ADME-tox issues for the elderly

Background: The elderly, defined as people aged > 65 years, are a heterogeneous population. With increasing age there is increased prevalence of disease for which medication may be indicated and increased drug toxicity. Objective/methods: This review of the published scientific and clinical data on absorption, distribution, metabolism, excretion and toxicity (ADME-tox) in old age informs prescribers and drug developers of age-related factors that determine drug dose, safety and efficacy. Results/conclusion: Increased inter-individual variability is a major feature of toxicology in old age. Changes in ADME-tox associated with normal ageing are currently better described than changes in the frail aged. Reduced hepatic and renal clearance are the most significant toxicokinetic changes seen in normal ageing. Drug toxicity in old age is influenced by changes in the quantity, affinity and responsiveness of drug targets, physiologic reserve and response to injury. Further investigation of the effects of medications on cognitive and physical functions in older adults is required.