Animal & Veterinary

Generic Animal Drugs: Approved or Unapproved?

As used on this page, the term “unapproved animal drug” refers to a drug intended for use in animals that meets the definition of “new animal drug” in the Federal Food, Drug, and Cosmetic Act but does not have legal marketing status.

Generic animal drugs are not the same as unapproved animal drugs. Unlike unapproved animal drugs, generic animal drugs have gone through an FDA pre-market review and obtained legal marketing status. The pre-market review is integral to FDA’s ability to protect animal and public health. During the review, the agency evaluates information submitted by the drug company to make sure the generic drug is safe and effective for its intended use and that the generic drug is properly manufactured and properly labeled.

Approval Process for Generic Animal Drugs

What is “marketing exclusivity”?

FDA gives “marketing exclusivity” to a drug company that gets a brand name animal drug approved. Starting on the date of approval, marketing exclusivity is the time period during which FDA will not approve a generic copy of the approved brand name animal drug. The marketing exclusivity lasts for five years for a first-time approval of an animal drug and three years for subsequent approvals of that drug. For example, the first time FDA approves a dewormer in horses, the drug company receives five years of marketing exclusivity. If FDA later approves that same dewormer for cows, the company receives three years of marketing exclusivity.

What are “exclusive marketing rights”?

“Exclusive marketing rights” apply to designated brand name animal drugs for minor species or minor uses in a major species (called “MUMS drugs”). FDA gives seven years of exclusive marketing rights to a drug company that gets a brand name MUMS drug designated and then approved, or conditionally approved. This means FDA cannot approve a generic copy or another brand name version for seven years from the date of approval, or conditional approval, of the designated brand name MUMS drug.

In general, FDA will not approve a generic animal drug until after any relevant patents, marketing exclusivities, or exclusive marketing rights for an approved brand name animal drug have expired. (The approved brand name animal drug is also called the “reference-listed new animal drug product” or the “pioneer” animal drug.) Rather than the full New Animal Drug Application process that a brand name animal drug goes through, a generic animal drug goes through the Abbreviated New Animal Drug Application process. The process is "abbreviated” because the drug company doesn’t have to conduct new safety and effectiveness studies with the generic animal drug. The Generic Animal Drug and Patent Term Restoration Act (GADPTRA) established the approval process for generic animal drugs in 1988.

Quality and Performance

FDA requires a generic drug to have the same quality, performance, and intended uses as the brand name drug. Before marketing a generic animal drug, the drug company must prove to FDA that the generic copy is the same as the approved brand name animal drug in:

  • Active ingredient;
  • Strength;
  • Dosage form; and
  • Dosage regimen, including route of administration.

The drug company must also prove to FDA that the generic copy is bioequivalent to the approved brand name drug. This means that the generic drug is absorbed by and performs the same way in the animal’s body as the brand name drug.

Manufacturing and Labeling

What does “dosage form” mean?

The dosage form is the drug’s physical form when it comes out of the manufacturing facility. There are several types of dosage forms, including oral and injectable. A drug given by mouth is an oral dosage form. Tablets and capsules are two variations of an oral dosage form. A drug that is injected under the skin, into muscle, or into a vein is an injectable dosage form. A solution is a common type of an injectable dosage form.

What does “dosage regimen” mean?

The dosage regimen includes:

  • How much of the drug to give (the dose);
  • How often to give it (the frequency);
  • How long to give it (the duration); and
  • How to give it (the route of administration). Various routes of administration include injecting the drug under the skin, into muscle, or into a vein; giving the drug by mouth; or applying the drug topically to the skin.

FDA requires that the generic drug be manufactured under the same strict manufacturing standards as the brand name drug. The manufacturing processes for the generic copy must consistently produce a product that is equivalent to the brand name animal drug in identity, strength, purity, and quality.

The labeling for the generic copy must match the labeling for the approved brand name animal drug. The labeling may differ only in items that are specific to the generic drug, such as trade name, logo, and company name and address. For example, Heartgard® Tablets is the trade name of a brand name heartworm preventive. Iverhart™ Tablets is the trade name of a generic copy.

Generic Name versus Generic Drug

A “generic name” is not the same as a “generic drug.” The term “generic name” refers to the drug’s established name, also called the active ingredient. In the heartworm preventive example above, the active ingredient in both Heartgard® Tablets and Iverhart™ Tablets is ivermectin. Ivermectin is the generic (established) name of both products, and Iverhart™ Tablets is the trade name of the generic drug.

Trade NameGeneric NameEstablished NameActive Ingredient
Heartgard® Tabletsaivermectinivermectinivermectin
Iverhart™ Tabletsbivermectinivermectinivermectin

aHeartworm preventative for dogs marketed by Merial, Inc. under New Animal Drug Application 138-412.
bHeartworm preventative for dogs marketed by Virbac AH, Inc. under Abbreviated New Animal Drug Application 200-270. Iverhart™ Tablets are a generic copy of Heartgard® Tablets.

Take-Home Points

Because unapproved animal drugs have not gone through an FDA pre-market review, there’s no way to know if these drugs are safe, effective, and quality manufactured. In contrast, FDA evaluates generic animal drugs before they are marketed to ensure they meet the agency's strict standards for safety and effectiveness and are properly manufactured and properly labeled.

Resources for You

The following FDA Web pages discuss generic drugs for people. Like a generic drug for animals, a generic drug for people is compared to a brand name drug, which is called the “innovator drug.” For animal drugs, the comparable brand name drug is called the “pioneer drug.” Despite this difference in terminology, the concepts generally apply to generic drugs for both people and animals:


Page Last Updated: 03/22/2018
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