Blood levels of medications may rise in the elderly, sometimes to toxic levels. This is MOST likely due to:

• A. renal insufficiency
• B. intentional overdose
• C. splenic dysfunction
• D. pancreatic failure

Answer: (A)

In older adults, reduced kidney function commonly leads to higher blood levels of medications because the kidneys are a major route of drug elimination. As glomerular filtration rate declines with age, drugs that are cleared renally stay in the bloodstream longer, increasing their concentration and the risk of toxicity. This accumulation can occur even when doses are unchanged, since half-life is extended and clearance is reduced. Also, serum creatinine alone may not reveal the true extent of impairment because muscle mass often decreases with aging, masking reduced kidney function; estimating creatinine clearance or eGFR provides a clearer picture for dosing adjustments.

The other options don’t typically explain why drug levels rise with aging. Overdose is not a universal age-related mechanism; splenic dysfunction and pancreatic failure affect different organ systems and do not directly alter how drugs are cleared from the body.