Severe symptomatic hyponatremia--an uncommon presentation of tacrolimus nephrotoxicity.

Though tacrolimus-induced nephrotoxicity and hyperkalemia are well known, severe symptomatic hyponatremia is not commonly documented with its use. Here, we report a case of severe symptomatic hyponatremia in a renal transplant recipient on tacrolimus despite normal tacrolimus trough level. All other potential causes of hyponatremia were ruled out in this patient. This case highlights an uncommon aspect of tacrolimus nephrotoxicity, which we should keep in mind while following up a renal transplant recipient.