Olanzapine-associated neuroleptic malignant syndrome: Is there an overlap with the serotonin syndrome?

Vassilis P Kontaxakis , Beata J Havaki-kontaxaki , Nikolaos G Christodoulou , Konstantinos G Paplos and George N Christodoulou

Department of Psychiatry, University of Athens, Eginition Hospital, Athens, Greece

author email corresponding author email

Annals of General Hospital Psychiatry 2003, 2:10doi:10.1186/1475-2832-2-10


Published:	29 October 2003

Abstract

Background

The neuroleptic malignant syndrome is a rare but serious condition mainly associated with antipsychotic medication. There are controversies as to whether "classical" forms of neuroleptic malignant syndrome can occur in patients given atypical antipsychotics. The serotonin syndrome is caused by drug-induced excess of intrasynaptic 5-hydroxytryptamine. The possible relationship between neuroleptic malignant syndrome and serotonin syndrome is at present in the focus of scientific interest.

Methods

This retrospective phenomenological study aims to examine the seventeen reported olanzapine – induced neuroleptic malignant syndrome cases under the light of possible overlap between neuroleptic malignant syndrome and serotonin syndrome clinical features.

Results

The serotonin syndrome clinical features most often reported in cases initially diagnosed as neuroleptic malignant syndrome are: fever (82%), mental status changes (82%) and diaphoresis (47%). Three out of the ten classical serotonin syndrome clinical features were concurrently observed in eleven (65%) patients and four clinical features were observed in seven (41%) patients.

Conclusion

The results of this study show that the clinical symptoms of olanzapine-induced neuroleptic malignant syndrome and serotonin syndrome are overlapping suggesting similarities in underlying pathophysiological mechanisms.