Pharmacology and Aging

The elderly use more drugs than younger people, and often require multiple drugs, with the potential for drug interactions and adverse drug reactions. It is not known to what extent age per se may predispose to drug interactions. Furthermore, the toxicology of drugs in the elderly has received almost no systematic investigation. For example, are the elderly more susceptible than the young to the hepatotoxic effects of some drugs? Epidemiologic studies using standardized methodology, such as the Defined Daily Dose, are needed to compare drug utilization in both ambulatory and institutionalized elderly between countries and regions. This will provide the basis for the evaluation of the effects of educational programs aimed at promoting rational drug therapy in the elderly. Analysis of the differences on drug use and drug prescribing patterns in various countries may yield insight into the determinants of those patterns and suggest optimal educational approaches. Available evidence indicates that age‐related alterations in the physiology of drug distribution, drug elimination, and drug action are the substrata upon which disease‐related alterations in drug disposition and drug response are superimposed. Continued efforts to characterize these age‐related and disease‐related effects are needed. At present, generalizations are difficult because of conflicting data. Greater attention to subject selection, environmental factors, such as smoking and diet, and protocol design is necessary. As much as possible, research protocols should attempt to simulate the actual clinical use of the drug under study. This often means conducting studies at steady state after multiple dosing rather than only after a single dose. A longitudinal study using model compounds would be of great interest to help distinguish the effects of aging per se from those of disease. Wherever possible, pharmacodynamic studies should be combined with studies of pharmacokinetics. Gaps in our knowledge exist for all drug classes. Continued basic research in pharmacology and physiology is required to elucidate the mechanisms for the age differences observed in clinical studies. This research depends on the use of animal and in vitro model systems. Efforts to define the optimal animal or in vitro model(s) for human geriatric pharmacology are obviously important components of this basic research. Although compliance with therapeutic regimens is not necessarily worse in the elderly than in younger age groups, the consequences of errors in self medication may be more severe. Thus, further efforts are needed to develop ways of enhancing the comprehension and compliance of geriatric patients.