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Pharmacokinetic changes that occur with aging

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Geriatrics: Overview

There are many age-related changes that can have a significant effect on drug therapy. It is important to be aware of the complexities involved in treating this patient population in order to reduce the likelihood of an adverse event.

-Clinical Concerns-

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 age related changes.


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Pharmacokinetic changes that occur with aging