[Properties of drug complications in elderly patients].

Adverse reactions to drugs are characteristically more frequent and more severe in elderly people as a result of factors that are found exclusively in this category of patients, such as multiple diseases, multiple medications, multiple prescribers, self-medication, age-related changes in pharmacokinetics and patient's compliance. Clinically, these reactions are atypical, often mixed, and they may take their symptoms from some other disease decompensated by the adverse reaction. The frequency of this iatropathology in elderly patients is such that it must systematically be suspected in the presence of any pathological episode.