Since the mid-1970s, the Food and Drug Administration has required that generic drugs have the same therapeutic effects as brand name drugs when administered to people under the conditions spelled out in the labeling. When this is the case, the drug products are said to be bioequivalent.
Describes drug preparations which have the same bioavailability. Such drugs are chemically equivalent (indistinguishable by chemical means) although chemically equivalent preparations are not always bioequivalent. Bioequivalence is a function of bioavailability and the terms are often used synonymously. Chemically equivalent drugs which are bioequivalent are therapeutically equivalent (have the same treatment effect), although therapeutically equivalent preparations need not be either chemically or bioequivalent.