World population is getting older as a result of improvements in health care services and the reduction of the birth rate. Accordingly, diseases of elderly are becoming one of the most important subjects of health care and rates of drug use by this group, which is higher than the general population, have been increasing. Pharmacokinetic-pharmacodynamic changes that occur with aging should be taken into consideration during the planning of treatment in elderly. According to World Health Organization estimations, more than 50 % of medicines worldwide are improperly prescribed, provided or sold. Furthermore, half of the patients do not use their drugs correctly. Considering that 90 % of people above sixty-five years of age has at least one chronic disease, 60 % of them uses at least one drug and one-third of all prescribed medicines, a better implementation of rational drug use (RDU) principles in this age group will provide more “effective, safe and suitable” treatment so that the quality of life and compliance to treatment of patients will improve; drug interactions, adverse event incidence and treatment costs will be reduced.

Keywords: RDU, geriatrics, polypharmacy, drug interaction