(913) Evaluation of Phenobarbital Dosing in Hospitalized Patients With Alcohol Withdrawal Syndrome

Introduction: Alcohol remains the fourth-leading preventable cause of death in the United States. Phenobarbital (PHB) has been associated with a reduction in AWS symptoms, ICU and hospital length of stay (LOS), and rates of mechanical ventilation in hospitalized patients with AWS. The objectives of this study are to assess front-loaded PHB dosing strategies for the management of AWS and determine the incidence and risk factors for PHB-resistant alcohol withdrawal.

Methods: This single-center, retrospective cohort study included all adults admitted to Duke University Hospital with AWS who received PHB as part of an institution-specific treatment protocol between November 16, 2021 - September 1, 2022. The primary outcome was incidence of AWS resistant to initial PHB loading dose (standard-dose, 10 mg/kg vs. low-dose, 6 mg/kg). Secondary outcomes included risk factors associated with PHB-resistant alcohol withdrawal, incidence of PHB-related adverse effects (ADEs), and PHB dosing strategies in the setting of PHB-resistant alcohol withdrawal.

Results: A total of 176 patients were included in the study. There was no difference in the incidence of PHB-resistant alcohol withdrawal based on initial PHB loading dose [low-dose load, 21 (18.3%) vs. standard-dose load, 12 (19.7%), p=0.819]. Among the 33 patients who developed PHB-resistant withdrawal, the median cumulative re-loading dose was 5.9 mg/kg (IQR 3.5 – 7.8 mg/kg). There were no differences in observed PHB-related ADEs between the groups. Hospital LOS was longer in patients who received the low-dose load [6 days (IQR 3.6 – 10.5 days) vs. 4 days (IQR 3 - 6.9 days), p=0.008]. In the adjusted risk analysis, the only variable significantly associated with the occurrence of PHB-resistant withdrawal was total benzodiazepine dose received (mg) in the 24 hours prior to initial PHB load [adjusted OR 1.79 (95% CI 1.24, 2.60)].

Conclusions: PHB-resistant withdrawal occurred in 33 (18.8%) of patients with the median dose during hospitalization being approximately 20 mg/kg. There were no differences in the incidence of PHB-related ADEs based on initial PHB loading dose.