NexGard and NexGard Plus for Dogs, NexGard Combo for Cats

PetMD’s medications content is written and reviewed by veterinary professionals to answer common questions about how medications work, their side effects, and what species they are prescribed for. This content should not replace advice from your veterinarian. 

What Is NexGard Used for in Dogs and Cats?

NexGard products are medications used to prevent and treat certain external and internal parasites in dogs and cats. Pets can be exposed to parasites year-round, regardless of season or climate. 

NexGard products come in multiple strengths and formulations, including options combined with other parasite preventives. Use NexGard products only as prescribed by your veterinarian. 

These medications are dosed by species and weight, so it’s important to use the correct product and strength for your pet. Using cat medications on dogs or using dog medications on cats can cause serious problems, including lack of efficiency or an overdose. 

NexGard for Dogs 

NexGard is a prescription oral chewable tablet used in dogs to treat and prevent fleas and to kill four types of ticks (American dog tick, black-legged tick, Lone Star tick, and brown dog tick). 

NexGard is approved for dogs and puppies 8 weeks of age and older weighing more than 4 pounds. 

Veterinarians may also prescribe NexGard extra-label to treat demodectic mange, sarcoptic mange, and ear mites in dogs. Extra-label use means a veterinarian is prescribing a medication in a way that isn’t listed on the label. Your veterinarian will decide whether this use is appropriate for your dog. 

NexGard Plus for Dogs

NexGard Plus is a prescription oral chew used in dogs to help prevent heartworm disease, treat and control hookworms and roundworms, and treat and prevent fleas and four types of ticks (American dog tick, black-legged tick, Lone Star tick, and brown dog tick). 

NexGard Plus is approved for dogs and puppies 8 weeks of age and older weighing more than 4 pounds. 

Because it contains afoxolaner, veterinarians may also prescribe NexGard Plus extra-label to treat demodectic mange, sarcoptic mange, and ear mites in dogs. 

NexGard Combo for Cats 

NexGard Combo is a prescription topical medication used in cats to help prevent heartworm disease and to treat and control roundworms, hookworms, tapeworms, and fleas. It also kills two types of ticks (black-legged tick and Lone Star tick). 

NexGard Combo is approved for cats and kittens 8 weeks of age and older weighing more than 1.8 pounds. 

Veterinarians may also prescribe NexGard Combo extra-label to treat ear mites, notoedric mange, and cat lice.  

NexGard Considerations for Dogs and Cats

NexGard for Dogs 

Use NexGard with caution in dogs with a history of seizures or other neurologic disorders. 

At the time of publication, safety studies had not been performed to evaluate NexGard in breeding, pregnant, or nursing dogs. 

NexGard Plus for Dogs 

Use NexGard Plus with caution in dogs with a history of seizures or other neurologic disorders.  

At the time of publication, safety studies had not been performed to evaluate NexGard Plus in breeding, pregnant, or nursing dogs. 

The manufacturer has tested NexGard Plus for safety in dogs with the MDR1 mutation, and no adverse effects were observed. Dogs with the MDR1 mutation are not considered at increased risk for adverse effects. 

NexGard Combo for Cats 

Use NexGard Combo with caution in cats with a history of seizures or other neurologic disorders. 

At the time of publication, safety studies had not been performed to evaluate NexGard Combo in breeding, pregnant, or nursing cats. 

How Does NexGard Work in Dogs and Cats?

NexGard for Dogs 

The active ingredient in NexGard is afoxolaner.  

• Afoxolaner is an isoxazoline that kills fleas and ticks by overstimulating their nervous system, leading to paralysis and death. 

NexGard Plus for Dogs 

NexGard Plus contains afoxolaner plus two additional antiparasitic medications: 

• Moxidectin is a macrocyclic lactone that helps prevent heartworm disease and treats certain intestinal parasites by disrupting nerve signaling, leading to paralysis and death. 

• Pyrantel is a dewormer that treats hookworms and roundworms by paralyzing the worms so they can be passed in the stool. 

NexGard Combo for Cats 

NexGard Combo contains three ingredients: esafoxolaner, eprinomectin, and praziquantel. 

• Esafoxolaner is an isoxazoline that kills fleas and ticks by overstimulating their nervous system, leading to paralysis and death. 

• Eprinomectin is a macrocyclic lactone that helps prevent heartworm disease and treats certain intestinal parasites by disrupting nerve signaling, leading to paralysis and death. 

• Praziquantel treats tapeworms by damaging the worm’s outer surface, causing it to die and then be digested or passed in the stool. 

How Do You Give NexGard to Dogs and Cats?

NexGard for Dogs 

Follow the directions on the drug label or as provided by your veterinarian. 

• Give by mouth once monthly year-round. 

• You can give NexGard with or without food. If your dog vomits within two hours of receiving a dose, contact your veterinarian—another full chew may be recommended. 

NexGard Plus for Dogs 

Follow the directions on the ​​​drug label​ or as provided by your veterinarian. 

• Give by mouth once monthly year-round. 

• You can give NexGard Plus with or without food. 

NexGard Combo for Cats 

Follow the directions on the drug label or as provided by your veterinarian. 

• After parting the fur, apply NexGard Combo to the exposed skin on the midline of the neck, between the base of the head and the shoulder blades, where your cat cannot lick. 

• If your cat’s weight requires a second applicator, apply the contents in the same manner, in the same location. 

• Apply once monthly year-round. 

• Avoid contact with the application site for four hours, until dry. Do not allow your cat or any other pets in the household to lick the application site. 

What Happens If You Miss a Dose of NexGard? 

Speak with your veterinarian about what to do if you forget to give a dose of NexGard or NexGard Plus to your dog. Generally, they may instruct you to give it when you remember and then to resume a monthly dosing schedule.  

Speak with your veterinarian about what to do if you forget to administer a dose of NexGard Combo to your cat. Generally, your veterinarian may instruct you to apply it when you remember and then to resume a monthly dosing schedule.  

It’s important to give these medications at monthly intervals year-round. 

Do not give extra or double doses. 

What Are the Side Effects of NexGard in Dogs and Cats?

NexGard and NexGard Plus for Dogs 

NexGard and NexGard Plus are well tolerated in most dogs. Rare side effects may include: 

• Gastrointestinal upset (vomiting, diarrhea, or loss of appetite) 

• Dry or itchy skin 

• Low energy (lethargy) 

• Allergic reactions (hives or facial swelling) 

Neurologic side effects have been seen after using medications in this class of drugs. Tell your veterinarian if your dog has a history of seizures or other neurologic disease. Neurologic side effects may include: 

• Muscle tremors 

• Loss of balance, difficulty walking 

• Seizures 

Contact your veterinarian immediately if your dog has any of these symptoms. 

NexGard Combo for Cats 

Cats may drool excessively if NexGard Combo is accidentally administered by mouth or if it’s ingested through licking/grooming the application site. 

NexGard Combo is well tolerated in most cats. Uncommon side effects may include: 

• Vomiting 

• Hair change at the application site 

• Loss of appetite 

• Low energy (lethargy) 

Neurologic side effects have been seen after using medications in this class of drugs. Tell your veterinarian if your cat has a history of seizures or other neurologic disease. Neurologic side effects may include: 

• Muscle tremors 

• Loss of balance, difficulty walking 

• Seizures 

Contact your veterinarian immediately if your cat has any of these symptoms. 

Human Side Effects 

These medications are not intended for use in humans. 

Warnings for NexGard Combo topical medication include: 

• Wash hands with soap and water after application. 

• Avoid contact with your eyes. If the medication gets into your eyes, rinse thoroughly with water. If you wear contact lenses, flush eyes with water first, remove lenses, then continue rinsing. 

Due to possible side effects, humans should never use medicine dispensed for their pets and pets should not be given any medicine dispensed for a human’s use. 

If you accidentally ingest a pet medication, seek medical attention or call Poison Control at 800-222-1222. 

Monitoring Your Pet 

Prior to administration of NexGard Plus chews, dogs should be tested for existing heartworm infection. 

No specific monitoring is required by the manufacturer for NexGard or NexGard Combo, but your veterinarian may recommend routine testing depending on your pet’s individual needs, other medications they may be on, and/or the issue that initially caused your pet to be placed on this medication. 

When Should You Call Your Veterinarian? 

Call your veterinarian if you see any of the following, or if you have additional questions or concerns about the use of NexGard products: 

• Severe side effects occur  

• Your pet’s condition worsens or does not improve  

• You suspect an overdose 

What Happens If a Pet Overdoses on NexGard?

NexGard and NexGard Plus both have a wide margin of safety. Vomiting may be the only sign of an overdose of NexGard. 

NexGard Combo has a wide margin of safety. Rarely, neurological symptoms such as loss of balance, muscle tremors, low body temperature, and dilated pupils may be seen. 

If you suspect an overdose, seek emergency veterinary care or contact an animal poison control center. Consultation fees may apply. 

• Pet Poison Helpline: 855-764-7661 

• ASPCA Animal Poison Control: 888-426-4435 

How Should ​NexGard​ Be Stored for ​Dogs and Cats?​​

Keep the following storage tips in mind for this medication: 

• Store NexGard at controlled temperatures at or below 86 F (30 C). Brief exposure to temperatures up to 104 F (40 C) is acceptable. 

• Store NexGard Plus at controlled temperatures at or below 77 F (25 C). Brief exposure to temperatures up to 104 F (40 C) is acceptable. 

• Store NexGard Combo at 59–86 F (15–30 C). Brief exposure to temperatures up to 104 F (40 C) is acceptable. 

• Keep the medication in the provided blister packs until you’re ready to use it. This helps protect it from moisture and light. 

• Keep the medication out of reach of children and pets.