Mirtazapine associated with profound hyponatremia: Two case reports

Conclusions: The likelihood of mirtazapine use causing hyponatremia in these 2 cases was “probable” according to criteria of the Naranjo Adverse Drug Reaction Probability Scale (score, 6). A review of published cases found that mirtazapine-associated hyponatremia occurred in patients aged >60 years, after a mean of 6.5 days and with doses as low as 7.5 mg daily. The mean sodium nadir was 117.2 mEq/L, but after stopping mirtazapine, the mean time to recovery was 11 days. Clinicians should be aware of the possibility of this reaction in elderly patients and should monitor sodium levels in high-risk patients if symptoms suggestive of hyponatremia develop.