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Indomethacin when given beyond 36 weeks what will happen?
Indomethacin when given beyond 36 weeks what will happen?
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Recall which molecules maintain patency of the ductus arteriosus and what indomethacin does to their synthesis.
Updated On: Jun 23, 2026
- Premature closure of PDA
- Still birth
- No effect
- Teratogenic
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The Correct Option is A
Solution and Explanation
Pharmacology of Indomethacin: Indomethacin is a non-selective COX inhibitor that blocks prostaglandin synthesis.
$\text{PGE}_2$ and $\text{PGI}_2$ (prostacyclin) maintain patency of the ductus arteriosus (DA) in fetal life through vasodilation. When these prostaglandins are inhibited by indomethacin after 36 weeks, the DA undergoes premature constriction -- i.e., $\textbf{premature closure of PDA}$.
Clinical uses of this mechanism:
- Indomethacin is used therapeutically to close a symptomatic PDA in $\textbf{preterm neonates}$.
- As a tocolytic (stops preterm labour) it is used before 32 weeks; after 36 weeks it risks premature DA closure.
Why not teratogenic? Teratogenicity implies structural birth defects caused during organogenesis (first trimester). Indomethacin's fetal effects are pharmacodynamic (prostaglandin inhibition), not teratogenic.
\[\boxed{\text{Premature closure of PDA}}\]
$\text{PGE}_2$ and $\text{PGI}_2$ (prostacyclin) maintain patency of the ductus arteriosus (DA) in fetal life through vasodilation. When these prostaglandins are inhibited by indomethacin after 36 weeks, the DA undergoes premature constriction -- i.e., $\textbf{premature closure of PDA}$.
Clinical uses of this mechanism:
- Indomethacin is used therapeutically to close a symptomatic PDA in $\textbf{preterm neonates}$.
- As a tocolytic (stops preterm labour) it is used before 32 weeks; after 36 weeks it risks premature DA closure.
Why not teratogenic? Teratogenicity implies structural birth defects caused during organogenesis (first trimester). Indomethacin's fetal effects are pharmacodynamic (prostaglandin inhibition), not teratogenic.
\[\boxed{\text{Premature closure of PDA}}\]
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