Effects of aging on pharmacokinetic and pharmacodynamic drug processes

Aging affects the pharmacokinetics and pharmacodynamics of drugs, which has potentially important implications for the use of psychotropic medication in older adults. The absorption of orally administered drugs may be impaired or delayed, the volume of distribution of most drugs is decreased, and over time, the distribution shifts toward greater drug accumulation in fat stores. Decrease in renal function with age is especially important regarding the use of lithium but is also relevant for most drugs because they are eventually cleared through the kidneys after metabolism in the liver. Because pharmacodynamic changes associated with aging will make elderly patients more sensitive to the pharmacological effects of medication-especially adverse effects-nurses should be appropriately trained in pharmacology and therapeutics in older adults.