Final answer:
An older adult patient may be at risk for drug toxicity primarily due to reduced hepatic blood flow. The aging process can slow down the liver's ability to metabolize drugs, and a decline in renal function with a lower glomerular filtration rate can impair the kidneys' ability to excrete drugs, potentially leading to toxic levels.
Step-by-step explanation:
An older adult patient may be at risk for drug toxicity due to reduced hepatic blood flow. Aging is associated with several physiological changes that can affect drug metabolism and excretion. Reduced hepatic blood flow can slow down the liver's ability to metabolize drugs, leading to increased levels of medication in the bloodstream. This is particularly important because the liver functions to detoxify and clear medications from the body. When this process is impaired, it can cause medications to accumulate to toxic levels.
Additionally, older adults may experience a decline in renal function. As renal function decreases, characterized by a lower glomerular filtration rate (GFR), the kidneys are less capable of excreting waste products and drugs, which can also lead to toxicity. The ability to regulate water-soluble drugs is important because these drugs can be excreted in the urine; however, this ability diminishes with age due to changes in glomerular filtration, tubular secretion, or tubular reabsorption.