Endocrine Pharmacology USMLE Step 1 Practice Question
A 14-year-old boy presents with polyuria and polydipsia following a traumatic brain injury sustained in a motor vehicle accident three days ago. Vital signs show HR 92 bpm, BP 118/76 mmHg, RR 16, temp 37°C. Physical examination reveals dry mucous membranes. Serum sodium is 148 mEq/L, serum osmolality is 305 mOsm/kg, and urine osmolality is 210 mOsm/kg. Water deprivation testing shows minimal change in urine osmolality. However, after administering an intranasal ADH analog at a dose of 10 mcg, urine osmolality increases substantially to 580 mOsm/kg. No hyperglycemia is present. Which drug was administered?
Answer choices
- AHydrocortisone
- BDesmopressinCorrect answer
- CTolvaptan
- DDemeclocycline
- EOxytocin
- FVasopressin
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