A 59-year-old man with a known history of small cell lung carcinoma, currently undergoing chemotherapy, presents to the emergency department with a 3-day history of progressive confusion, headache, and two witnessed generalized tonic-clonic seizures. His wife reports he has had no vomiting or excessive fluid intake. Vital signs show blood pressure 128/76 mmHg, heart rate 88/min, respiratory rate 16/min, and temperature 37.1°C. Physical examination reveals no peripheral edema, normal skin turgor, and moist mucous membranes consistent with euvolemia. Laboratory testing shows serum sodium 116 mEq/L, serum osmolality 242 mOsm/kg, urine osmolality 520 mOsm/kg, and urine sodium 45 mEq/L. After a trial of strict fluid restriction fails to correct the hyponatremia, he is started on a medication that antagonizes vasopressin V2 receptors in the collecting duct. Which of the following drugs was most likely prescribed?
- A)TolvaptanGABARITO
- B)Hydrochlorothiazide
- C)Desmopressin
- D)Spironolactone
- E)Mannitol
Explicação
Tolvaptan is a vasopressin V2 receptor antagonist used in selected cases of euvolemic or hypervolemic hyponatremia, including SIADH. Blocking V2 signaling reduces aquaporin insertion in the collecting duct and promotes free water excretion. The small cell lung... Ver explicação completa e trilha adaptativa →