Interceptor Flavor Tabs for Cats is a prescription, once-a-month tablet containing milbemycin oxime. In the U.S., its cat label covers two things: prevention of heartworm disease caused by Dirofilaria immitis, and removal of adult roundworm (Toxocara cati) and hookworm (Ancylostoma tubaeforme) infections. It is labeled for cats at least six weeks old and at least 1.5 pounds. It is not labeled for fleas, ticks, or tapeworms, and it should be given only by or on the order of a licensed veterinarian.
What Interceptor is labeled to do
The FDA-hosted approved label (NADA 140-915) lists two cat indications. The first is heartworm prevention. The second is removal of existing adult roundworm and hookworm infections. Elanco’s current U.S. product page describes the product the same way: a monthly prescription product with the same age and weight threshold and the same parasite claims.
Those claims are narrower than many readers expect. The label does not say the tablet treats fleas, ticks, tapeworms, or every intestinal parasite. If your cat has a parasite outside those two claims, your veterinarian will need to choose a different approach or an additional product.
Age and weight eligibility
The label sets the minimum at six weeks of age and 1.5 pounds of body weight. Kittens and cats below either threshold are outside the labeled use. Veterinarians sometimes make exceptions in practice, but those decisions fall outside the label and should be made only by your vet.
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#1 Best Overall
- Interceptor (milbemycin oxime) is a once-a-month tablet that prevents heartworm disease in dogs and cats.
- Protect your pet from heartworm and intestinal worms.
- One monthly tablet keeps both dogs and cats safe from heartworm disease.
- Powerful protection against heartworms and intestinal parasites.
- Just one easy-to-give dose, administered monthly, provides protection against three dangerous (and potentially fatal) infections.
Labeled dosage by weight
The label states that the product is given orally once a month at a recommended minimum dosage of 2.0 mg milbemycin oxime per kilogram (0.91 mg/lb.) of body weight. Tablet strength follows the label’s weight bands:
| Cat body weight (label band) | Tablet strength, one tablet monthly |
|---|---|
| 1.5 to 6 lb. | 5.75 mg |
| 6.1 to 12 lb. | 11.5 mg |
| 12.1 to 25 lb. | 23.0 mg |
| Over 25 lb. | Use an appropriate combination of tablets, as directed by the label and your veterinarian |
This table reproduces the labeled schedule. It is not individualized advice. Elanco states that the veterinarian prescribes the dose based on the cat’s weight, so the tablet strength your cat receives should be the one your veterinarian selects, and any weight change may call for a different strength.
Rank #2
- Interceptor (milbemycin oxime) is a once-a-month tablet that prevents heartworm disease in dogs and cats.
- Protect your pet from heartworm and intestinal worms.
- One monthly tablet keeps both dogs and cats safe from heartworm disease.
- Powerful protection against heartworms and intestinal parasites.
- Just one easy-to-give dose, administered monthly, provides protection against three dangerous (and potentially fatal) infections.
How to give the tablet
The label permits several ways of giving the tablet:
- As a treat. The tablet can be offered directly.
- In food. The tablet can be placed in a small amount of food. Commercial “cat pill pockets” are one optional food-based aid for this purpose. The label does not require or endorse any specific product, so use one only if it works for your cat and follow your veterinarian’s directions.
- Like other tablets. The tablet can be given by pilling directly.
- Broken. The label allows the tablet to be broken to make administration easier.
Whatever method you use, watch your cat to confirm the entire dose is swallowed. If the tablet is not completely consumed, the label directs one redose with the full recommended dose as soon as possible.
Rank #3
- Interceptor (milbemycin oxime) is a once-a-month tablet that prevents heartworm disease in dogs and cats.
- Protect your pet from heartworm and intestinal worms.
- One monthly tablet keeps both dogs and cats safe from heartworm disease.
- Powerful protection against heartworms and intestinal parasites.
- Just one easy-to-give dose, administered monthly, provides protection against three dangerous (and potentially fatal) infections.
Give the dose monthly, preferably on the same date each month. Choosing a consistent day, such as the first of the month, makes it easier to track.
Missed doses
The label says that if more than 30 days have passed since the last dose, the missed dose should be given immediately, and the monthly schedule then resumes. If you are unsure whether a dose was missed or whether a redose is needed, call your veterinarian before giving another tablet.
Rank #4
Heartworm testing and safety limits
Both the FDA-hosted label and Elanco recommend testing cats for existing heartworm infection before starting Interceptor. Starting a preventive in a cat that already has heartworm disease is a safety concern that the testing is meant to catch.
The safety statements in the label and Elanco’s materials are limits, not automatic bans. Each states that safety in heartworm-positive cats has not been established. The label also says that safety has not been established in breeding, pregnant, or lactating queens, or in breeding toms. These statements mean the manufacturer has not shown the product to be safe in those groups; they do not mean every such cat will be harmed. Decisions about these cats belong with your veterinarian.
Best Value
- Interceptor PLUS protects against more types of worms* than other formulas
- Tasty, monthly chicken-flavored chew with real chicken, making dosing easy
- Prevents heartworm disease plus treats and controls adult hookworm, roundworm, whipworm and tapeworm infections
- Covers worms* commonly found in dog parks trails, backyards or carried by mosquitoes
- Delivers protection for a full month * Heartworm, hookworm, roundworm, whipworm and tapeworm
Side effects: what the evidence does and does not establish
The label and manufacturer materials reviewed for this article do not provide a current feline adverse-reaction frequency table, so this article cannot list how often specific side effects occur in cats. Nothing here should be read as a claim that side effects are rare or common.
What the sources do establish is the set of safety limits above. For an individual cat, the most useful step is to ask your veterinarian to review the current full label with you, including the safety information that applies to your cat’s age, weight, health history, and reproductive status. If your cat seems unwell after a dose, contact your veterinarian promptly rather than waiting for the next scheduled dose.
Where CAPC guidance fits
The Companion Animal Parasite Council (CAPC) lists milbemycin oxime among available feline heartworm preventives and includes Interceptor in its product reference. Its ascarid and hookworm resources also name milbemycin oxime and Interceptor among relevant products or treatments. These are useful context for how veterinarians think about parasite control. They are not the product’s approved label claims, so for indications and dosing, use the FDA-hosted label.
Questions to ask your veterinarian
- Does my cat’s weight place it in the 5.75 mg, 11.5 mg, or 23.0 mg band, or does it need a combination of tablets?
- Has my cat been tested for existing heartworm infection, and what does that mean for starting Interceptor?
- Are there parasites outside the labeled claims that my cat needs covered, such as fleas, ticks, or tapeworms?
- What should I do if my cat does not finish a tablet, or if a dose is late?
- Does my cat’s age, health, or breeding status change the safety picture?
Interceptor is a prescription medication, so your veterinarian’s directions take priority over any general guidance on this page, and the current label is the authoritative source for dosing and approved claims. Confirm with your veterinarian or the current label that no newer revision applies, since the label copy used for this article does not show a revision date.
Do these 3 things before closing this tab:
1Repair Windows errors before they cause bigger problems2Fix the driver behind crashes, sound loss and screen glitches3Clear out junk files and repair common Windows errorsSources: U.S. Food and Drug Administration, approved Interceptor Flavor Tabs for Cats label (NADA 140-915); Elanco, current U.S. product information for Interceptor Flavor Tabs; Companion Animal Parasite Council (CAPC) heartworm and ascarid/hookworm guidance.
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