(CNN) -  It's not the color, but what's inside that counts when
it comes to medication. However, doctors suspect that's not
exactly how patients see it.  According to a study published
Monday in the medical journal Archives of Internal Medicine,
changes in pill color significantly increase the odds that a
patient will fail to take their medication as prescribed by
their doctor.  First, the basics  Generic drugs are approved by
the U.S. Food & Drug Administration's Office of Generic Drugs.
These off-brand alternatives must be "bioequivalent" to the
brand-name version, meaning they must be identical in terms of
dosage form, strength, route of administration, quality,
intended use, and clinical efficacy. But the FDA does not
require that the two versions look alike.  Generics are big
business worldwide. In America, they account for more than 70%
of prescriptions dispensed, but only 16% of spending. Generic
prescriptions are expected to increase even more, as top-selling
brand-name medications reach the end of th