[Generic drugs: we must cut pharmaceutical spending but undertaking drug quality].
ABSTRACT The World Health Organization and all drug regulatory agencies (DRA) support the commercialization of generic medicines because they control costs and are irreplaceable therapeutic options in countries lacking the innovator product. Generic drugs are widely considered to be cost-efficient substitutes for brand-name medications. They make up about 20% of the total number of prescriptions in Spain, a figure that is still far from the use of generic drugs in USA and other European countries. Despite economical interest in this issue, in this article we review the interest of generic drugs from a pharmacological and clinical perspective that must undertake drug quality to ensure drug efficacy and safety of the patients. A generic drug (generic drugs, short: generics) is defined as "a drug product that is comparable to brand/reference listed drug product in dosage form, strength, route of administration, quality and performance characteristics, and intended use". Both the reference drug and the generic drug have to demonstrate previously they are therapeutically equivalent. With the exception of parenteral drugs, two products have demonstrated to be therapeutically equivalent if after administration in the same molar dose, their effects with respect to both efficacy and safety are essentially the same, as determined from bioequivalence studies in terms of comparison of appropriate pharmacokinetic parameters and bioavailability. Parenteral formulations, however, are not required to demonstrate therapeutic equivalence because it may be considered self-evident. Such assumptions have never been challenged, but there are reasons to do so for parenteral antimicrobials. It is interesting to highlight that although brand-name drugs and generic drugs are both approved by DRA and may be interchangeable with respect to their clinical effects, they can differ substantially in their appearance. Consumers of brand-name medications receive identical-appearing batches of pills with each refill, whereas consumers of generic drugs must be prepared to receive pills of a different size, color, and shape, depending on which manufacturer is supplying their pharmacies.