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Case Series Profile of Olanzapine Post-Injection Delitrium/Sedation Syndrome
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  • Jason Seebaluck,
  • Michael Downes,
  • Jared A. Brown,
  • Keith Harris,
  • Katherine Isoardi,
  • Betty Chan
Jason Seebaluck
Prince of Wales Hospital and Community Health Services

Corresponding Author:jasonseebaluck@gmail.com

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Michael Downes
Calvary Mater Newcastle
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Jared A. Brown
Children's Hospital at Westmead
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Keith Harris
Princess Alexandra Hospital Health Service District
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Katherine Isoardi
Princess Alexandra Hospital
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Betty Chan
University of New South Wales
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Olanzapine pamoate is an intramuscular depot injection for the treatment of schizophrenia. Approximately 1.4% of patients develop a serious adverse event called Post Injection Delirium/Sedation Syndrome (PDSS); characterised by drowsiness, anticholinergic and extrapyramidal symptoms. The objective is to investigate olanzapine PDSS presentations including clinical features and treatment approach. This is a retrospective review of olanzapine PDSS patients from three toxicology units and the NSW Poisons Information between 2017 and 2022. Adult patients were included if they had intramuscular olanzapine then developed PDSS criteria. Clinical symptoms, treatment, timing and length of symptoms were extracted into a preformatted Excel database. There were 18 patients included in the series, with a median age of 49 years (IQR: 38-58) and male predominance (89%). Median onset time post injection was 30 minutes (IQR: 11-38). PDSS symptoms predominate with drowsiness, confusion and dysarthria. Median length of symptoms was 24 hours (IQR: 20-54). Most common treatment included supportive care without any pharmacological intervention (n=10), benzodiazepine (n=4) and benztropine (n=3). In one case, bromocriptine and physostigmine followed by oral rivastigmine were given to manage anti-dopaminergic and anti-cholinergic symptoms respectively. This proposed treatment combination could alleviate some of the symptoms. In conclusion, this case series supports the characterisation of PDSS symptomology predominantly being anti-cholinergic with similar onset (<1 hour) and duration (<72hours). A combination of bromocriptine and physostigmine followed by rivastigmine is proposed to manage PDSS if patients develop severe dopamine blockade or anti-cholinergic delirium.
04 Sep 2022Submitted to British Journal of Clinical Pharmacology
05 Sep 2022Submission Checks Completed
05 Sep 2022Assigned to Editor
12 Sep 2022Reviewer(s) Assigned
26 Sep 2022Review(s) Completed, Editorial Evaluation Pending
10 Oct 2022Editorial Decision: Revise Minor
21 Oct 20221st Revision Received
22 Oct 2022Submission Checks Completed
22 Oct 2022Assigned to Editor
22 Oct 2022Review(s) Completed, Editorial Evaluation Pending
31 Oct 2022Editorial Decision: Accept