A new publication by Afif El-Khuffash and his colleagues (El-Khuffash A et al. Efficacy of paracetamol on patent ductus arteriosus closure may be dose dependent: evidence from human and murine studies. Pediatr Res. 2014;76(3):238-44) describes a retrospective review of paracetamol use in newborn infants, and an in vitro study using mouse ductal tissue. The clinical part of the paper shows that with a short course of oral paracetamol there was no response, with a longer course of oral paracetamol there were some responses, and with intravenous paracetamol for between 2 and 6 days there were many PDA closures, and others that tended to constrict. The numbers are very small but suggestive.
Afif also reports the effects of paracetamol and indomethacin on preterm and term mouse ductal tissue. Paracetamol had no effect on the preterm, and lesser effect on the term, compared to indomethacin. With high enough concentrations of paracetamol there were indeed constrictive responses to paracetamol.
This all suggests that it is indeed possible that paracetamol might be effective. But I won’t be expecting miraculous results.
This is also the suggestion of an article from Israel (Nadir E, Kassem E, Foldi S, Hochberg A, Feldman M. Paracetamol treatment of patent ductus arteriosus in preterm infants. J Perinatol. 2014;34(10):748-9), 7 extremely preterm infants with large PDA were treated, they either had failed ibuprofen or had a contra-indication. Most closed without surgery. Again suggestive but no more than that.
Presumably there are placebo controlled trials coming, I hope so.