Background Terminal agitation is a common symptom in the last days of life which is usually manageable using standard measures. In rare circumstances, it’s necessary to use Phenobarbital. This service evaluation aimed to describe the characteristics of patients requiring Phenobarbital for management of terminal agitation in an inpatient palliative care unit between Nov 2019 and May 2022, with a specific focus on identifying potential risk factors for its use.

Methods Cases were identified by searching the unit’s controlled drug books for the selected period. Clinical notes were reviewed and relevant data entered onto a proforma. Risk factors for terminal distress were summarised numerically and thematically using accepted holistic assessment domains (physical, psychological, social/family and spiritual/existential) as a framework. For comparison, the clinical notes of a control sample (consecutive deaths where phenobarbital was not used from a random month in 2021) were also reviewed.

Results Phenobarbital was used in 21/813 deaths (2.6%), of which 20 sets of notes were reviewed. Mean (SD) age was 53.8 (15.1) in the Phenobarbital group compared to 73.9 (16.4) in the control group. 17/20 Phenobarbital cases (85%) had risk factors across 3 or more holistic domains compared to 4/30 controls (13%). Physical symptoms included refractory pain and breathlessness. Psychological factors included fear of dying or pain, severe anxiety and significant mental health co-morbidities. Spiritual/existential factors included lack of acceptance of prognosis or engagement in advance care planning and being ‘too young to die’. Social factors included complex family dynamics, high levels of anxiety, unrealistic expectations in family members and having younger children.

Conclusions The frequency of Phenobarbital use was consistent with previous reports. Patients requiring it had multiple risk factors for distress in comparison with the control group. Prospective studies are needed to further examine this relationship.