[Rational drug use: an economic approach to decision making].

The present article approaches rational drug use (RDU) from the economical point of view. The implementation of RDU implies in costs and involves acquisition of knowledge and behavioral changes of several agents. The difficulties in implementing RDU may be due to shortage problems, information asymmetry, lack of information, uncertain clinical decisions, externalities, time-price, incentives for drug prescribers and dispensers, drug prescriber preferences and marginal utility. Health authorities, among other agencies, must therefore regularize, rationalize and control drug use to minimize inefficiency in pharmaceutical care and to prevent exposing the population to unnecessary health risks.