Tetracyclines are contraindicated in children under 8 years and in pregnancy. The reason for this restriction is:
- A Grey baby syndrome due to immature hepatic glucuronidation
- B Chelation of calcium with deposition in developing bones and teeth causing permanent discoloration and inhibition of bone growth ✓
- C Hemolytic anemia in G6PD-deficient children
- D Renal tubular acidosis in immature nephrons
Correct answer: B. Chelation of calcium with deposition in developing bones and teeth causing permanent discoloration and inhibition of bone growth
Explanation
Tetracyclines chelate calcium and deposit in calcifying tissues (bones and teeth) during active growth phases. In teeth, this causes permanent yellow-brown discoloration (fluorescence under UV light) and weakening of enamel. In bones, it inhibits linear growth. Grey baby syndrome is caused by chloramphenicol. Hemolytic anemia with antimalarials/sulfonamides occurs in G6PD deficiency. These effects are irreversible, hence the absolute contraindication during tooth and bone development periods.
Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.