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By Rania Gollakner, BS, DVM, MPH


What is nitenpyram?

Nitenpyram (brand names: Capstar®, Bestguard®) is a systemic insecticide used to treat adult flea infestations. It may also be effective in treating fly larvae (maggots).

While use in cats and dogs is on label, its use in reptiles to treat maggots is ‘off label’ or ‘extra label’. Many drugs are commonly prescribed for off label use in veterinary medicine. In these instances, follow your veterinarian’s directions and cautions very carefully as their directions may be significantly different from those on the label.

How quickly does it kill fleas?

Fleas begin to die approximately 30 minutes after dosing, and the effects will last up to 24-48 hours.

How is nitenpyram given?

Nitenpyram is given by mouth in the form of a tablet. It should be given with a meal.

This medication will take effect quickly, in about 1 to 2 hours, and improvement in clinical signs should follow.

What if I miss giving my pet the medication?

Give the missed dose as soon as you remember, and then wait the recommended amount of time between doses. Never give your pet two doses at once or give extra doses.

Are there any potential side effects?

Side effects are uncommon. Rarely reported side effects include increased or decreased energy, itching, vomiting, diarrhea, or lack of appetite. Serious side effects include trouble breathing, drooling, stumbling, weakness, seizures, hives, excessive panting, and big pupils.

This short-acting medication should stop working within 24 hours, although effects can be longer in pets with liver or kidney disease.

Are there any risk factors for this medication?

Do not use nitenpyram pets that are allergic to it. Do not use in pets under 2 pounds of body weight or younger than 4 weeks old. Nitenpyram should be used cautiously in pets between 4 to 8 weeks of age or pets that are thin or debilitated. Use cautiously in pregnant or nursing pets, although use is likely safe.

Are there any drug interactions I should be aware of?

There are no specific drug interactions with nitenpyram. Be sure to tell your veterinarian about any medications (including vitamins, supplements, or herbal therapies) that your pet is taking.

Is there any monitoring that needs to be done with this medication?

There is no specific monitoring that needs to be done while your pet is taking this medication. Your veterinarian may monitor your pet to be sure that the medication is working.

How do I store nitenpyram?

Store the tablets at room temperature between 59°F and 77°F (15°C and 25°C ), protected from light.

What should I do in case of 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.

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