What pharmacologic agents are commonly used to close a PDA in neonates, and what are two major contraindications?

• A. Dexamethasone; Contraindications: severe infections
• B. Indomethacin or ibuprofen; Contraindications: significant renal dysfunction and active bleeding/peptic ulcer disease or NEC risk
• C. Epinephrine; Contraindications: hypertension
• D. Acetaminophen; Contraindications: liver disease

Answer: (B)

Prompt closure in premature infants relies on blocking prostaglandin synthesis. Indomethacin or ibuprofen are the drugs most commonly used because they inhibit cyclooxygenase, which lowers prostaglandin E2 levels that keep the ductus arteriosus open. With prostaglandin reduction, the ductus constricts and can close, especially when treatment is started early in the PDA course.

Two major reasons these NSAID agents are avoided in certain babies are significant renal dysfunction and risk of serious GI bleeding or NEC. NSAIDs can reduce renal perfusion and worsen kidney function, which is especially dangerous in fragile neonates. They also impair platelet function and can cause GI irritation, increasing the risk of bleeding, peptic ulcers, or necrotizing enterocolitis. When these contraindications are present, alternative approaches—such as acetaminophen-based closure in some centers or surgical ligation—may be considered.