[The kidneys and old age].

With more detailed knowledge on renal function at advanced age it became clear that age-related changes of renal function are less severe than previously thought. However, these changes are significantly aggravated by classical cardiovascular risk factors such as hypertension, diabetes and smoking. As a consequence, in elderly with such co-morbidity the appearance of a primary kidney disease or acute renal failure may cause a serious deterioration of renal function. In addition, impaired homeostasis with respect to salt (and fluid) balance has important consequences for the management of the elderly who is exposed to the twin risks of dehydration and fluid overload. Finally, the kidney is the main route of excretion for many drugs and their active metabolites. Diminution of renal function with age underlies, at least in part, the known predisposition of the elderly to side effects of their medication such as non-steroidal anti-inflammatory drugs.