Vasopressin-induced hyponatremia in a patient with pulmonary hypertension and right heart failure treated for septic shock

We report a case of a 55-year-old woman who developed hyponatremia after the initiation of exogenous vasopressin to treat vasodilatory shock. Discontinuation of exogenous vasopressin therapy, without any other changes in medical therapy or the patient’s condition, led to a rapid correction in the serum sodium level along with a marked increase in urine output. Increased free water retention due to exogenous vasopressin administration may have contributed to hyponatremia in this patient. This case illustrates the potential for vasopressin to have potent and unintended renal and electrolyte effects in patients treated for vasodilatory shock.