As a group, persons age 65 and older are the largest consumers of phar
maceuticals, accounting for 30% of prescription drugs and 40% of over-
the-counter medications. Many elderly ly patients take multiple medica
tions for a variety of concurrent medical conditions. The use of two o
r more drugs, combined with widely varying degrees of disease-related
and physiologic impairment of function, can lead to unintended adverse
reactions and even death. The physician can help to minimize adverse
drug reactions and improve outcomes by being aware of the principles o
f clinical pharmacology, the characteristics of specific drugs, and th
e special physical, psychological, and social needs of older patients.