Adverse drug reactions among the elderly: a reassessment.

The elderly are widely believed to be predisposed to adverse drug reactions, chiefly because of the large quantities of drugs they consume, combined with the effects of aging on distribution, metabolism, and the patterns of drug usage. These beliefs affect the physician's prescribing behavior. To study the validity of these concepts, the supporting medical literature was reviewed. Existing studies of the rates of adverse drug reactions have several methodologic limitations, including inadequate control for disease severity, the use of calculation denominators which overestimate incidence, and dependence upon definitions of medication error rates which do not adequately reflect the potential for adverse outcome. Further studies are needed for clarification of drug-use patterns and problems among the elderly.