are many age-related changes that can have a significant effect
on drug therapy. It is important to be cognizant of the
complexities involved in treating this patient population in
order to reduce the likelihood of an adverse event.
Multiple diseases: The elderly in general have an
increased incidence of chronic disease. 80% of the elderly have
at least one chronic disease, and many of them have multiple
diseases. This is particularly evident after age 75. The most
common diseases include: arthritis, hypertension, hearing
impairment, heart disease, vision impairment, orthopedic
disabilities and diabetes mellitus.
Multiple medications: The elderly make up approximately 13%
of the U.S. population, however, as a group they use
approximately one-third of all prescriptions written each year
and 40% of all over-the-counter medications used annually. On
average, the elderly take approximately three times as many
medications as younger patients. Thus,
the elderly have ample potential for drug-related adverse events
based on the number of medications alone. This is intensified by
the age-related changes discussed above. It is important to use
the lowest possible dose without sacrificing efficacy. Dosage
reductions in many cases may help eliminate or reduce the risk
of an adverse event.
Adverse drug reaction rate: The elderly experience an ADR
rate that is conservatively reported to be 2-3 times that of
younger adults. Most of the higher rate can be explained by
changes in renal and hepatic function, and body composition
associated with aging. Another important factor is the number of
medications the elderly consume.
Clinically significant changes in metabolism, distribution and
excretion occur in the elderly. It is vitally important to make
appropriate changes in drug therapy to account for these