Milbemycin Oxime + Lufenuron

By Krista Williams, BSc, DVM, CCRP

What is milbemycin oxime + lufenuron?

Milbemycin oxime + Lufenuron (brand name Sentinel®) is a heartworm disease preventive that also treats internal parasites (e.g., hookworms, roundworms, and whipworms) and controls fleas in dogs.

Milbemycin oxime is also used ‘off-label’ to treat other mite infestations in dogs. Many drugs are commonly prescribed for off-label use in veterinary medicine. In these instances, follow your veterinarian’s directions and cautions very carefully.

How is milbemycin oxime + lufenuron given?

Milbemycin oxime + lufenuron is given by mouth as a flavored chew tablet. It must be administered with a meal or directly after your dog eats a meal to be absorbed effectively.

This medication should take effect within two days for internal parasites and within 24 hours for external parasites. Improvements in clinical signs should follow.

What if I miss giving my pet a dose?

Give the missed dose as soon as you remember and then wait the amount of time between doses, as recommended by your veterinarian, before giving the next dose. Do not give your dog two doses at once or give extra doses.

If you are using milbemycin oxime + lufenuron as a heartworm preventive and more than eight weeks have passed since giving the last dose, contact your veterinarian for guidance.

Are there any potential side effects?

At prescribed doses, milbemycin oxime + lufenuron is well-tolerated. Rarely, mild vomiting or diarrhea can occur. If you observe depression, lack of energy, weakness, itching or hives, stumbling, collapse, seizures or coma, dilated (big) pupils, or excessive drooling, contact your veterinarian immediately.

Are there any risk factors for this medication?

Milbemycin oxime + lufenuron is safe for use in most dogs. This product should not be used in dogs that are heartworm positive or have not been recently tested for heartworm, puppies less than four weeks of age, puppies or dogs weighing less than 2 lb (900 g), or dogs that are allergic to any component of the drug combination.

Some dog breeds (e.g., collies, sheepdogs, and collie or sheepdog-cross breeds) are more sensitive to milbemycin than others. This is typically due to a specific genetic mutation (MDR1) that makes them less able to tolerate high doses of milbemycin oxime. Doses used for heartworm prevention in milbemycin oxime + lufenuron are safe to use in these breeds of dogs (see the handout “Multidrug Resistance Mutation MDR1” for more information).

Your veterinarian will advise you on the safety of milbemycin oxime + lufenuron use in your dog.

Are there any drug interactions I should be aware of?

Other drugs can interact with milbemycin oxime, including cyclosporine (Atopica®), amiodarone, diltiazem, azole antifungals, and erythromycin. No interactions with lufenuron have been documented. 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?

Your pet should be tested for heartworm before receiving any product containing milbemycin oxime. If your pet has a high load of immature worms and is given milbemycin oxime, a life-threatening reaction can occur.

For breeds dog breeds with a potential milbemycin sensitivity, screening may be done ahead of receiving the drug. DNA testing can determine if your dog has the genetic mutation responsible for adverse reactions to milbemycin.

How do I store milbemycin oxime + lufenuron?

Store milbemycin oxime + lufenuron at room temperature (59-77°F, 15-25°C), in a dry place away from heat and direct sunlight. Do not store this medicine in the bathroom, near a sink, or in any other damp places. Exposure to heat or moisture may reduce the drug’s effectiveness.

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.

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