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Sentinel by Virbac

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Sentinel® Flavor Tabs®

Sentinel's Generic Name:

Lufenuron + Milbemycin oxime

Sentinel General description:

A monthly pill which prevents flea infestation and heartworm and kills parasites such as hookworms, roundworms and whipworms. Flavored tablets are available in a 6 or 12 month supply. Lufenuron and milbemycin does not kill adult fleas, so using an adulticide (ex. nitenpyram) may be desirable.

What is Sentinel?
• Milbemycin oxime eliminates the tissue stage of heartworm larvae and the adult stage of hookworm, roundworm and whipworm infestations
• Lufenuron is an insect development inhibitor. It interrupts the life cycle of the flea to prevent the continuing reproduction of new generations
• Lufenuron and milbemycin flavored tablets are given by mouth

Reasons for prescribing heartworm prevention:
• To prevent heartworm disease and roundworm, hookworm and whipworm infections in dogs
• To prevent and control flea infestations in dogs

What dogs/cats should not take Sentinel?
• This product is not approved for use in cats
• Puppies less than 4 weeks of age
• Dogs with a body weight less than 2 pounds
• Dogs who have tested positive for heartworm
• Safe for all breeds of dogs
• Safe for breeding, pregnant or nursing animals
• Pets known to have had an allergic reaction to lufenuron or milbemycin or like products


Give the oral medication as directed by your veterinarian. Your veterinarian will choose the package size appropriate to your pet's weight. Read and follow the label carefully.

Give this medication with a meal.

Ensure your pet consumes the entire dose. If it is not entirely consumed, re-dose the full recommended dose as soon as possible.

Lufenuron and milbemycin is given once a month, preferably on the same day of each month. Administer from the onset of flea and mosquito seasons. Treatment may continue year-round or for as long as flea and mosquito seasons lasts in your climate. Discuss this with your veterinarian.

If the animal vomits within 2 hours of the dose, and you feel it is unrelated to the medication, give another dose.

Missed doses reduce the effectiveness of therapy.

In multi-pet households all pets should be treated for maximum effectiveness.

If this product replaces another type of heartworm preventive, the first dose must be given within 30 days after the last dose of the previous product.

What if dose is missed?

If a dose is missed, give it as soon as you can. If it is time already for the next dose, skip the missed dose and go back to the normal schedule. Do not give two doses at the same time. If you miss more than 8 weeks in a row, give the drug as soon as you remember, but you should have your pet's blood tested for heartworms within 6 months (as infection may have occurred).

What to tell/ask veterinarian before giving Sentinel?
• What tests may need to be performed prior to treatment with this drug
• What are the risks and benefits of using this drug?
• If your pet has experienced side-effects on other drugs/products
• If your pet has experienced any other medical problems or allergies now or ever
• All medicines and supplements that you are giving your pet or plan to give your pet, including those you can get without a prescription. Your veterinarian may want to check that all of your pet's medicines can be given together.
• If your pet is pregnant or nursing or if you plan to breed your pet

Sentinel Storage and Warnings:

Store at room temperature away from heat and direct sunlight.

Remove tablet from original pack only at time of administration.

Humans should maintain good personal hygiene as hookworm and roundworm infections could easily be contracted.

Do not allow pets to eat rodents or raw flesh or fish. Pet feces should be removed daily and the premises kept clean.

Keep this and all medication out of reach of children and pets. Call your physician immediately if you accidentally take this product.

Potential side effects of Sentinel:
• A mild, transient hypersensitivity reaction (labored breathing, vomiting, salivation and lethargy) has been noted in some dogs carrying a large number of circulating microfilariae (immature heartworm). These reactions are likely due to the parasites dying all at once.
• In order for lufenuron and milbemycin to work against fleas, fleas must first bite the pet. This can be a problem in a flea-allergic pet. For these pets, combine lufenuron and milbemycin with a product that actually kills adult fleas (ex. nitenpyram).
• Upset stomach, vomiting, diarrhea, drooling and decreased appetite
• May also cause itchiness, hives and red skin, lethargy, depression, staggering, convulsions, weakness
• More serious side effects could occur in a dog with preexisting heartworm infection
• If you notice anything unusual, contact your veterinarian


Contact your veterinarian immediately if pet consumes more than the prescribed amount.

What else should I know about Sentinel?

Notify your veterinarian if your animal's condition does not improve or worsens despite this treatment.

As with all prescribed medicines, lufenuron and milbemycin should only be given to the dog for which it was prescribed. It should be given only for the condition for which it was prescribed.

This is just a summary of information about lufenuron and milbemycin. If you have any questions or concerns about lufenuron and milbemycin or the conditions for which it was prescribed, contact your veterinarian.

Milbemycin oxime
(Interceptor, Sentinel) 

Common Drug Name
Milbemycin oxime

Common Brand Names 
Single Ingredient Products  Interceptor Flavor Tabs for Dogs
Interceptor Flavor Tabs for Cats

Combination Products 
Sentinel Flavor Tabs: Contain milbemycin oxime and lufenuron 

No generic products are available. 

Store at room temperature. 


Dogs: Milbemycin oxime is used as a heartworm preventive, controls  adult hookworms, and removes and controls adult roundworms and whipworms. The lufenuron in Sentinel is used for the prevention and control of flea infestations by stopping flea egg development.

Cats: Milbemycin oxime is used as a heartworm preventive, and in the removal of certain types of adult roundworms and  hookworms. Sentinel is not approved for use in cats.

Dose and Administration 
Always follow the dosage instructions provided by your veterinarian. If you have difficulty giving the medication, contact your veterinarian.

Follow your veterinarian?s directions on when to give this medication. If advised to give it seasonally for heartworm prevention, remember to give it during and 1 month beyond the mosquito season, preferably on the same date each month. The tablet kills the parasites acquired during the previous month. (The tablet given May 1st treats exposures to heartworm during the month of April.) 

If a dose is missed, give the tablet imme-diately and  resume giving a tablet every 
30 days (once a month). Contact your veterinarian regarding the need  to have your pet heartworm tested  in 6-7 months.

For Sentinel Flavor Tabs, the  medication MUST be given with food to increase absorption of the lufeneron. Be sure the entire dose has been consumed. If it is not entirely consumed, redose once with the full recommended dose as soon as possible. Interceptor Flavor Tabs do not need to be given with a meal.

If switching from a once-a-day heartworm preventive (diethylcarbamazine) give milbemycin within 30 days of discontinuing the diethylcarbamazine.

This medication should only be given to the pet for whom it was prescribed.

Possible Side Effects 
Side effects are rare at the recommended heartworm prevention dosage. May see depression, lethargy, vomiting, staggering, loss of appetite, diarrhea, seizures, weakness, or excessive salivation. If you observe any of these signs, contact your veterinarian.

If your pet experiences an allergic reaction to the medication or to dying  parasites, signs may include facial swelling, hives, scratching, sudden onset of diarrhea, vomiting, shock, seizures, pale gums, cold limbs, or coma. If you observe any of these signs, contact your veterinarian immediately.

Not for use in animals who are hypersensitive (allergic) to it. 

Consult your veterinarian regarding heartworm testing your pet prior to, and during, treatment with this medication.

Not for use in Collies or other herding breeds over the recommended heartworm prevention dose unless under the strict supervision of a veterinarian. (Doses larger than those for heartworm  prevention are used to treat mange.) If your dog is one of these breeds and is receiving a higher dose, observe your pet for at least 8 hours after giving the medication for weakness, staggering, fever, dilated pupils, trembling, or pressing the head against a wall. Contact your veterinarian immediately if you see these signs.

Do not use in puppies less than 4 weeks of age or less than 2 pounds, or in kittens less than 6 weeks of age or less than 1.5 pounds.
Consult your veterinarian regarding physical examinations and heartworm testing for your pet prior to, and during, treatment with milbemycin oxime.

Properly dispose of unused milbemycin, as it may be toxic to fish and other animals.

Human Precautions
Some intestinal parasites may be zoonotic (able to infect humans). Consult your veterinarian or physician on how to prevent human infection and reinfection of your pet. 

Drug, Food and Test Interactions
Notify your veterinarian of any other medications, including vitamins and supplements, your pet is taking while your pet is receiving milbemycin.

No known drug or food interactions.

Signs of Toxicity/Overdose
Rare. May see any of the above side effects. 

If you know or suspect your pet has had an overdose, or if you observe any unusual signs, symptoms, or behaviors, contact your veterinarian immediately.

Keep this and all other medications out of the reach of children and pets.
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