[Drug use in the elderly. Multiple diseases in the aged and therapeutic management: avoidable pitfalls].

CAUSE OF UNDESIRABLE EFFECTS: The normal aging process leads to homeostatic changes and modified absorption, distribution and elimination of drugs. Elderly subjects are thus more exposed to undesirable drug effects. In addition, the presence of multiple diseases, multiple drugs, dependency, and certain social and behavioral factors act together to potentialize the generation of side effects. PREDICTABLE RISKS: Accidents can result from drug-drug or drug-disease interactions. Subjects at risk can be identified using the concept of fragility. POSSIBLE PREVENTION: Practical guide-lines have been established by expert groups and should be used to avoid inadequate use of drug therapies.