What is a primary consequence of aging regarding drug distribution in the body?

Aging significantly alters drug distribution in the body primarily due to physiological changes that occur over time. One of the main changes associated with aging is the alteration in body composition, such as an increase in body fat and a decrease in lean body mass and total body water. These shifts can affect how drugs are distributed throughout the body.

For instance, lipophilic (fat-soluble) drugs may have an increased volume of distribution in older adults, leading to prolonged effects and potential drug accumulation. Conversely, hydrophilic (water-soluble) drugs may distribute differently due to reduced total body water, which can result in higher plasma concentrations and a greater risk of side effects or toxicity.

These distribution changes combined with other factors, such as decreased kidney and liver function in older adults, can affect drug metabolism and excretion. Therefore, understanding how aging affects drug distribution is crucial for appropriate dosing and minimizing adverse effects in older patients.