Painkillers in Preterm Infants: Do Acetaminophen and NSAIDs Raise the Risk of Chronic Lung Disease?

One of the most persistent questions in neonatal medicine has just been sharpened by a new analysis of data from one of the largest trials ever conducted on the treatment of patent ductus arteriosus, the fetal blood vessel that fails to close in many extremely preterm infants. Writing in Pediatric Research, Rakesh Sharma and Vineet Bhandari of the Children’s Regional Hospital at Cooper, Cooper Medical School of Rowan University, examine whether the drugs most commonly used to close the ductus, acetaminophen and the non-steroidal anti-inflammatory drugs ibuprofen and indomethacin, might themselves influence the risk of bronchopulmonary dysplasia, the chronic lung disease that remains one of the most feared outcomes of extreme prematurity. Their commentary accompanies a secondary analysis of the BeNeDuctus trial by Hoornenborg and colleagues, which looked specifically at paracetamol, the international name for acetaminophen, given as an analgesic and its association with bronchopulmonary dysplasia in extremely preterm infants.

The clinical stakes are considerable. Bronchopulmonary dysplasia, defined by the need for supplemental oxygen or respiratory support at a corrected gestational age of thirty-six weeks, affects a substantial proportion of infants born before twenty-eight weeks of gestation and is associated with long-term respiratory morbidity, neurodevelopmental impairment, and rehospitalization throughout childhood. Its pathogenesis is multifactorial, involving inflammation, infection, hyperoxia exposure, impaired alveolar and vascular development, and genetic and environmental interactions. Because no single therapy has proven reliably protective, clinicians scrutinize every drug that reaches the developing lung for possible harm, and the analgesics and anti-inflammatory agents used in the first weeks of life are no exception.

The story of these drugs in the neonatal intensive care unit begins with the ductus arteriosus itself. Increased blood flow across a patent ductus arteriosus can be associated with increased pulmonary blood circulation and morbidity, a hemodynamic burden that physicians have tried to relieve since the latter part of the twentieth century by closing a hemodynamically significant ductus in the hope of improving outcomes. The pharmacological workhorses of that effort have been cyclooxygenase inhibitors, chiefly indomethacin and ibuprofen, which reduce prostaglandin signaling and allow the vessel to constrict and close. Both drugs have been used extensively for ductal closure, but both carry side effects and safety concerns in preterm infants, including effects on renal perfusion, gastrointestinal integrity, and platelet function, concerns that have driven a decades-long search for alternatives.

That search produced one of the more memorable accidental discoveries in modern neonatology. As recounted by Sharma and Bhandari, Hammerman and colleagues observed that the use of acetaminophen in preterm infants led to closure of the patent ductus arteriosus, a finding reported in case series that surprised many observers. The mechanism is plausible: acetaminophen acts on prostaglandin synthesis through pathways distinct from classical cyclooxygenase inhibition, and the ductus in the preterm infant remains sensitive to even modest reductions in prostaglandin activity. Following those initial case reports, multiple trials demonstrated that acetaminophen was as effective in closing the ductus as the two established non-steroidal anti-inflammatory drugs, ibuprofen and indomethacin. Crucially, those studies did not look only at closure rates; they also examined associated morbidities, and bronchopulmonary dysplasia emerged as the outcome of greatest interest.

The evidence on that outcome, however, has been reassuringly consistent so far. A large multicenter trial conducted by Gupta and colleagues, published in the New England Journal of Medicine, showed no significant difference in the incidence of bronchopulmonary dysplasia between groups of infants treated with ibuprofen and those given placebo. A retrospective study by Jensen and colleagues compared one group of infants receiving acetaminophen with another receiving ibuprofen or indomethacin and found that the incidence of death or grade 2 to 3 bronchopulmonary dysplasia was similar in both groups. These findings suggested that neither class of drug, when used for ductal closure, clearly worsens the risk of chronic lung disease, at least within the populations and dosing regimens studied.

The BeNeDuctus trial added an important dimension to this debate. This large multicenter randomized non-inferiority trial compared expectant management of a significant patent ductus arteriosus, meaning careful observation without immediate drug treatment, against early treatment with ibuprofen. The trial showed no difference in the incidence of bronchopulmonary dysplasia, necrotizing enterocolitis, or death between the two management strategies. That result was consequential in its own right, because it suggested that routine early pharmacological closure of the ductus may not be necessary for all affected infants. But it also created an unexpected opportunity: some patients in both subgroups received acetaminophen, not for ductal closure but for analgesia, meaning the trial inadvertently enrolled a cohort of extremely preterm infants exposed to the drug for reasons unrelated to their ductus.

Hoornenborg and colleagues exploited that opportunity in their secondary analysis, asking whether paracetamol given as an analgesic was associated with an increased risk of bronchopulmonary dysplasia in extremely preterm infants. The question matters because acetaminophen is among the most widely administered medications in neonatal intensive care, used for procedural and postoperative pain and increasingly considered for ductal closure. If the drug carried even a modest risk to the developing lung, the population-level consequences could be substantial given how many preterm infants receive it. Sharma and Bhandari frame their commentary around exactly this tension between therapeutic utility and pulmonary safety.

Concern about acetaminophen’s effects on the lung is not merely theoretical. Laboratory studies referenced in the commentary have shown that toxic acetaminophen exposure can induce distal lung endoplasmic reticulum stress, proinflammatory signaling, and emphysematous changes in the adult murine lung, and that the developing murine lung appears susceptible to acetaminophen toxicity in ways independent of the hepatic damage for which the drug is best known. Investigators have also raised the possibility that acetaminophen exposure in early life could have lifelong consequences for respiratory health. On the other side of the ledger, ibuprofen has its own pulmonary profile: animal work has documented vascular and pulmonary effects of ibuprofen on neonatal lung development, and recent studies indicate that inhibition of the mitochondrial integrated stress response can ameliorate ibuprofen-induced endothelial dysfunction in models of neonatal hyperoxia-induced lung injury. Both drug classes, in other words, have biological plausibility for lung effects that clinical trials have so far not translated into clear harm.

Interpreting this literature requires attention to the difficulty of the outcome itself. Bronchopulmonary dysplasia is now understood as a syndrome with multiple pulmonary phenotypes in the preterm infant, and its diagnosis has been refined through evidence-based approaches that grade severity by the level of respiratory support required. Newer tools, including magnetic resonance imaging phenotyping and life-course approaches to lung function monitoring after preterm birth, are reshaping how researchers detect subtle drug effects that survival-based or oxygen-based definitions may miss. The commentary’s authors, who have previously argued that bronchopulmonary dysplasia research must move from the bedside to the bench and back again, emphasize that postnatal inflammation, corticosteroid effects on lung development, and gene-environment interactions all complicate any attempt to isolate the contribution of a single analgesic or anti-inflammatory drug.

Where does this leave clinicians and families? The accumulating trial evidence, from the Gupta ibuprofen trial, the Jensen retrospective comparison, the BeNeDuctus trial, and now the Hoornenborg secondary analysis, points toward a consistent conclusion: neither acetaminophen nor the classical non-steroidal anti-inflammatory drugs, as used in contemporary neonatal practice, has been shown to increase the incidence of bronchopulmonary dysplasia or death in extremely preterm infants. At the same time, Sharma and Bhandari’s commentary underscores that the question of pulmonary safety has not been closed as definitively as the ductus itself. Preclinical signals of lung toxicity, the heterogeneity of bronchopulmonary dysplasia phenotypes, and the possibility of long-term respiratory consequences all argue for continued vigilance. As randomized trials of prophylactic acetaminophen for ductal closure and expectant management strategies continue to mature, the developing lung remains the outcome against which every neonatal drug must ultimately be judged.

Subject of Research: Pulmonary safety of acetaminophen and NSAID treatment for patent ductus arteriosus in preterm infants

Article Title: Does use of acetaminophen and/or NSAIDs increase the risk of developing bronchopulmonary dysplasia?

Article References: Sharma, R., & Bhandari, V. (2026). Does use of acetaminophen and/or NSAIDs increase the risk of developing bronchopulmonary dysplasia?. Pediatric Research. https://doi.org/10.1038/s41390-026-05526-y

Image Credits: AI Generated

DOI: 10.1038/s41390-026-05526-y

Keywords: bronchopulmonary dysplasia, acetaminophen, NSAIDs, patent ductus arteriosus, preterm infants, BeNeDuctus trial, neonatology, ibuprofen, indomethacin, Pediatric Research, lung development, neonatal intensive care