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Therapeutic Equivalence Evaluations Codes


Therapeutic equivalence evaluations code is designed to allow users to determine quickly whether the Agency has evaluated a particular approved prescription drug product as therapeutically equivalent to other pharmaceutically equivalent prescription drug products (first letter) and to provide additional information on the basis of FDA's evaluations (second letter).


Generally, prescription drug products that the Agency considers multisource have been assigned a therapeutic equivalence code (TE codes). 


The two basic categories into which multisource drugs have been placed are indicated by the first letter of the relevant therapeutic equivalence code as follows:  

  1. Category – A: Drug products that FDA considers to be therapeutically equivalent to other pharmaceutically equivalent products.
  2. Category – B: Drug products that FDA at this time, considers not to be therapeutically equivalent to other pharmaceutically equivalent products.


Category – A drug products are which:

(1) There are no known or suspected bioequivalence problems. These are designated AA, AN, AO, AP, or AT, depending on the dosage form; or

(2) Actual or potential bioequivalence problems have been resolved with adequate in vivo and/or in vitro evidence supporting bioequivalence. These are designated AB.


The specific sub-codes of "A" codes are as below:

  • AA - Products in conventional dosage forms not presenting bioequivalence problems.
  • AB, AB1, AB2, AB3 - Products meeting necessary bioequivalence requirements.
  • AN - Solutions and powders for aerosolization.
  • AO - Injectable oil solutions.
  • AP - Injectable aqueous solutions and, in certain instances, intravenous non-aqueous solutions.
  • AT - Topical products.


Category – B drug products for which:

Actual or potential bioequivalence problems have not been resolved by adequate evidence of bioequivalence. Often the problem is with specific dosage forms rather than with the active ingredients. These are designated BC, BD, BE, BN, BP, BR, BS, BT, BX, or B*.


Drug products designated with a "B" code fall under one of three main policies:

(1) The drug products contain active ingredients or are manufactured in dosage forms that have been identified by the Agency as having documented bioequivalence problems or a significant potential for such problems and for which no adequate studies demonstrating bioequivalence have been submitted to FDA; or

(2) The quality standards are inadequate or FDA has an insufficient basis to determine therapeutic equivalence; or

(3) The drug products are under regulatory review.


The specific sub-codes of "B" codes are as below:

  • B* - Drug products requiring further FDA investigation and review to determine therapeutic equivalence.
  • BC - Extended-release dosage forms (capsules, injectables and tablets)
  • BD - Active ingredients and dosage forms with documented bioequivalence problems.
  • BE - Delayed-release oral dosage forms.
  • BN - Products in aerosol-nebulizer drug delivery systems.
  • BP - Active ingredients and dosage forms with potential bioequivalence problems.
  • BR - Suppositories or enemas that deliver drugs for systemic absorption.
  • BS - Products having drug standard deficiencies.
  • BT - Topical products with bioequivalence issues
  • BX - Drug products for which the data are insufficient to determine therapeutic equivalence.


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Note: The scientific and regulatory foundation for the evaluation of therapeutic equivalence of prescription drug products involves: pharmaceutical equivalence, bioequivalence, and same clinical effect and safety profile.


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