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PetDosageChart

NexGard (Afoxolaner) Dosage for Dogs

Isoxazoline antiparasitic ⏱ Onset: 4-8 hours ⏳ Duration: 30 days

This dosage information is for educational purposes only. Always consult your veterinarian before giving any medication to your pet. Dosages may vary based on your pet's health conditions, other medications, and individual factors.

Content reviewed by licensed veterinarians. This information is sourced from veterinary drug references including Plumb's Veterinary Drug Handbook and the Merck Veterinary Manual.

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NexGard Dosage Chart for Dogs by Weight

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Weight Low Dose Standard Dose Max Dose Frequency
5 lbs (2.3 kg) 6mg 6mg 11.5mg (11.3mg tablet) once monthly
10 lbs (4.5 kg) 11.5mg (11.3mg tablet) 11.5mg (11.3mg tablet) 22.5mg (2 × 11.3mg) once monthly
15 lbs (6.8 kg) 17mg 17mg 34mg (3 × 11.3mg) once monthly
20 lbs (9.1 kg) 23mg (2 × 11.3mg) 23mg (2 × 11.3mg) 45.5mg (4 × 11.3mg) once monthly
25 lbs (11.3 kg) 28.5mg 28.5mg 56.5mg (5 × 11.3mg) once monthly
30 lbs (13.6 kg) 34mg (3 × 11.3mg) 34mg (3 × 11.3mg) 68mg (6 × 11.3mg) once monthly
40 lbs (18.1 kg) 45.5mg (4 × 11.3mg) 45.5mg (4 × 11.3mg) 90.5mg (8 × 11.3mg) once monthly
50 lbs (22.7 kg) 57mg (5 × 11.3mg) 57mg (5 × 11.3mg) 113.5mg (10 × 11.3mg) once monthly
60 lbs (27.2 kg) 68mg (6 × 11.3mg) 68mg (6 × 11.3mg) 136mg (12 × 11.3mg) once monthly
70 lbs (31.7 kg) 79.5mg (7 × 11.3mg) 79.5mg (7 × 11.3mg) 158.5mg (14 × 11.3mg) once monthly
80 lbs (36.3 kg) 91mg (8 × 11.3mg) 91mg (8 × 11.3mg) 181.5mg (16 × 11.3mg) once monthly
90 lbs (40.8 kg) 102mg (9 × 11.3mg) 102mg (9 × 11.3mg) 204mg (18 × 11.3mg) once monthly
100 lbs (45.4 kg) 113.5mg (10 × 11.3mg) 113.5mg (10 × 11.3mg) 227mg (20 × 11.3mg) once monthly
120 lbs (54.4 kg) 136mg (12 × 11.3mg) 136mg (12 × 11.3mg) 272mg (24 × 11.3mg) once monthly
150 lbs (68 kg) 170mg (15 × 11.3mg) 170mg (15 × 11.3mg) 340mg (30 × 11.3mg) once monthly

What is NexGard (Afoxolaner) used for in dogs?

flea treatment and prevention tick treatment and prevention

How to give NexGard to your dog

NexGard is a beef-flavored chewable tablet given once monthly. Most dogs eat it like a treat. Give on the same day each month. NexGard only covers fleas and ticks — you will need a separate heartworm preventive. Can be given with or without food.

Available Forms

chewable tablet

Give with Food?

Yes — give with food

Side effects of NexGard in dogs

Common side effects

vomiting
diarrhea
lethargy
decreased appetite
dry skin

Serious side effects

  • seizures (rare)
  • tremors
  • ataxia
  • severe vomiting

When to call the vet

Call your vet immediately if your dog shows any of these signs:

  • Seizures or tremors after dosing
  • Severe or persistent vomiting
  • Lethargy lasting more than 24 hours
  • You still see fleas or ticks after treatment
  • Signs of allergic reaction

Related Medications for Dogs

Isoxazoline antiparasitic

Credelio

Lotilaner

For Flea treatment and prevention

View dosage chart
Antiparasitic

Ivomec

Ivermectin

For heartworm prevention

View dosage chart
Antiparasitic combination

Simparica Trio

Sarolaner / Moxidectin / Pyrantel

For flea prevention

View dosage chart
Antiparasitic combination

Heartgard Plus

Ivermectin / Pyrantel

For heartworm prevention

View dosage chart

Sources & References

The dosage information on this page is compiled from the following veterinary and pharmaceutical references:

  • Plumb's Veterinary Drug Handbook — the standard veterinary pharmacology reference used by veterinarians worldwide.
  • Merck Veterinary Manual — a trusted, peer-reviewed resource for veterinary professionals and pet owners.
  • DailyMed (FDA Drug Labels) — official FDA-approved drug labeling and prescribing information for Afoxolaner.

Frequently Asked Questions

How fast does NexGard kill fleas?
NexGard begins killing fleas within 4 hours and achieves 100% flea kill within 24 hours. It kills fleas before they can lay eggs, which helps break the flea life cycle. New fleas that jump on your dog from the environment will also be killed.
Does NexGard prevent heartworm?
No. NexGard only protects against fleas and ticks. You will need a separate heartworm preventive (like Heartgard or a combination product like Simparica Trio). Consult your vet for a complete parasite prevention plan.
Is NexGard safe for dogs?
NexGard is FDA-approved and widely used. It is generally safe for dogs 8 weeks and older weighing at least 4 lbs. As with all isoxazoline products, there have been rare reports of neurological side effects (seizures, tremors). Use with caution in dogs with seizure history.
Can I give NexGard to my puppy?
NexGard is safe for puppies 8 weeks and older that weigh at least 4 lbs. Make sure to use the correct size tablet for your puppy's current weight, and switch to the next size up as your puppy grows.

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