Aging affects the toxicokinetics of substances, leading to alterations in absorption, distribution, metabolism, and excretion. For instance, decreased gastric motility and blood flow can affect drug absorption. Additionally, increased body fat and decreased lean body mass can influence drug distribution, potentially leading to prolonged half-lives of fat-soluble substances. The liver, a primary site for drug metabolism, often shows reduced function with age, impacting the metabolism of various drugs. Moreover, renal clearance tends to decline, affecting the excretion of many toxicants.
