title: Clozapine restores water balance in schizophrenic patients with polydipsia-hyponatremia syndrome.
abstract: Hyponatremia/hypoosmolemia causes marked morbidity and prolongs hospital stays in a significant subset of schizophrenic patients. Case reports with methodological limitations suggest clozapine ameliorates this water imbalance. To more conclusively assess this possibility, we completed a 24-week open-label study in 8 male polydipsic hypoosmolemic schizophrenic inpatients. Subjects were treated initially for 6 weeks with a conventional neuroleptic, which was replaced by 300, 600, and 900 (if tolerated) mg/day of clozapine for sequential 6-week periods. On clozapine, mean plasma osmolality rose an average of 15.2 mosm/kg (95% CI: 5.5-25.0). Dosage of 300 mg/day of clozapine was sufficient to normalize plasma osmolality and was generally well tolerated. Clozapine appears to be the first effective pharmacotherapy for severe water imbalance in schizophrenia.
authors.affiliation: Psychiatric Institute, University of Illinois at Chicago, USA.
authors.forename: C M
authors.initials: CM
authors.lastname: Canuso
authors.forename: M B
authors.initials: MB
authors.lastname: Goldman
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D014150:Antipsychotic Agents / Q000627:therapeutic use*; D003024:Clozapine / Q000627:therapeutic use*; D003192:Compulsive Behavior / Q000150:complications / Q000188:drug therapy*; D004305:Dose-Response Relationship, Drug; D004326:Drinking / Q000187:drug effects*; D006801:Humans; D007010:Hyponatremia / Q000209:etiology* / Q000517:prevention & control; D008297:Male; D008875:Middle Aged; D009994:Osmolar Concentration; D011446:Prospective Studies; D012559:Schizophrenia / Q000097:blood / Q000150:complications / Q000188:drug therapy*; D016896:Treatment Outcome; D014869:Water Intoxication / Q000517:prevention & control