title: Hyponatraemia during psychopharmacological treatment: results of a drug surveillance programme.
abstract: Hyponatraemia (HN) can be a life-threatening medical condition which may lead to severe neurological and psychiatric symptoms. The AMSP (Arzneimittelsicherheit in der Psychiatrie) is a multicentre drug surveillance programme that assesses severe or new adverse drug reactions during psychopharmacological treatment in psychiatric inpatients. We report on a total of 263 864 psychiatric inpatients monitored from 1993 to 2007 in 80 psychiatric hospitals in Germany, Switzerland and Austria. During this period plasma sodium levels below 130 mmol/l (severe HN according to AMSP) were reported in 93 patients (relative frequency 0.04%). On average, the plasma sodium levels of all cases were 119.7 mmol/l (±5.8 s.d.); median 121 mmol/l (range 104-129 mmol/l). Patients who showed no clinical signs (n=65, 70%) had a mean sodium level of 121.3 mmol/l (±5.0 s.d.); median 122 mmol/l (range 114-129 mmol/l). By contrast, patients with clinical symptoms (n=28, 30%) had a mean sodium level of 116.0 mmol/l (±6.0 s.d.); median 117 mmol/l (range 104-125 mmol/l). HN was mainly observed during treatment with selective serotonin reuptake inhibitors (SSRIs) (0.06%), Serotonin noradrenaline reuptake inhibitors (SNRIs) (0.08%), carbamazepine (0.10%) and oxcarbazepine (1.29%); the highest rate was found for oxcarbazepine. Antipsychotics, mirtazapine and tricyclic antidepressants were only rarely involved in HN (0.003-0.005%). Combinations of several drugs known to induce HN significantly increased the risk of HN, e.g. more than 10-fold for SSRI+diuretics+ACE inhibitors (0.37%) vs. SSRI given alone (0.02%). This is clinically relevant because such combinations, e.g. SSRI+diuretics may occur especially in elderly patients, who are in general at higher risk of developing HN.
authors.affiliation: Department of Psychiatry, Medical University of Graz, Graz, Austria. martin.letmaier@klinikum-graz.at
authors.forename: Martin
authors.initials: M
authors.lastname: Letmaier
authors.forename: Annamaria
authors.initials: A
authors.lastname: Painold
authors.forename: Anna Katharina
authors.initials: AK
authors.lastname: Holl
authors.forename: Hartmut
authors.initials: H
authors.lastname: Vergin
authors.forename: Rolf
authors.initials: R
authors.lastname: Engel
authors.forename: Anastasios
authors.initials: A
authors.lastname: Konstantinidis
authors.forename: Siegfried
authors.initials: S
authors.lastname: Kasper
authors.forename: Renate
authors.initials: R
authors.lastname: Grohmann
mesh_terms: D016907:Adverse Drug Reaction Reporting Systems; D000368:Aged; D014150:Antipsychotic Agents / Q000009:adverse effects* / Q000493:pharmacokinetics; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D007010:Hyponatremia / Q000139:chemically induced* / Q000453:epidemiology; D015994:Incidence; D007391:International Cooperation; D008297:Male; D001523:Mental Disorders / Q000188:drug therapy / Q000453:epidemiology; D008875:Middle Aged; D011358:Product Surveillance, Postmarketing; D012189:Retrospective Studies; D012307:Risk Factors; D012964:Sodium / Q000097:blood
chemical_list: D014150:Antipsychotic Agents; D012964:Sodium