A premature neonate given prophylactic chloramphenicol develops vomiting, ash-gray cyanosis, hypothermia, and cardiovascular collapse within days. The underlying reason for this syndrome is:

• A Immature renal tubular secretion causing accumulation of inactive metabolites
• B Deficient hepatic UDP-glucuronyl transferase leading to toxic drug accumulation ✓
• C Chloramphenicol-induced hemolysis from erythrocyte G6PD deficiency
• D Displacement of bilirubin from albumin causing kernicterus

Explanation

Gray baby syndrome results from inadequate glucuronidation of chloramphenicol in the newborn liver, especially in preterm infants whose UDP-glucuronyl transferase is immature, combined with poor renal excretion of the unconjugated parent drug. Free chloramphenicol accumulates and blocks mitochondrial electron transport in myocardium, producing circulatory collapse. Hemolysis relates to nitrofurantoin and primaquine, and kernicterus relates to sulfonamide displacement of bilirubin.

Reference: Katzung Basic and Clinical Pharmacology, 15th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.