The absorption, action, and metabolism characteristics of drugs change in older adults due to factors including the normal process of aging and the impacts of disease on organ functions. Changes in the profile and proportions of drug use among older adults increase with increases in the severity of functional decline and the prevalence of chronic diseases. Drugs that are classified as “potentially inappropriate medications” (PIMs) carry a higher risk of causing adverse reactions in older adults, provide uncertain therapeutic benefits, or may be substituted by alternative drugs that are generally safer to use. Researchers have developed criteria for PIMs in geriatric medicine that are applicable to clinical practice and research. This article introduces the development and application of the PIMTaiwan criteria to help nurses better understand the current knowledge related to medication use among older adults and the results of related research in Taiwan.