Carbamazepine-induced hyponatremia
Drug-induced hyponatremia is commonly associated with diuretics (frusemide, indapamide), selective serotonin reuptake inhibitors (sertraline, fluoxetine) and antiepileptics.[1] A 61-year-old female, 38 kg, was scheduled for debridement and superficial skin grafting for post-burn raw area in right arm. History and physical examination was unremarkable. Blood biochemistry was normal except for serum electrolytes; Na 128 mEq/L, K 4.3 mEq/L. The patient denied any recent history of diarrhoea or vomiting that could explain the low sodium. Repeat investigation was consistent with hyponatremia; serum Na 129 mEq/L. On close persistent questioning the patient admitted that she suffered from epilepsy and was taking carbamazepine regularly for the last 34 years. She had sustained burns during an epileptic fit. Her oral intake of salt was increased and fluid intake was restricted. On the day of surgery, serum electrolytes were normal (Na 142 mEq/L, K 4.1 mEq/L). Standard general anesthesia (thiopentone, fentanyl, midazolam, vecuronium with controlled ventilati...