Paracetamol (Acetaminophen) for Patent Ductus Arteriosus: Where Do We Stand?

Trial of Selective Early Treatment of Patent Ductus Arteriosus with Ibuprofen

BACKGROUND

The cyclooxygenase inhibitor ibuprofen may be used to treat patent ductus arteriosus (PDA) in preterm infants. Whether selective early treatment of large PDAs with ibuprofen would improve short-term outcomes is not known.

METHODS

We conducted a multicenter, randomized, double-blind, placebo-controlled trial evaluating early treatment (≤72 hours after birth) with ibuprofen for a large PDA (diameter of ≥1.5 mm with pulsatile flow) in extremely preterm infants (born between 23 weeks 0 days' and 28 weeks 6 days' gestation). The primary outcome was a composite of death or moderate or severe bronchopulmonary dysplasia evaluated at 36 weeks of postmenstrual age.

RESULTS

A total of 326 infants were assigned to receive ibuprofen and 327 to receive placebo; 324 and 322, respectively, had data available for outcome analyses. A primary-outcome event occurred in 220 of 318 infants (69.2%) in the ibuprofen group and 202 of 318 infants (63.5%) in the placebo group (adjusted risk ratio, 1.09; 95% confidence interval [CI], 0.98 to 1.20; P = 0.10). A total of 44 of 323 infants (13.6%) in the ibuprofen group and 33 of 321 infants (10.3%) in the placebo group died (adjusted risk ratio, 1.32; 95% CI, 0.92 to 1.90). Among the infants who survived to 36 weeks of postmenstrual age, moderate or severe bronchopulmonary dysplasia occurred in 176 of 274 (64.2%) in the ibuprofen group and 169 of 285 (59.3%) in the placebo group (adjusted risk ratio, 1.09; 95% CI, 0.96 to 1.23). Two unforeseeable serious adverse events occurred that were possibly related to ibuprofen.

CONCLUSIONS

The risk of death or moderate or severe bronchopulmonary dysplasia at 36 weeks of postmenstrual age was not significantly lower among infants who received early treatment with ibuprofen than among those who received placebo. (Funded by the National Institute for Health Research Health Technology Assessment Programme; Baby-OSCAR ISRCTN Registry number, ISRCTN84264977.).

Early closure mechanisms of the ductus arteriosus in immature infants

AIM

According to experimental studies, cardiopulmonary distress decreases after closure of patent ductus arteriosus. However, early closure of the ductus using ibuprofen or indomethacin has failed to increase survival without serious morbidity. We review relevant data aiming to define optimal early management strategies that promote early closure of ductus arteriosus without serious adverse effects.

METHODS

Literature in English was searched selectively focusing on the potential of using acetaminophen for early closure of the ductus.

RESULTS

Prophylactic ibuprofen or indomethacin intended to close the ductus, predisposes infants to ischaemia, bleeding and immune dysfunction. Acetaminophen appears to have a similar efficacy as indomethacin or ibuprofen, and all three dose-dependently constrict the ductus. Ibuprofen and indomethacin cause non-specific inhibition of prostaglandin synthesis, while acetaminophen predominantly inhibits prostaglandin E synthesis. Owing to low CYP450 activity in infancy, acetaminophen toxicity has been rarely evident. However, increasing the dosage increases the oxidative stress. We review prophylactic treatments that may increase the safety and efficacy of acetaminophen. These include vitamin A, cysteine and glutamine, and low-dose corticosteroid supplementation.

CONCLUSION

The current challenge is to define a safe perinatal management practice that promotes cardiorespiratory adaptation in immature infants, particularly the seamless closure of the ductus before significant cardiopulmonary distress develops.

Intravenous acetaminophen (at 15 mg/kg/dose every 6 hours) in critically ill preterm neonates with patent ductus arteriosus: A prospective study

WHAT IS KNOWN AND OBJECTIVES

Acetaminophen has been increasingly used in treating patent ductus arteriosus (PDA) in preterm neonates. Variations were observed in the dosing regimen of acetaminophen across the studies. There is hardly any data available for a relatively higher dose of intravenous acetaminophen (15 mg/kg/dose every 6 hours) in the preterm population. We present here the results of a prospective study with this dose of intravenous acetaminophen for treating PDA in critically ill preterm neonates.

METHODS

Preterm neonates (≤37 weeks of gestational age) with haemodynamically significant PDA were enrolled. Intravenous acetaminophen at 15 mg/kg/dose every 6 hours was administered. Echocardiographic monitoring, liver and renal function tests were carried out. Standard definitions were adhered for defining acute kidney injury (AKI) and hepatotoxicity.

RESULTS

Fifty-five neonates were recruited. Following the first dose, less than half had their serum acetaminophen concentrations in the therapeutic range. Extreme preterm neonates were less likely to have a sustained therapeutic acetaminophen concentration after the first dose. Following multiple doses and at steady state, 97.2% and 98.8% respectively were in the therapeutic range. Forty-three (78.2%) neonates had successful closure of the ductus arteriosus of which 22 were extreme preterm, 17 were very preterm and 4 were late preterm neonates; and considering their birthweights, 21 were extremely low, 16 were very low and 6 were low birthweight categories. Ten neonates had elevated alanine aminotransferase levels with three in the low-to-moderate risk of hepatotoxicity category. Eight neonates had altered renal function tests indicating AKI.

WHAT IS NEW AND CONCLUSION

Intravenous acetaminophen at 15 mg/kg/dose every 6 hours was efficacious in 78.2% of the preterm neonates with PDA. We observed a lower incidence of hepatotoxicity, and AKI in the study population. No association was observed between the serum acetaminophen concentrations and PDA closure.

Predictors of successful patent ductus arteriosus closure with acetaminophen in preterm infants

OBJECTIVE

Evaluate predictors of successful PDA closure following acetaminophen treatment.

STUDY DESIGN

Retrospective cohort study of ≤30 weeks GA infants born from 1 January 2013-30 September 2019, and treated with single course acetaminophen by symptomatic PDA treatment strategy. Multiple maternal and neonatal variables were identified as potential predictors. Univariate analysis and multivariable regression models were applied to evaluate the strongest predictors.

RESULTS

Sixty-six patients were included, 28 (42.4%) had successful PDA closure following acetaminophen. Success was associated with GA > 26 weeks (65% vs. 33%, AUC = 0.64), birthweight >750 g (53% vs. 32%, AUC = 0.61), PDA size ≤0.2 cm (63% vs. 32%, AUC = 0.64), and no prior indomethacin use (56% vs. 33%, AUC = 0.61). Multivariable model identified GA > 26 weeks (RR = 1.92, CI 1.20-3.09) and PDA size ≤0.2 cm (RR: 1.82, CI 1.11-2.98) as the strongest predictors.

CONCLUSION

Acetaminophen may be more successful in targeted PDA closure in >26 weeks GA infants with PDA size ≤0.2 cm.