Management of hyponatremia associated with acute porphyria-proposal for the use of tolvaptan.

Hyponatremia is a common feature during the neurovisceral acute attacks which characterize hepatic porphyrias, as well as a sign of its severity. Therapeutic options for first-line acute attacks are intravenous administration of glucose and/or exogenous heme. The former treatment can aggravate hyponatremia by dilution and cause seizures; thus, the correction of hyponatremia must be carried out with extreme caution.