A 6-year-old child undergoes tonsillectomy for obstructive sleep apnea. The parents ask about using codeine for postoperative pain. Codeine is specifically contraindicated in this scenario because:
- A Codeine causes excessive bleeding after tonsillectomy
- B Codeine causes post-tonsillectomy airway edema
- C Ultra-rapid CYP2D6 metabolizers can convert codeine to morphine rapidly, causing fatal respiratory depression, especially with underlying sleep apnea ✓
- D Codeine is ineffective for post-tonsillectomy pain because it is a prodrug
Correct answer: C. Ultra-rapid CYP2D6 metabolizers can convert codeine to morphine rapidly, causing fatal respiratory depression, especially with underlying sleep apnea
Explanation
Codeine is a prodrug activated by CYP2D6 to morphine. Ultra-rapid metabolizers produce morphine rapidly and unpredictably, risking overdose and fatal respiratory depression. This risk is amplified in children with obstructive sleep apnea due to compromised airway tone. The FDA has issued a black box warning against codeine use in children under 12 after tonsillectomy or adenoidectomy.
Reference: Katzung Basic and Clinical Pharmacology, 15th ed.
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Written and medically reviewed by the StethoPrep medical team.