Afoxolaner

What is afoxolaner?

Afoxolaner (NexGard®) is used to treat and prevent flea and tick infestations in dogs. It is also used as a preventive for Lyme disease.

After being ingested by a dog, afoxolaner is distributed throughout the dog’s body. When fleas or ticks bite the dog, they are exposed to the drug and killed during their blood meal. 

Sometimes afoxolaner is used in the treatment of sarcoptic mange, demodectic mange, cutaneous myiasis, ear mite infestations, and sand fly infestations in dogs. It is also occasionally used in cats to treat ear mites and in birds to treat peacock louse. 

When afoxolaner is prescribed in these cases, it is off-label (extra-label). Many drugs are commonly prescribed for off-label use in veterinary medicine. 

“Off label” means the drug is being used in a way that has not been reviewed or approved by the U.S. Food and Drug Administration (FDA) or Health Canada. In these instances, follow your veterinarian’s directions and cautions carefully, as they may be significantly different from those on the label. 

How quickly does afoxolaner kill fleas and ticks? 

After exposure, afoxolaner begins to kill fleas after four hours and ticks after at least 12 hours. Keep in mind that you will likely continue to see fleas on a treated dog for some time, especially if you have a flea infestation in your home. Fleas will continue to hatch and climb onto your dog in search of a blood meal. 

The fleas' death prevents reproduction and new eggs being laid in the home. The more fleas that climb onto the dog and are killed, the faster the infestation will be eliminated. A flea control plan that incorporates treatment of all animals in the home and treatment of the environment will eliminate fleas most efficiently. 

How do I give afoxolaner to my dog?

• Afoxolaner is given by mouth in the form of a chewable tablet. The tablet should always be given as directed by your veterinarian.
• Afoxolaner can be given with or without food or water.
• Be sure your dog consumes the entire dose.
• If your dog vomits within two hours of dosing, give another full dose. Try giving the next dose with food.

What if I miss giving my dog the medication?

If you miss a dose, give it as soon as you remember and start a new monthly dosing schedule. For example, if you forgot to give the dose on June 1 and remember on June 18, give the dose on June 18 and start a new monthly schedule. The next dose your dog receives will be on July 18. Do not give your dog two doses at once.

Are there any potential side effects from afoxolaner?

Most dogs have very few side effects from afoxolaner, provided it is given according to label recommendations and at the prescribed interval (or for off-label use, according to the directions given by your veterinarian).

Serious adverse reactions may occur. If any of the following signs develop, stop giving afoxolaner and contact your veterinarian immediately:

• Vomiting
• Dry/flaky skin
• Diarrhea
• Lethargy
• Lack of appetite
• Neurological signs, such as incoordination, muscle tremors, or seizures

Other side effects may occur. If you notice anything unusual, contact your veterinarian immediately.

Are there any risk factors with afoxolaner?

DO NOT USE afoxolaner in:

• Pets that are allergic to it
• Dogs less than eight weeks of age, unless instructed by your veterinarian
• Dogs that weigh less than 4 pounds (1.8 kg), unless instructed by your veterinarian

USE WITH CAUTION in:

• Dogs with a history of seizures
• Dogs that are breeding, pregnant, or lactating (safety has not been evaluated)

Are there any drug interactions that I should be aware of?

There are no documented drug interactions for afoxolaner. Be sure to tell your veterinarian about any medications (including vitamins, supplements, or herbal therapies) that your pet is taking before starting any treatment.

• Is any monitoring needed with this medication?
• There is no specific monitoring required for dogs receiving afoxolaner.
• Your veterinarian will let you know when and how they want to reassess your pet to ensure the medication is working and not causing side effects.
• At home, monitor for any side effects such as those noted above. If any occur, stop using the medication and contact your veterinarian.

How do I store afoxolaner?

• Store afoxolaner-based products at room temperature, below 86°F (30°C).
• Store in a cool, dry place, away from heat.

What should I do in case of an emergency?

If you suspect an overdose or an adverse reaction to the medication, call your veterinary office immediately. If they are not available, follow their directions in contacting an emergency facility. Be prepared to provide information about the product and your pet's weight and symptoms.