Name two age-related pharmacokinetic changes that impact medication therapy in older adults.

• A. Increased renal function and enhanced hepatic metabolism.
• B. Decreased renal function and reduced hepatic metabolism, leading to slower clearance.
• C. Higher volume of distribution for all drugs in older adults.
• D. Faster drug clearance with age.

Answer: (B)

In older adults, two main pharmacokinetic changes affect how drugs are cleared from the body: reduced renal function and diminished hepatic metabolism. As people age, kidney function often declines, meaning drugs that are eliminated by the kidneys are cleared more slowly. At the same time, hepatic metabolism tends to decrease due to factors like reduced liver mass and blood flow, which lowers the body’s ability to metabolize drugs. Together, these changes slow overall drug clearance, leading to higher and longer-lasting drug exposure from standard doses.

This is why dosing often needs adjustment in the elderly for drugs that rely on kidney excretion or hepatic metabolism, with closer monitoring for toxicity.