Afoxolaner

Indications

NexGard ® kills adult fleas and is indicated for the treatment and prevention of flea infestations (Ctenocephalides felis) , and the treatment and control of Ixodes scapularis (black-legged tick ) , Dermacentor variabilis (American dog tick ) , Amblyomma americanum (lone star tick) , Amblyomma maculatum (Gulf Coast tick), Rhipicephalus sanguineus (brown dog tick ) , and Haemaphysalis longicornis (longhorned tick) infestations in dogs and puppies 8 weeks of age and older, weighing 4 pounds of body weight or greater, for one month. NexGard ® is indicated for the prevention of Borrelia burgdorferi infections as a direct result of killing lxodes scapularis vector ticks.

Dosage and Administration

NexGard ® is given orally once a month, at the minimum dosage of 1.14 mg/lb (2.5 mg/kg). Dosing Schedule: Body Weight Afoxolaner Per Chewable (mg) Chewables Administered 4 to 10 lbs. 11.3 One 10.1 to 24 lbs. 28.3 One 24.1 to 60 lbs. 68 One 60.1 to 121 lbs. 136 One Over 121 lbs. Administer the appropriate combination of chewables NexGard ® can be administered with or without food. Care should be taken that the dog consumes the complete dose, and treated animals should be observed for a few minutes to ensure that part of the dose is not lost or refused. If it is suspected that any of the dose has been lost or if vomiting occurs within two hours of administration, redose with another full dose. If a dose is missed, administer NexGard ® and resume a monthly dosing schedule. Flea Treatment and Prevention: Treatment with NexGard ® may begin at any time of the year. In areas where fleas are common year-round, monthly treatment with NexGard ® should continue the entire year without interruption. To minimize the likelihood of flea reinfestation, it is important to treat all animals within a household with an approved flea control product. Tick Treatment and Control: Treatment with NexGard ® may begin at any time of the year (see

Contraindications

There are no known contraindications for the use of NexGard ® .

Warnings

Not for use in humans. Keep this and all drugs out of the reach of children. In case of accidental ingestion, contact a physician immediately. Keep NexGard ® in a secure location out of reach of dogs, cats, and other animals to prevent accidental ingestion or overdose.

Precautions

Afoxolaner is a member of the isoxazoline class. This class has been associated with neurologic adverse reactions including tremors, ataxia, and seizures. Seizures have been reported in dogs receiving isoxazoline class drugs, even in dogs without a history of seizures. Use with caution in dogs with a history of seizures or neurologic disorders. The safe use of NexGard ® in breeding, pregnant or lactating dogs has not been evaluated.

Adverse Reactions

In a well-controlled US field study, which included a total of 333 households and 615 treated dogs (415 administered afoxolaner; 200 administered active control), no serious adverse reactions were observed with NexGard ® . Over the 90-day study period, all observations of potential adverse reactions were recorded. The most frequent reactions reported at an incidence of > 1% within any of the three months of observations are presented in the following table. The most frequently reported adverse reaction was vomiting. The occurrence of vomiting was generally self-limiting and of short duration and tended to decrease with subsequent doses in both groups. Five treated dogs experienced anorexia during the study, and two of those dogs experienced anorexia with the first dose but not subsequent doses. Table 1: Dogs With Adverse Reactions. Treatment Group Afoxolaner Oral active control N Number of dogs in the afoxolaner treatment group with the identified abnormality. % (n=415) N Number of dogs in the control group with the identified abnormality. % (n=200) Vomiting (with and without blood) 17 4.1 25 12.5 Dry/Flaky Skin 13 3.1 2 1.0 Diarrhea (with and without blood) 13 3.1 7 3.5 Lethargy 7 1.7 4 2.0 Anorexia 5 1.2 9 4.5 In the US field study, one dog with a history of seizures experienced a seizure on the same day after receiving the first dose and on the same day after receiving the second dose of NexGard ® . This dog experienced a third seizure one week after receiving the third dose. The dog remained enrolled and completed the study. Another dog with a history of seizures had a seizure 19 days after the third dose of NexGard ® . The dog remained enrolled and completed the study. A third dog with a history of seizures received NexGard ® and experienced no seizures throughout the study. In a second US field safety and effectiveness study, NexGard ® was administered to 130 dogs with fleas. Adverse reactions included pruritus, diarrhea (with or without blood), vomiting, anorexia, and lethargy. Post-Approval Experience (July 2018): The following adverse events are based on post-approval adverse drug experience reporting. Not all adverse events are reported to FDA/CVM. It is not always possible to reliably estimate the adverse event frequency or establish a causal relationship to product exposure using these data. The following adverse events reported for dogs are listed in decreasing order of reporting frequency for NexGard ® : Vomiting, pruritus, lethargy, diarrhea (with and without blood), anorexia, seizure, hyperactivity/restlessness, panting, erythema, ataxia, dermatitis (including rash, papules), allergic reactions (including hives, swelling), and tremors.

Description

NexGard ® (afoxolaner) is available in four sizes of beef-flavored, soft chewables for oral administration to dogs and puppies according to their weight. Each chewable is formulated to provide a minimum afoxolaner dosage of 1.14 mg/lb (2.5 mg/kg). Afoxolaner has the chemical composition 1-Naphthalenecarboxamide, 4-[5-[3-chloro-5-(trifluoromethyl)-phenyl]-4, 5-dihydro-5-(trifluoromethyl)-3-isoxazolyl]-N-[2-oxo-2-[(2,2,2-trifluoroethyl)amino]ethyl.

Storage

Store at or below 30°C (86°F) with excursions permitted up to 40°C (104°F).

FDA adverse event reports

The FDA Center for Veterinary Medicine publishes the adverse event reports it receives through openFDA. The counts below are the reports naming afoxolaner as an active ingredient for each species this label names, as returned on 2026-09-16, coded by the VeDDRA reaction term the reporter chose. Reactions are counted per report, so one report can appear under several terms.

These are counts, not rates. Reporting is voluntary, the number of animals treated is not known, and a widely used product accumulates reports for that reason alone. A report records that an event followed a dose; it does not establish that the product caused it. The counts say nothing about how one product compares with another.