Indomethacin (Patent Ductus Arteriosus)

How it works

It inhibits cyclo-oxygenase, reducing prostaglandin synthesis; the resulting fall in prostaglandin E2, which normally maintains ductal patency, promotes constriction and closure of the ductus arteriosus.

Prescribing in practice

• Contraindicated in active bleeding, significant thrombocytopenia, necrotising enterocolitis and significant renal impairment, as indomethacin can precipitate bleeding, gut and renal complications.
• It reduces renal, mesenteric and cerebral blood flow, so monitor urine output and watch for signs of gastrointestinal or renal compromise.
• Prescribe according to a children's formulary and the SPC; a repeat course may be considered if the duct fails to close.

Monitoring

Monitor renal function, urine output, platelet count and for signs of gastrointestinal bleeding, alongside echocardiographic assessment of ductal status.

Counselling the patient

• Explain to parents that the medicine is being used to help close a blood vessel that should have closed after birth, avoiding surgery in many cases.
• The neonatal team will closely monitor the baby's kidneys, urine output and blood counts during treatment.
• Surgical closure may still be needed if the medicine does not work or cannot be used.

Evidence & guidelines

Indomethacin is an established option for pharmacological ductal closure, with trials also supporting prophylactic use for intraventricular haemorrhage in very preterm infants, though benefit on long-term outcomes is uncertain.