Afoxolaner Dosage Calculator For Dogs
Calculate the minimum recommended Afoxolaner (NexGard®) dose and find the appropriate chewable tablet size based on your dog’s weight.
Minimum Target Dose
Recommended NexGard® Tablet Strength
Dog Weight
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Afoxolaner (NexGard®) is a veterinarian-prescribed, beef-flavoured chewable tablets that contains the active ingredient afoxolaner Dosage For Dogs to protect dogs from fleas and ticks. Afoxolaner is an FDA-approved oral medication that is effective at killing ticks (several species) before they can cause infestations and at killing fleas. Fleas and ticks are among the most common parasites that dogs, cats, and humans can share, and veterinary organizations like the Companion Animal Parasite Council (CAPC) advise year-round parasite control.
It is crucial to know the right afoxolaner dosage for dogs to ensure their safety and effectiveness. NexGard chewables are available in several different weight-based strengths with a minimum dose of 1.14 mg/lb (2.5 mg/kg) body weight. Vets don’t usually determine the exact dose for each dog but rather choose the chewable tablet based on the dog’s weight range.
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Afoxolaner Dosage is approved in dogs and puppies 8 weeks of age and 4 lb (1.8 kg), or more. It treats and prevents flea infestation, and kills a variety of important tick species; it can also be used as part of a wider treatment regime for flea allergy dermatitis (FAD). This chewable formulation is very convenient for most dogs to take on a monthly basis and ensures protection against external parasites all year round.
In this guide, you’ll find the recommended afoxolaner dosage by weight, how the NexGard dosing was calculated, dosage charts for dogs in pounds and kilograms, safety considerations, potential side effects and answers to some of the most frequently asked questions to help ensure your dog receives the right protection each month.
Important Safety Note: Afoxolaner is in the isoxazoline group of drugs. Drugs in this class are generally safe and effective when used as directed; however, rare neurologic side effects have been reported, such as tremors, loss of coordination (ataxia) and seizures. The use of extra precautions is warranted for dogs that have a history of seizures or neurological disorders and if there is any concern, it should be discussed with the veterinarian prior to treatment.
Key Takeaways
- NexGard® contains the active ingredient Afoxolaner which is a chewable medication that treats flea infestations and ticks when given once a month.
- It is fast acting against fleas, and prevents flea infestation, flea allergy dermatitis (FAD) and transmission of flea-borne parasites.
- Afoxolaner dose for dogs works in a variety of common tick species to decrease the risk of tick-borne diseases such as Lyme.
- NexGard chewables are dosed based on body weight and have a minimum dose rate of 1.14 mg/lb (2.5 mg/kg).
- There are some products containing NexGard that will have added ingredients for heartworm and intestinal parasites.
- NexGard dosage for dogs is approved for dogs and puppies 8 weeks of age and older that weigh at least 4 lbs (1.8 kg).
- Afoxolaner is in a class of drugs called isoxazolines; dogs with a history of seizures or nervous system disorders should be seen by a veterinarian before using afoxolaner.
- Afoxolaner has been tested and has been demonstrated to be safe and effective when used as directed in studies and by veterinarians.
- NexGard should be administered according to the directions of your veterinarian and is available by veterinary prescription only.
Afoxolaner (NexGard) Dosage Chart for Dogs
| Dog Weight (lbs) | Dog Weight (kg) | Recommended NexGard Tablet | Afoxolaner Strength |
|---|---|---|---|
| 4.0 – 10.0 lbs | 1.8 – 4.5 kg | Small Dog Chew | 11.3 mg |
| 10.1 – 24.0 lbs | 4.6 – 11.0 kg | Medium Dog Chew | 28.3 mg |
| 24.1 – 60.0 lbs | 11.1 – 27.0 kg | Large Dog Chew | 68.0 mg |
| 60.1 – 121.0 lbs | 27.1 – 55.0 kg | Extra-Large Dog Chew | 136.0 mg |
| Over 121 lbs | Over 55 kg | Combination of tablets as directed by a veterinarian | Varies |
Minimum Dosage Formula
- Kilograms: Weight (kg) × 2.5 = Target Afoxolaner Dose (mg)
- Pounds: Weight (lb) × 1.14 = Target Afoxolaner Dose (mg)
Example Calculations
| Dog Weight | Calculated Minimum Dose |
|---|---|
| 5 kg (11 lbs) | 12.5 mg |
| 10 kg (22 lbs) | 25 mg |
| 20 kg (44 lbs) | 50 mg |
| 30 kg (66 lbs) | 75 mg |
| 50 kg (110 lbs) | 125 mg |
Note: Afoxolaner Dosage For Dogs By Weight is typically administered as a once-monthly chewable tablet. Dogs receive the tablet that matches their weight range rather than an exact calculated milligram dose. For dogs weighing more than 121 lbs (55 kg), veterinarians generally use an appropriate combination of tablet strengths. Always follow your veterinarian’s recommendations and the product label.
What Is Afoxolaner?
Afoxolaner For Dogs is an antiparasitic drug and is the active ingredient in NexGard®, an FDA approved oral chewable treatment for dogs. Treats and prevents flea infestation, controls certain species of ticks, and prevents Lyme disease by killing the infected ticks before they can transmit the disease. NexGard is a beef flavoured monthly chewable tablet for dogs and puppies 8 weeks or older, 4 lb (1.8 kg) or more, manufactured by Boehringer Ingelheim Animal Health.
Once eaten by a dog, afoxolaner is absorbed into the bloodstream and carried throughout the body. Fleas and ticks are destroyed by ingesting the drug when they feed on the dog’s blood, which will help protect the dog from infestations and from the diseases that these parasites can transmit. Given the many health risks that fleas and ticks pose to pets and people, veterinary experts like the Companion Animal Parasite Council (CAPC) and the Canadian Parasitology Expert Panel (CPEP) recommend regular flea and tick control.
Veterinarians also may use afoxolaner extra-label (off-label) for sarcoptic mange, demodectic mange, cutaneous myiasis, ear mites and sand fly infestations in dogs. It has also been tried off label in cats for ear mites and birds for peacock louse. On February 2026, the U.S. Food and Drug Administration (FDA) approved the use of NexGard (afoxolaner) to treat New World screwworm infestations in dogs and cats.
Afoxolaner is in a group of drugs called isoxazolines. Research and clinical experience indicate it is generally safe and effective when used according to its instructions, but the FDA has reported rare neurological adverse events (scientific terminology for bad side effects) associated with isoxazolines, such as tremors, loss of co-ordination (ataxia) and seizures. Because of this, veterinarians might prefer to exercise extra care in dogs who have previously had seizures or other neurological problems.
How Afoxolaner Works and What It’s Used For
Afoxolaner medication is an oral anti-parasitic agent that helps prevent dogs from getting fleas and ticks. Your dog eats the chewable tablet, and the medicine is absorbed into the bloodstream and goes to the body. Fleas and ticks ingest afoxolaner when they feed on the dog’s blood, and it disrupts their nervous systems, causing paralysis and death.
Afoxolaner works quickly, one of the reasons it is widely used. It starts killing ticks about 12 hours after exposure and killing fleas about 4 hours after exposure. A treated dog may still shed fleas for a short period of time, particularly when it’s an infestation at home, but the new fleas will die after feeding. The infestation slowly decreases as flea reproduction is disrupted.
Main Uses of Afoxolaner
The main use for Afoxolaner is:
- How to treat and prevent flea infestations
- Treating and controlling tick infestation
- Minimizing risk of tick-borne diseases including Lyme disease
- Protects against parasites in dogs for 30 days.
Tick Species Controlled
The type of ticks controlled may differ from area to area and include:
- Black-legged (deer) tick (Ixodes scapularis)
- Dog tick: American dog tick (Dermacentor variabilis)
- Lone star tick, Amblyomma americanum.
- Brown dog tick (Rhipicephalus sanguineus) is considered one of the most important diseases affecting dogs.
- Asian longhorned tick (Haemaphysalis longicornis)
- Marsh tick (Dermacentor reticulatus)
- Castor bean tick (Ixodes ricinus)
- Tick: Paralysis tick (Ixodes holocyclus)
- Bush tick (Haemaphysalis longicornis)
Afoxolaner is also sold in NexGard Products.
Afoxolaner is an active ingredient in several NexGard products:
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- NexGard Chewables – Only contains afoxolaner, and is effective for flea and tick control.
- NexGard PLUS Chewables – For protection against fleas, ticks, heartworms, roundworms, and hookworms (has afoxolaner, moxidectin and pyrantel).
Off-Label Uses
Afoxolaner may be prescribed by a veterinarian for other uses not specified in the label, such as:
- Demodectic mange
- Sarcoptic mange
- Ear mite infestations
This is referred to as an ‘off-label’ use, which is where the medicine is used for a condition or in a way that is not actually stated on the label but for which there is veterinary clinical judgment.
Administration Guidelines
Afoxolaner drug for dogs is provided as a tasty chew that’s taken orally and is generally administered once a month. May be taken with or without food, but must be eaten to be effective. Year round monthly treatments are usually necessary for year-round flea and tick protection. Dosing should always be based on weight and your veterinarian should be consulted before using in pregnant, lactating and medically compromised dogs.
How Do I Give Afoxolaner to My Dog?
Afoxolaner is given as a flavored chewable tablet, and must only be given as directed by your veterinarian. Afoxolaner in NexGard is available in various strengths based on the size of the dog, and is normally administered once a month to provide ongoing protection against fleas and ticks.
The chewable tablet can be either fed with or without food and water for convenient administration for most dogs. Once you’ve given your dog the pill, make sure your dog eats all of it. It is important for pet owners to watch their dog for a few minutes after giving it the chew to ensure they do not drop any part of the chew, spit it out or lose it.
Administration Tips
- Administer chewable tablet orally once a month.
- Apply the proper strength according to the weight of your dog.
- The medication can be given with or without food.
- Be sure your dog eats the whole chewable tablet.
- Always take into account all veterinary dosing guidelines.
What If My Dog Vomits After Afoxolaner?
If your dog vomits within 2 hours after giving afoxolaner, give him another full dose as it may not have been completely absorbed. If needed for future doses, feeding the chew with food may minimize the risk for vomiting.
Year-Round Protection
Afoxolaner treatment can be started at any time of the year for flea and tick control. In climates with year around fleas, monthly flea treatments are suggested without interruption to help keep the fleas suppressed and prevent reinfestations. Ideally, all pets in the home should be treated with the proper pet parasite control products.
Always use the product according to the label and your veterinarian’s advice for effective and safe use, and for continuous prevention of parasites.
Are There Any Potential Side Effects From Afoxolaner?
When used according to the directions on the product label or veterinarian’s instructions, afoxolaner is generally very well-tolerated by most dogs. Most dogs don’t have any side effects, and those that do typically have mild and short-lived adverse reactions. As with all medicines however side effects and serious reactions may occur.
Side effects of afoxolaner include diarrhea, loss of appetite, and vomiting.
Common side effects are:
- Vomiting (either blood or not)
- Diarrhea (bloody or not)
- Dry or flaky skin
- Itching
- Lethargy (low energy)
- Loss of appetite or appetite loss (anorexia)
The reactions are normally rare and may happen in as few as 1–10% of dogs. See your veterinarian if the symptoms continue or get worse.
Adverse Effects and Neurotoxic Reactions
More severe side effects can occur, but are uncommon. Afoxolaner is part of the isoxazoline family of drugs, and some dogs may experience neurological side effects.
Neurological signs may include:
- Coordinated movement isn’t as well controlled as usual (ataxia)
- Muscle tremors
- Seizures
If your dog has seizures or tremors, or any other serious reaction after taking afoxolaner, stop the use immediately and get veterinary help right away.
Risk Factors and Precautions
Afoxolaner should not be used in:
- Dogs known to be allergic or hypersensitive to afoxolaner.
- Puppies under 8 weeks old, unless otherwise instructed by a veterinarian
- Dogs that weigh less than 4 lbs (1.8 kg) unless directed by a veterinarian.
Caution should be used when applying afoxolaner to:
- Dogs that have had a seizure or neurological disease previously.
- Breeding dogs
- Pregnant dogs
- Lactating (nursing) dogs
Safety of afoxolaner in breeding animals, pregnant animals and lactating animals has not been completely assessed.
Side Effect Reports and what they mean to you.
It’s important to keep in mind that side-effect lists are meant to be extensive. In clinical studies, all symptoms in the dogs participating in the study are reported, even if the medication is not responsible for the symptoms. Also, side effects reported by veterinarians and pet owners after afoxolaner has been marketed are not necessarily attributed to the use of afoxolaner.
Overall, scientific evidence and clinical experience indicate that afoxolaner is safe and effective for most dogs when used as directed. If any unusual symptoms occur after administering, seek advice from your veterinarian on what to do next.
Are There Any Drug Interactions That I Should Be Aware Of?
There are no known or reported significant interactions with afoxolaner (NexGard) at this time. A limited number of studies showed that there are generally no known interaction concerns with the use of afoxolaner with many common veterinary products such as vaccines or anesthetic agents. There is, however, limited research on possible interactions, and new information may become available as further research is done.
It’s important to tell your veterinarian about all medicines and products your dog is getting before starting treatment with afoxolaner.
such as:
- Prescription medications
- Over-the-counter products
- Vitamins
- Nutritional supplements
- Herbal remedies
- Preventive medications
A complete medication history will allow your veterinarian to determine if afoxolaner is the right medication for your dog’s treatment and health.
Afoxolaner is not known to cause any withdrawal effects.
Most dogs do not need any special routine lab work performed while on afoxolaner. Your veterinarian, however, might suggest additional tests to make sure that the drug is working and that it’s not having any side effects.
Monitor your dog during use of afoxolaner for any unusual symptoms or side effects, including:
- Vomiting
- Diarrhea
- Lethargy
- Loss of appetite
- Skin changes
- Neurological symptoms like shaking, uncoordination or convulsions
Stop the medication and contact your veterinarian immediately if any adverse reactions are noticed. Your veterinarian is always your best choice for communicating about safe and effective use of afoxolaner.
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FAQs
What does afoxolaner dosage do for dogs?
Afoxolaner treats and prevents flea infestations and controls tick infestations on dogs. It is the active ingredient in NexGard; it is effective against parasites after they feed on the dog and reduces the risk of flea and tick-borne diseases.
How often do you have to use afoxolaner?
Afoxolaner is usually applied once a month. For year-round flea and tick protection, it is recommended to be administered monthly.
Is it okay to administer afoxolaner dose with food?
Yes. Afoxolaner chewable tablets can be given with or without food. If the dog does vomit after being given, however, future administration with food may help to increase tolerance.
If I forget to take one dose, what should I do?
In case of missed dose, repeat as soon as remembered and restart a new monthly dose at the date of the missed dose. Do not give two doses at the same time to make up for a missed dose.
If a dog vomits following administration of afoxolaner, what should I do?
If vomiting occurs within 2 hours of giving, repeat the full dose as it may not have been fully absorbed. If your dog continues to vomit or you are unsure of his response, call your vet.
What is the storage for afoxolaner medication?
Afoxolaner products may be kept at room temperature (less than 86°F/30°C). Store the drug in a cool, dry area and out of the way of high heat and moisture.
Is afoxolaner safe for puppies?
Afoxolaner treats puppies 8 weeks old and over 4 pounds (1.8 kg) in weight. Only administer the medication to puppies under this age if advised by a veterinarian.
What if someone overdoses or has an emergency?
If your dog seems to be having an adverse reaction, or you think it’s an overdose, contact your veterinarian right away. Remember, if your regular vet is not available, then turn to an emergency veterinary facility. Have a record of the product that was used, your dog’s weight, the dosage that was given, and any symptoms you saw.
Final Thoughts
Afoxolaner Dosage For Dogs is a popular and highly effective flea and tick treatment which offers convenient monthly protection for dogs. When used as directed by a veterinarian, it is effective at killing fleas, controlling several species of ticks and helps prevent disease caused by parasites, as the active ingredient in NexGard.
Afoxolaner is very well tolerated by most dogs and the flavored, chewable form makes it easy for pet owners to give it to their dog on a monthly basis. To ensure safe and effective management of parasites, however, the correct weight-based dosage, treatment schedule and monitoring for side effects is important.
When deciding whether to use afoxolaner on your dog, talk with your vet about which product to use and the dosage. If used correctly, year-round protection from parasites can help keep your dog healthy, happy and free from fleas, ticks and potentially disease.
