Final answer:
Geriatric patients often require smaller doses of medications due to a slower metabolism and changes in kidney function with aging, which can affect the pharmacokinetics of drugs and increase susceptibility to toxicity.
Step-by-step explanation:
Geriatric patients may need smaller doses of prescribed medications primarily because A) Their metabolism is slower. Aging can lead to a reduction in metabolic rate due to factors such as an underactive thyroid, where less thyroid hormones are produced, leading to a decreased rate of metabolism. In contrast, an overactive thyroid results in increased production of thyroid hormones, thereby increasing metabolic processes.
Due to these changes in metabolism and possible homeostatic imbalance, elderly patients are also more susceptible to diseases, including those that may affect the pharmacokinetics of drugs. This includes a decline in kidney function, which is responsible for the excretion of many medications, necessitating dose adjustments to prevent drug toxicity.
Additionally, aging may affect body composition, with a relative increase in fat mass and decrease in muscle mass, which can also influence drug distribution and elimination. Therefore, careful consideration and adjustment of medication dosages are required for geriatric patients to account for these physiological changes.