Crossover Clinical Trial, Randomized, Double Blind, Placebo Controlled Trial

Inclusion Criteria: * Patients willing and able to give informed consent for participation in the study * Ability to understand study procedures and to comply with it for the duration of the study. * Subjects of both sexes, the age range between 18 and 70 years old. * Serum uric acid above 7 mg / dl. * Estimated glomerular filtration rate by MDRD abbreviated formula less than 60 ml / min / 1.73 m2 and above 15 ml / min / 1.73 m2. * Stability of renal function (serum creatinine increase without exceeding 50% in the three months before the start of the study). * Clinically stable in terms of no hospitalizations of cardiovascular events in the 3 months before the study began. Exclusion Criteria: * Drop active in the 60 days prior to study initiation. * Use of allopurinol within 60 days preceding baseline * Active infections within 30 days prior to baseline. * Patients with systemic inflammatory disease * Infection with HIV, Hepatitis C and Hepatitis B. * History of cancer within 5 years prior to the first dose of study medication * Chronic liver disease. * Immunosuppressive therapy. * Pregnant women, breastfeeding or planning to become pregnant. * Allergy or sensitive to allopurinol. * Addiction to drugs or alcohol, in the opinion of the investigator, may interfere with compliance with study requirements. * Inability or unwillingness of the individual or legal guardian or representative to give written informed consent.