Objectives Identify the indication, route of administration and dose for phenobarbital continuous subcutaneous infusion (CSCI) in palliative sedation therapy (PST).

Assess the dosing and continuation of midazolam and levomepromazine in conjunction with phenobarbital.

Methods This clinical audit examined inpatient phenobarbital CSCI use for PST from January 2021 to April 2024. Data were retrospectively extracted from electronic medical records (n=23).

Results The most common indication for phenobarbital CSCI was agitation, followed by sedation for non-invasive ventilation withdrawal. Phenobarbital was administered subcutaneously in all cases without adverse systemic or site reactions.

The most common loading dose was 200 mg (50–200 mg), and the most common initiating CSCI dose was 800 mg/24 hours (400–1200 mg/24 hours). The maximum dose was 1800 mg/24 hours. The average time to death following start of phenobarbital was 52 hours (4–123 hours). Most patients (n=22) were described as comfortable at death.

Before starting phenobarbital CSCI, all patients were on midazolam CSCI (mean dose 50 mg), which was continued in 14 patients. Seventeen patients received levomepromazine CSCI (mean dose 137 mg), which was continued in 12 patients.

Conclusion Phenobarbital appears to be an effective medication for PST. However, inconsistencies in dosing, concurrent sedative medication use and standardised protocols highlight areas for improvement in clinical guidelines.