Final answer:
In older adults, reduced kidney function due to physiologic changes like lower glomerular filtration rate, less efficient tubular secretion, and reabsorption impair drug excretion, increasing the risk of drug toxicity.
Step-by-step explanation:
Physiologic changes in the kidneys of older adults, such as reduced glomerular filtration, decreased tubular secretion, and altered tubular reabsorption, contribute to a reduction in drug excretion. Aging kidneys may demonstrate a diminished number of functioning nephrons, decreased renal blood flow, and impairments in the renin-angiotensin-aldosterone system, leading to altered handling of water-soluble drugs. These age-associated renal changes can lead to an increased risk of drug toxicity due to prolonged drug half-life and accumulation.
Older adults experience a natural decline in kidney function, marked by lower glomerular filtration rate and less efficient excretion processes like tubular secretion and reabsorption. As renal blood flow diminishes and nephrons lose functionality over time, the ability to filter waste products and drugs from the bloodstream weakens. Specific mechanisms affected include carrier-mediated secretion and passive reabsorption along concentration gradients, which can increase the half-life of drugs and heighten susceptibilities to adverse effects. Consequently, medication dosages often need adjustment to avoid potential toxicity in the elderly.