 Finally, the pharmacogenetic study is focused on characterization of polymorphisms of candidate genes associated to development of metabolic side effects of diuretics, to help understanding of mechanisms underlying these adverse events. This kind of information will help to prevent the occurrence of adverse events by the use of adeguate combination treatment, thus resulting in the further reduction of the cost of antihypertensive treatment due to the reduction of the number of patients that discontinue therapy for occurrence of adverse events. 