The study was terminated prematurely due to difficulties in patient recruitment and associated potential for selection bias.

The purpose of this study is to determine whether oral olanzapine is safer (fewer adverse events) and more effective (shorter time to sedation) than conventional haloperidol or diazepam when used in the management of acute agitation in the emergency.

1. Investigate oral use of sedating drugs within a predominantly Chinese population, to address this void in international literature impacting the management of acute agitation.
2. The multi-centre Randomised Clinical Trial will determine the safety and efficacy of oral olanzapine, in comparison with conventional medicines (haloperidol or diazepam) in a three-arm comparison for the sedation of acutely agitated patients in AEDs. Specifically, we aim to determine if administration of oral olanzapine (a)is more effective than sedation with oral haloperidol or oral diazepam alone; (b)is safer than sedation with comparison arms; (c)decreases the amount of subsequent redosing or alternative drugs required; (d)is more favourable than the haloperidol and diazepam arms with respect to safety, efficacy and adverse events.

Investigate potential variables leading to AED attendance and/or admission requiring oral sedation. These may include patient demographic and regular medications and adherence.

Inclusion Criteria:

• Accident & Emergency Department patients
• Requiring oral drug sedation (as determined by an emergency clinician) will be enrolled.

Exclusion Criteria:

• known hypersensitivity or contraindication to the study drugs
• reversible aetiology for agitation (e.g. hypotension, hypoxia, hypoglycaemia)
• known pregnancy
• acute alcohol withdrawal
• refusal to take oral medication
• patients from correctional facilities