Abstract
Olanzapine is a second-generation atypical antipsychotic agent approved for the treatment of psychotic disorders and mania. The effects of olanzapine intoxication include central nervous system depression, hyperthermia, myosis, tachycardia, and orthostatic hypotension. Heretofore, only one case has been reported to develop polyuria after olanzapine overdose (560 mg). We describe a case that developed diabetes insipidus following massive olanzapine ingestion and returned to normal after desmopressin treatment.
INTRODUCTION
Olanzapine is a second-generation antipsychotic. The effects of olanzapine intoxication include central nervous system depression, hyperthermia, myosis, tachycardia, and orthostatic hypotension.Citation1 Heretofore, only one case has been reported to develop polyuria after olanzapine overdose.Citation2 We report a case that developed diabetes insipidus after massive olanzapine ingestion.
CASE REPORT
A 29-year-old male patient had been taking olanzapine 10 mg twice daily since he had been diagnosed as schizophrenia 4 years ago. He was admitted to our emergency service after he had ingested 56 tablets (560 mg) of olanzapine for suicide. He was reported to take no drugs except olanzapine. He was unconscious with normal vital signs except sinus tachycardia. He was referred to the intensive care unit. Oral intake was stopped and intravenous isotonic solution (100 cc/h) was started. The patient’s input–output balance was monitored. Within the first day of admission, he had a maximum urinary output of 310 cc/h. The patient’s urinary output was 7190 cc within the first 24 h. Urine density was lower than 1005 and serum osmolality was 291 mosmol/kg H2O. Blood glucose and serum sodium was normal. Blood concentration of antidiuretic hormone (ADH) was 5.3 pgmL/mL (normal range = 0.0–8.0), and thyroid stimulating hormone level was 2.3 μUmL/mL (normal range = 0.2–4.2), with normal free triiodothyronine and thyroxin values. Mr. A regained consciousness on the second day of hospitalization and was started on desmopressin nasal spray (40 μg/4 h) which was continued for 3 days. The diagnosis of central diabetes insipidus was confirmed by a rise in urine osmolality after desmopressin. On the third day of hospitalization, his urine output was within the normal range and he was discharged from the intensive care unit on day 5. The patient has been followed for 2 months with no evidence of recurrence of polyuria.
DISCUSSION
Polyuria and hypo-osmolar urine with normal serum osmolality were supportive for the diagnosis of diabetes insipidus in our patient. Dramatic improvement in urine output after first dose of desmopressin suggests diabetes insipidus of central origin.
Although olanzapine is generally a safe antipsychotic, it may cause hyperglycemia, diabetes, and weight gain.Citation3 Lithium treatment related diabetes insipidus and polyuria has been reported in patients with schizophrenia. However, these are nephrogenic diabetes insipidus. Additionally, clozapine, which is chemically associated with olanzapine, may also cause diabetes insipidus of renal origin.Citation4 Our case is similar to that described by Etienne et al.Citation2 in which polyuria was seen after ingestion of 75 mg olanzapine. Our case differs with higher dose exposure. Furthermore, our patient was unconscious at admission and his maximum urinary output was higher (5400 cc vs. 7190 cc). The low normal level of ADH in this patient probably represents early or partial central diabetes insipidus. As a limitation of our case report, it can be said that detecting the blood level of olanzapine after high-dose ingestion and its relation to diabetes insipidus might be more explanatory.
Transient diabetes insipidus may occur as a result of olanzapine intoxication and clinicians should consider olanzapine intoxication in patients with diabetes insipidus in the presence of olanzapine treatment.
Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.
References
- Morgan M, Hackett LP, Isbister GK. Olanzapine overdose: A series of analytically confirmed cases. Int Clin Psychopharmacol. 2007;22:183–186.
- Etienne L, Wittebole X, Liolios A, Hantson P. Polyuria after olanzapine overdose. Am J Psychiatry. 2004;161(6):1130.
- Leslie DL, Rosenheck RA. Incidence of newly diagnosed diabetes attributable to atypical antipsychotic medications. Am J Psychiatry. 2004;161(9):1709–1711.
- Bendz H, Aurell M. Drug-induced diabetes insipidus: Incidence, prevention and management. Drug Saf. 1999;21:449–456.