A patient undergoing induction of labor with oxytocin infusion develops nausea, vomiting, confusion, and seizures. Her serum sodium is 120 mEq/L. What is the underlying mechanism of this complication?
- A Direct neurotoxic effect of oxytocin
- B Water intoxication due to antidiuretic hormone-like effect ✓
- C Hypersensitivity reaction
- D Hypertensive encephalopathy
Correct answer: B. Water intoxication due to antidiuretic hormone-like effect
Explanation
Oxytocin has an antidiuretic hormone (ADH)-like effect when administered in high doses or over prolonged periods, especially with hypotonic fluids. This causes water retention, dilutional hyponatremia, and water intoxication, leading to seizures and confusion. Direct neurotoxicity or hypertension does not explain the severe hyponatremia.
Reference: Goodman and Gilman's The Pharmacological Basis of Therapeutics, 14th ed.
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