IntroductionHaemodynamically significant patent ductus arteriosus increases morbidity-mortality rates in premature newborns. ObjectiveTo determine the incidence of patent ductus arteriosus in our population, as well as the closure rates of success and failure with ibuprofen and other related causes for failure. Materials and methodsA retrospective study was conducted on of 42 patients treated with one or 2 cycles of ibuprofen for patent ductus arteriosus closure from June 2011 to October 2012 at Instituto Nacional de Perinatología, Mexico City. The initial dosage was10mg/kg/day, and 2 additional doses of 5mg/kg/day. ResultsThere were 64 cases out of 295 admissions. Age at diagnosis: 5.0 days (±3.1); age at beginning of treatment: 5.3 days (±5.6). Rate of success for first cycle: 47.7%. If a second cycle was necessary the age at treatment was 9 days (±2.9), the success rate was 42.8% and the failure rate was 57.1%. If surgical closure was necessary, treatment was administered at 19.1 days (±7). Four patients (6%) developed acute renal failure associated with the use of ibuprofen. ConclusionsThere were no statistical differences in the rate of success for the closure of patent ductus arteriosus with the first or second cycle of ibuprofen (47.7% vs 42.8%) (p=1). With ibuprofen dosages actually used, the success rate for the closure of PDA is less with the second cycle than with the first one, but is not significant. There were no differences as regards IV fluids, neonatal sepsis, mechanical ventilation, or diuretics. Starting treatment after the 5th day is associated with an increase in the failure rate.