How does paracetamol close PDA?

How Paracetamol Helps Close PDA in Newborns

Patent ductus arteriosus (PDA) is a common condition in premature infants where a blood vessel called the ductus arteriosus fails to close after birth. This can lead to serious heart and lung complications if left untreated. While ibuprofen and indomethacin have traditionally been used to close the PDA, paracetamol (also known as acetaminophen) has emerged as a promising alternative—especially in babies who don’t respond well to other treatments.

So how does paracetamol work in closing the PDA? The answer lies in its effect on prostaglandin synthesis. Prostaglandins are substances in the body that help keep the ductus arteriosus open during fetal life. After birth, a drop in prostaglandin levels normally allows the vessel to close. In preterm infants, however, prostaglandin activity remains high, keeping the ductus open.

Paracetamol inhibits the enzyme prostaglandin synthetase, which is responsible for producing prostaglandins. Although its exact mechanism is still debated, researchers believe it primarily targets the peroxidase component of this enzyme system. Interestingly, the peroxidase segment becomes active at much lower concentrations of peroxides than the cyclooxygenase (COX) segment—making it more sensitive to certain inhibitors like paracetamol. By disrupting prostaglandin production at this level, paracetamol effectively encourages the closure of the ductus arteriosus.

Compared to other medications, paracetamol has shown fewer side effects on the kidneys and gastrointestinal tract, making it a safer option for fragile newborns. Clinical studies have demonstrated success rates comparable to ibuprofen, with fewer complications.

While more research is ongoing, paracetamol’s role in managing PDA highlights how a common pain reliever can have powerful, targeted effects in neonatal care—offering hope and a gentler treatment path for premature babies and their families.