Acetaminophen in low doses for closure of the ductus arteriosus of the premature

Objective: The objective of the study is to report the experience with acetaminophen in low doses as an alternative to the treatment of the ductus arteriosus of the preterm newborn. Materials and Methods: Retrospective study including preterm newborns with patent ductus arteriosus who received oral acetaminophen because treatment with indomethacin had failed or is contraindicated. A dosage consisted of a first dose of 25 mg/kg and maintenance doses of 30 mg/kg/day, for 3 to 7 days. A second cycle was administered in cases of reopening of the ductus arteriosus. The rates of ductal closure and surgery were calculated. Patients were categorized into responder and nonresponder groups for acetaminophen, and the average values of ductal diameter, weight, gestational age, and postnatal age were compared. Results: Eighty-seven preterm newborns, with a postnatal age from 3 to 27 days, with average values of ductus arteriosus equal to 2.5 ± 0.8 mm/kg, gestational age 27.2 ± 1.9 weeks, and birth weight 888.9 ± 241 g, received acetaminophen for 3 to 7 days. A second cycle was administered in 15 preterm newborns. The ductus closure rate, after one or two cycles, was 74.7%, and the recommendations for surgical closure were progressively reduced from 50% in the 1st year to 6.2% in the past year. Lower ductal closure rate occurred in the group of newborns with the lowest average weight (P = 0.018), the highest average ductal diameter (P = 0.002), and the lowest average gestational age (P = 0.09). Postnatal age at the start of acetaminophen use was shown to be irrelevant regarding the treatment (P = 0.591). Conclusions: Acetaminophen in low doses showed to be an effective alternative for the closure of the ductus arteriosus for preterm newborns in whom treatment with indomethacin or ibuprofen failed or was contraindicated.