Use of olanzapine to treat agitation in traumatic brain injury: study protocol for a randomised controlled trial

Agitation is common in the early stages of recovery from traumatic brain injury (TBI), when patients are in post-traumatic amnesia (PTA). Agitation is associated with risk of harm to patients and caregivers. Recent guidelines recommend that agitation during PTA is managed using environmental modifications. Agitation is also frequently treated pharmacologically, with the use of atypical antipsychotics such as olanzapine among the most common. This is despite a lack of well-designed studies to support the use of antipsychotics within this context. This study will be a double-blind, placebo-controlled randomised controlled trial. We will examine the efficacy, safety, cost-effectiveness and outcomes associated with the use of olanzapine for reducing agitation in patients in PTA following TBI over and above recommended environmental management.

Fifty-eight TBI rehabilitation inpatients who are in PTA and are agitated will receive olanzapine or placebo for the duration of PTA. All participants will additionally receive optimal environmental management for agitation. Measures of agitation, PTA and health will be undertaken at baseline. Treatment administration will begin at a dose of 5 mg daily and may be escalated to a maximum dose of 20 mg per day. Throughout the treatment period, agitation and PTA will be measured daily, and adverse events monitored weekly. Efficacy will be assessed by treatment group comparison of average Agitated Behaviour Scale scores during PTA. Participants will cease treatment upon emergence from PTA. Agitation levels will continue to be monitored for a further 2 weeks, post-treatment measures of health will be undertaken and cognitive and functional status will be assessed. Level of agitation and functional health will be assessed at hospital discharge. At 3 months post-discharge, functional outcomes and health service utilisation will be measured.

This trial will provide crucial evidence to inform the management of agitation in patients in PTA following TBI. It will provide guidance as to whether olanzapine reduces agitation over and above recommended environmental management or conversely whether it increases or prolongs agitation and PTA, increases length of inpatient hospitalisation and impacts longer term cognitive and functional outcomes. It will also speak to the safety and cost-effectiveness of olanzapine use in this population.

ANZCTR ACTRN12619000284167 . Registered on 25 February 2019.