Historically, the most common intervention performed by physicians has
been the writing of a prescription. Often the prescription was a comb
ination of active agents and an inactive base. This art is no longer p
racticed in the United States. Currently, most prescriptions are writt
en for specific ''drugs.'' As the prescription is being written, the p
hysician must decide to administer a brand-name or a generic equivalen
t. Generics are a class of medications prescribed for reasons of econo
my, and the physician and the patient expect that the therapeutic effe
ct will be exactly the same as for the brand-name. Bioequivalence of s
pecific agents can be assessed using the FDA's Orange Book. In additio
n to bioequivalence, many other scientific, ethical, and economic issu
es should be considered before a decision is made. Prescribing vigilan
ce is necessary, because in many instances available information is of
ten controlling or insufficient to support rational decisions. Brand-n
ames, rather than generics, should be selected when the therapeutic in
dex is narrow or if the likelihood of generic switching is high. The p
aper will discuss all aspects of the subject.