Department of Psychiatry 1, Paracelsus Private Medical University, Salzburg, Austria.
Int J Psychiatry Clin Pract. 2006;10(1):17-26. doi: 10.1080/13651500500410216.
Hyponatremia, defined as serum sodium below 135 mmol/l, is a potentially life-threatening condition and was shown to be more frequent in elderly and psychiatric patients. In the last years numerous case reports on SSRI- and venlafaxine-induced hyponatremia were published indicating a higher incidence than previously thought. Only few studies have been performed and the incidence reported varies widely from 4.6/1000 people to 25%. It is still unclear if any single SSRI shows a higher incidence of hyponatremia than the others. Some data suggest that venlafaxine may have a stronger association to hyponatremia than SSRIs. Risk factors include age, female sex, low body mass index, severe physical illness, history of former hyponatremia and co-medications known to induce hyponatremia, especially thiazide diuretics. Symptoms of hyponatremia are usually neuropsychiatric (e.g. restlessness, lethargy, cognitive impairment), and any worsening in psychiatric symptoms in patients with a corresponding risk-profile receiving SSRIs or venlafaxine should give cause to check serum electrolytes. Usually SSRI-induced hyponatremia occurs within approximately 30 days and is reported to improve after withdrawal of the drug. Further controlled studies to confirm the true incidence of hyponatremia due to SSRI or venlafaxine and to define predictors more precisely are needed.
低钠血症定义为血清钠水平低于 135mmol/L，是一种潜在的危及生命的病症，在老年患者和精神科患者中更为常见。近年来，有大量关于 SSRI 和文拉法辛引起的低钠血症的病例报告发表，表明其发病率高于先前的估计。仅有少数研究进行了此类研究，报告的发病率差异很大，从每 1000 人 4.6 例到 25 例不等。目前尚不清楚是否任何一种 SSRI 的低钠血症发病率都高于其他药物。一些数据表明，文拉法辛与低钠血症的相关性可能比 SSRI 更强。危险因素包括年龄、女性、低体重指数、严重躯体疾病、既往低钠血症史以及已知可引起低钠血症的合并用药，特别是噻嗪类利尿剂。低钠血症的症状通常为神经精神症状（如烦躁不安、昏睡、认知障碍），在接受 SSRI 或文拉法辛治疗且具有相应风险特征的患者中，任何精神症状的恶化都应引起注意，需检查血清电解质。通常 SSRI 引起的低钠血症发生在大约 30 天内，停药后会改善。需要进一步进行对照研究以确认 SSRI 或文拉法辛引起的低钠血症的真实发病率，并更准确地确定预测因素。
