Animal & Veterinary

How can I tell if a drug is FDA-approved for animals?

It’s not always easy to tell if a drug you prescribe for a patient is FDA-approved for animals. You can’t tell by looking at the tablet in your hand or the solution in the bottle. You can’t tell by feeling or smelling the drug. But, here are some tips to help you identify an FDA-approved animal drug:

Look at the drug’s label.

All FDA-approved animal drugs have a New Animal Drug Application (NADA) number, or for generic animal drugs, an Abbreviated New Animal Drug Application (ANADA) number. The six-digit NADA or ANADA number and the statement, “Approved by FDA,” are usually on the drug’s label.


The same approved animal drug can be legally marketed under several labels. These different labels are made by the various companies that distribute the drug. Each distributor can use a different trade name for the drug.

For example, the drug company Cross Vetpharm Group Ltd has an approved New Animal Drug Application (NADA) for phenylbutazone tablets for horses. Under this same approved application (NADA number 044-756), three distributors market the tablet, each with a different trade name:

DistributorTrade Name
Bimeda Inc.BUTATRON TABLETS
MWI Veterinary SupplyVET ONE PHENYLBUTAZONE TABLETS
Rx Veterinary ProductsPHENYLBUTAZONE TABLETS USP

This can get confusing, so it’s important to look at the drug’s label. The labels for most approved brand name animal drugs list the NADA number, and the labels for most generic animal drugs list the Abbreviated New Animal Drug Application (ANADA) number. If you order one of the above phenylbutazone tablets and see “NADA 044-756” on the label, you can be confident the drug is FDA-approved for horses.


Animal drugs conditionally approved by FDA have a Conditional New Animal Drug Application (CNADA) number. The six-digit CNADA number appears on the drug’s label as part of the following required statement:

“Conditionally approved by FDA pending a full demonstration of effectiveness under application number XXX-XXX.”

Indexed animal drugs have a Minor species Index File (MIF) number. The six-digit MIF number appears on the drug’s label as part of the following required statements:

“NOT APPROVED BY FDA. Legally marketed as an FDA Indexed Product under MIF XXX-XXX. Note -- In order to be legally marketed, an animal drug product intended for a minor species must be Approved, Conditionally Approved, or Indexed by the FDA. THIS PRODUCT IS INDEXED.”

Note that indexed animal drugs are technically not FDA-approved but still legally marketed for some minor species. Instead of using the standard approval process, indexed drugs take an alternative pathway to the marketplace.

Look up the drug in Animal Drugs @ FDA.

Most prescription and over-the counter FDA-approved animal drugs are listed in Animal Drugs @ FDA, a searchable online database. The database allows you to search using several parameters, including proprietary name (trade name), active ingredient, and application (NADA or ANADA) number.

Look up the drug in the Green Book.

Most prescription and over-the-counter FDA-approved animal drugs are included in an online list called the “Green Book.” The list is published in its entirety each January and updated monthly. While the information in the Green Book is mainly used by companies wanting to manufacture and distribute generic animal drugs, it is also a resource for the public.

The Green Book is divided into eight sections. To find out if a drug is FDA-approved for animals, the first two sections are most helpful:

    • Section 1 is divided into two subsections. Section 1.1 lists approved animal drugs sorted alphabetically by trade name. Section 1.2 lists approved animal drugs sorted by application number, from lowest to highest.
    • Section 2 lists approved animal drugs sorted alphabetically by active ingredient.

In the Green Book, the header "Application Number" refers to either a New Animal Drug Application (NADA) number for a brand name animal drug, or an Abbreviated New Animal Drug Application (ANADA) number for a generic animal drug. If the number in this column is less than 200-000, the animal drug is a brand name drug with an approved NADA. A number over 200-000 indicates the animal drug is a generic drug with an approved ANADA.

Common Misconceptions

Misconception: An animal drug is FDA-approved if the label includes an NDC number.

Truth: The presence of a National Drug Code (NDC) number on an animal drug’s label does not mean the drug is FDA-approved. Under federal law, all drug manufacturers must register with FDA and give the agency a list of their marketed drugs. This legal requirement for drug manufacturers to “register and drug list” with FDA applies to all marketed drugs, both approved and unapproved.

FDA assigns a unique ten-digit NDC number to each registered drug regardless of its approval status. Many drug manufacturers include the NDC number on the drug’s label. FDA publishes the NDC numbers of registered human drugs in the National Drug Code Directory. There is no NDC directory for registered animal drugs.

Misconception: An animal drug is FDA-approved if the label includes the statement, “Caution: Federal law restricts this drug to use by or on the order of a licensed veterinarian.”

Truth: The presence of the caution statement on the label does not mean it’s an FDA-approved prescription animal drug. Federal law requires that the caution statement be included on the label if the animal drug can only be safely used under a licensed veterinarian’s supervision. Again, this legal requirement applies to all marketed drugs, both approved and unapproved.

There are other statements on the labels of some marketed animal drugs that you should also not take to mean the drugs are FDA-approved. These statements include:

• “Registered and listed with the FDA”
• “Made in an FDA-registered facility”
• “Made in an FDA-inspected facility”
• “Made in an FDA-approved facility”

Bottom line: If you see an NDC number, the caution statement, or any of the above statements on the label, don’t assume the drug is approved. You have to look a bit harder to tell if the drug is FDA-approved for animals or people.

Page Last Updated: 07/10/2014
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