In older adults, which physiological change most directly affects drug elimination?

In older adults, which physiological change most directly affects drug elimination?

• A. Diminished glomerular filtration
• B. Decreased enzyme functioning
• C. Decreased peristalsis
• D. Lower pH of gastric secretions

Answer: (A)

Drug elimination is how the body removes a drug, and in older adults the kidneys are the main route for clearing many medications. As people age, glomerular filtration rate declines because of nephron loss and vascular changes. When GFR drops, the kidneys clear fewer drug molecules each hour, so drug levels in the blood rise and the half-life lengthens. That direct reduction in clearance is why diminished glomerular filtration most directly affects elimination. Other changes, like enzyme function, mainly influence metabolism; decreased peristalsis affects absorption rather than removal; and lower gastric pH alters absorption too, not elimination.

Drug elimination is how the body removes a drug, and in older adults the kidneys are the main route for clearing many medications. As people age, glomerular filtration rate declines because of nephron loss and vascular changes. When GFR drops, the kidneys clear fewer drug molecules each hour, so drug levels in the blood rise and the half-life lengthens. That direct reduction in clearance is why diminished glomerular filtration most directly affects elimination. Other changes, like enzyme function, mainly influence metabolism; decreased peristalsis affects absorption rather than removal; and lower gastric pH alters absorption too, not elimination.