The US Food and Drug Administration (FDA) considers two drug preparations to be therapeutically equivalent if certain criteria are met.


Criteria for therapeutic equivalence - all of the following:

(1) drug preparation approved as safe and effective

(2) adequate labeling

(3) manufactured in compliance with Good Manufacturing Practices (GMP)

(4) pharmaceutical equivalence (see below)

(5) bioequivalence (see below)


Pharmaceutical equivalence involves both of the following:

(1) The preparation contains identical amounts of the same active drug ingredients in the same dosage form and route of administration, AND

(2) The preparation meets a standard for strength, quality, purity and identity.


Bioequivalence involves one of the following:

(1) no known or potential problem in bioequivalence

(2) known or potential problem in bioequivalence, but preparation shown to be bioequivalent using an appropriate bioequivalence standard


A therapeutically equivalent product may differ from the reference product in:

(1) shape

(2) scoring

(3) configuration

(4) release mechanism

(5) packaging

(6) excipient

(7) expiration date

(8) minor aspects of label

(9) storage conditions


In general a therapeutically equivalent drug preparation can be substituted for the reference drug. Rarely the reference drug may be preferred for therapy of a particular patient because of some specific feature.


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