gov/adafda/app/search/public/document/downloadFoi/14165
- Walden, L. A. (2016). Effectiveness of Fluralaner and Afoxolaner Against Flea Infestations in Dogs. dvm360, 5 August. Available at: https://www.dvm360.com/view/effectiveness-of-fluralaner-and-afoxolaner-against-flea-infestations-in-dogs
Editor
The Webvet Editorial Team is a collective of seasoned pet-care journalists, veterinary content specialists, and industry editors dedicated to delivering accurate, trustworthy, and compassionate pet health information. With decades of combined experience across veterinary reporting, pet wellness education, and consumer product research, our team works closely with veterinarians and certified pet experts to ensure every article is both evidence-based and easy to understand.
Veterinarian · BVMS MRCVS
Dr. Pippa Elliott, BVMS, MRCVS, is a veterinarian with nearly 30 years of experience in companion animal practice. Dr. Elliott earned her Bachelor of Veterinary Medicine and Surgery from the University of Glasgow. She was also designated a Member of the Royal College of Veterinary Surgeons. Married with 2 grown-up kids, Dr. Elliott has a naughty Puggle named Poggle, 3 cats and a bearded dragon.
