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Antiparasitic combination (macrocyclic lactone + insect development inhibitor) · For Dogs

Sentinel dosage reference for dogs (Milbemycin oxime / Lufenuron)

This page's standard weight-based reference is 0.5 mg per kg (0.23 mg per lb), with Once monthly recorded as the reference frequency. Use the calculator to see the arithmetic for your dog's weight, then confirm the indication, product, and actual dose with a veterinarian.

Onset
Continuous prevention (give monthly)
Duration
30 days
Class
Antiparasitic combination (macrocyclic lactone + insect development inhibitor)

Weight-based calculator estimate from the references listed on this page. This page has not been independently DVM-reviewed — see our methodology .

This information is for educational purposes only. Always consult your veterinarian before giving medication to your pet. Do not use this calculator for emergencies, overdoses, pregnancy, very young animals, very old animals, pets with liver/kidney disease, or pets taking multiple medications.

Each medication page lists the references recorded for its data. The calculator math and editorial presentation are maintained by PetDosageChart; a page is independently DVM-reviewed only when a named reviewer byline appears. See our methodology and limitations.

Milbemycin oxime / Lufenuron (often known by brand names such as Sentinel and Sentinel Flavor Tabs) is an antiparasitic combination (macrocyclic lactone + insect development inhibitor) commonly used in veterinary medicine for Heartworm prevention, Flea development prevention, and Intestinal parasite control (roundworms, hookworms, whipworms). Understanding the correct dosage, administration, and potential side effects of Milbemycin oxime / Lufenuron is critical for your dog’s safety and well-being.

A typical Milbemycin oxime / Lufenuron dose for dogs is around 0.5 mg/kg Once monthly, within a usual range of 0.5-1 mg/kg. Available forms include Flavored tablet.

Calculator Warning: Use this only as an educational estimate. Your veterinarian may prescribe a different dose based on your pet’s condition, age, weight, other medications, and medical history.

Milbemycin oxime / Lufenuron Dosage Calculator for Dogs

Enter your dog’s weight below to estimate the Milbemycin oxime / Lufenuron dose from the 0.5 mg/kg guideline. Your veterinarian may adjust it for your dog’s age, condition, and other medications, so treat the result as an educational starting point, not a prescription.

Dosage Calculator · 01

Enter your dog's weight

Quick Dosage Chart

Typical Milbemycin oxime / Lufenuron amounts for common dog weights, for quick reference:

Dosage Chart · 02

Sentinel weight-based reference chart for dogs

Scroll sideways to see full table

Weight Lower Reference Standard Reference Upper Reference Frequency
5 lbs (2.3 kg) 1.1 mg 1.1 mg 2.3 mg Once monthly
10 lbs (4.5 kg) 2.3 mg 2.3 mg 4.5 mg Once monthly
15 lbs (6.8 kg) 3.4 mg 3.4 mg 6.8 mg Once monthly
20 lbs (9.1 kg) 4.5 mg 4.5 mg 9.1 mg Once monthly
25 lbs (11.3 kg) 5.7 mg 5.7 mg 11.3 mg Once monthly
30 lbs (13.6 kg) 6.8 mg 6.8 mg 13.6 mg Once monthly
40 lbs (18.1 kg) 9.1 mg 9.1 mg 18.1 mg Once monthly
50 lbs (22.7 kg) 11.3 mg 11.3 mg 22.7 mg Once monthly
60 lbs (27.2 kg) 13.6 mg 13.6 mg 27.2 mg Once monthly
70 lbs (31.7 kg) 15.8 mg 15.8 mg 31.7 mg Once monthly
80 lbs (36.3 kg) 18.1 mg 18.1 mg 36.3 mg (46mg tablet) Once monthly
90 lbs (40.8 kg) 20.4 mg 20.4 mg 40.8 mg (46mg tablet) Once monthly
100 lbs (45.4 kg) 22.7 mg 22.7 mg 45.4 mg (46mg tablet) Once monthly
120 lbs (54.4 kg) 27.2 mg 27.2 mg 54.4 mg (46mg tablet) Once monthly
150 lbs (68 kg) 34.0 mg 34.0 mg 68.0 mg Once monthly

Parenthetical tablet amounts are arithmetic comparisons only. They do not account for scoring, release type, concentration, product labeling, or whether this medication is appropriate for an individual animal.

By Weight

Sentinel reference by dog weight

Choose a common weight to open its optional reference page. Use the main medication calculator for a different exact weight.

Common-weight pages are convenience views of the same educational reference, not separate medical recommendations.

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How to Give Milbemycin oxime / Lufenuron to Your Dog

Give the Sentinel flavored tablet by mouth once monthly with a full meal to ensure maximum absorption. The tablet size is based on your dog’s weight — use the size recommended by your vet. Most dogs eat the flavored tablet willingly. If your dog won’t take it voluntarily, hide it in a small amount of food or a pill pocket. Mark your calendar for consistent monthly dosing. A heartworm test is required before starting treatment.

It is generally recommended to give Milbemycin oxime / Lufenuron with food to help reduce stomach upset. It may interact with Generally safe with most medications, Use caution with other macrocyclic lactones, and P-glycoprotein inhibitors may increase toxicity risk.

Side Effects and Safety

Common side effects include Vomiting, Diarrhea, Decreased appetite, and Lethargy. More serious side effects can occur, such as Allergic reaction, Seizures (rare), Hypersalivation, and Shock-like reaction if dog has existing heartworm infection.

Cautions · 12

When Sentinel should be used with caution or avoided

Some dogs should not take Sentinel, or need a different dose and closer monitoring. Tell your veterinarian about your pet's full health history and every other medication or supplement they take before giving Sentinel.

  • Dogs with existing heartworm infection (must test negative first)
  • Known hypersensitivity to milbemycin or lufenuron
  • Puppies under 4 weeks of age or under 2 pounds

Interactions · 13

Sentinel drug interactions

Sentinel can interact with other drugs. This list is not complete — always give your veterinarian a full list of your dog's medications and supplements.

Generally safe with most medications
Use caution with other macrocyclic lactones
P-glycoprotein inhibitors may increase toxicity risk

Calculator Limits · 14

When not to use this calculator

This calculator gives a general educational estimate for a healthy adult dog at a known weight. Do not rely on it in these situations — talk to your veterinarian instead:

  • In an emergency, or after accidental ingestion or a suspected overdose
  • For pregnant or nursing pets
  • For very young or very old dogs
  • For pets with liver disease, kidney disease, or another chronic illness
  • For pets taking several medications at once
  • When you are not sure of your dog's current, accurate weight
  • For combination products that contain additional active ingredients

Overdose · 15

Suspected overdose: what to do

If you think your dog had too much Sentinel, or swallowed any medication by accident, act right away. Do not wait for symptoms to appear.

  • Call your veterinarian or the nearest emergency animal hospital.
  • ASPCA Animal Poison Control Center: (888) 426-4435
  • Pet Poison Helpline: (855) 764-7661

A consultation fee may apply to the poison hotlines. Have the medication packaging ready, and note how much your pet may have taken and when. Do not try to make your pet vomit unless a veterinarian tells you to.

When to Call the Vet

If your dog experiences any of the following, contact your veterinarian or an emergency clinic immediately:

Frequently Asked Questions

Frequently Asked · 07

Questions about this medication

Does Sentinel kill adult fleas?
No, Sentinel does not kill adult fleas. The lufenuron component prevents flea eggs and larvae from developing, breaking the flea life cycle over time. If your dog has an active flea infestation, you will need an additional product that kills adult fleas (such as Capstar or a topical flea treatment) alongside Sentinel.
Why does my dog need a heartworm test before starting Sentinel?
Giving heartworm prevention to a dog already infected with adult heartworms can cause a severe, potentially fatal reaction as the microfilariae (baby heartworms) die off rapidly. A negative heartworm test must be confirmed before starting or restarting any heartworm preventive.
Should Sentinel be given year-round?
Yes, most veterinarians recommend year-round heartworm prevention regardless of climate. Mosquitoes can appear during unexpected warm spells, and the intestinal parasite protection is beneficial year-round. Missing even one month can leave your dog vulnerable.
Can Sentinel be used alongside tick prevention?
Yes, Sentinel does not protect against ticks, so a separate tick preventive (such as a tick collar or isoxazoline product) is often recommended. Discuss combination options with your vet to ensure full parasite coverage.
What if my dog vomits after taking Sentinel?
If your dog vomits within 1-2 hours of taking Sentinel, the full dose may not have been absorbed. Contact your vet — they may recommend giving another dose. Giving Sentinel with a full meal improves absorption and reduces the chance of stomach upset.

Use This Guide Safely · 08

What weight alone cannot tell you

The calculator performs one narrow job: it multiplies your dog's weight by the lower, standard, and upper mg/kg values recorded for Sentinel. It cannot decide whether this drug, indication, formulation, or schedule is appropriate for an individual animal.

Context in this medication record

Commonly listed uses
Heartworm prevention, Flea development prevention, Intestinal parasite control (roundworms, hookworms, whipworms)
Recorded forms
Flavored tablet
Reference timing
Once monthly; onset Continuous prevention (give monthly); duration 30 days

Individual checks a calculator cannot perform

  • Confirm the diagnosis and the reason this medication is being considered.
  • Match the exact product, concentration, route, and whether a tablet may be split.
  • Account for age, pregnancy, organ function, genetics, allergies, and prior reactions.
  • Review every prescription, over-the-counter product, and supplement your pet takes.

Recorded cautions

Dogs with existing heartworm infection (must test negative first); Known hypersensitivity to milbemycin or lufenuron; Puppies under 4 weeks of age or under 2 pounds.

Recorded interactions

Generally safe with most medications; Use caution with other macrocyclic lactones; P-glycoprotein inhibitors may increase toxicity risk.

These lists reproduce the structured record used by this page and may not be exhaustive. Show your veterinarian the product label and your dog's complete medication list before acting on a number.

Related · 08

Related medications for dogs

Sources · 09

Sources & references

The structured medication record behind this page names the references below. The links open the publisher or official resource; they do not turn this page into a prescription for an individual animal.

Source names are shown at the record level; passage-level page and label citations are still being added. Read our methodology and limitations.

Transparency · 11

How this page was made

This page's structured medication record includes Plumb's Veterinary Drug Handbook among its source names. PetDosageChart applies the record's mg/kg values to the entered weight and presents the arithmetic result. A source record is not the same as an individualized prescription or an independent clinical review.

Sources cited
  • Plumb's Veterinary Drug Handbook
  • Merck Veterinary Manual
Calculator formula
Doses scale linearly from a standard basis of 0.5 mg per kg (0.23 mg per lb) of body weight, given Once monthly. The calculator multiplies that basis by your dog's weight and shows an arithmetic comparison with recorded tablet sizes. That comparison does not determine whether a tablet is scored, splittable, or appropriate for your pet.
Editorial owner
Prepared and maintained by the PetDosageChart editorial team, a software-led publisher and not a veterinary practice.
DVM review status
Not independently DVM-reviewed. A named reviewer and review date appear here only after a confirmed review.

More on our methodology and editorial process — how we source, calculate, and review dogs dosage data.

Safety · 10

More resources