.jpg "Ashley Asbell, PharmD photo")
Ashley Asbell, PharmD
PGY2 Critical Care Pharmacy Resident
UVA Health
Charlottesville, VA
Disclosure information not submitted.
Emily Burns, PharmD, BCPS
Cardiovascular Clinical Pharmacist
UVA Health, United States
Disclosure information not submitted.
Cameron Lee, PharmD
Investigational Drug Services Pharmacist - Oncology
UVA Health, United States
Disclosure information not submitted.
Mary Roth, PharmD, BCPS, BCCP
Cardiovascular Clinical Pharmacist
UVA Health, United States
Disclosure information not submitted.
Title: Drug interaction mitigation following implementation of a phenobarbital alcohol withdrawal protocol
Introduction: Phenobarbital (PHB) has a long history of use in the prevention of complicated alcohol withdrawal syndrome (AWS) in high-risk, hospitalized patients. Over the past several decades, its use has declined due to concerns surrounding its strong cytochrome P450 3A4 induction. Recently however, interest in PHB for complicated alcohol withdrawal has reemerged owing to its long half-life. In 2019, UVA Health updated its AWS guideline to prefer PHB in high-risk patients. In doing so, specific drug-drug interactions (DDIs) with direct oral anticoagulants (DOACs) were highlighted. Here, we describe strategies UVA Health has implemented to mitigate these DDIs.
Methods: Following a retrospective chart review of patients admitted between April 2019 and August 2020, several strategies were formulated to reduce the DDI rate. One focus area was the prolonged period of enzyme induction for upwards of two weeks following drug clearance. To address this, the DDI alert window for PHB was extended to 30 days after the last administered dose: 16 days to account for PHB’s half-life, and 14 additional days to account for the resolution of enzyme induction. Additionally, language was added to the AWS order set to steer providers away from PHB if the patient was likely to need a DOAC during admission. Following implementation in February 2021, two reviews were performed: one of alert data for any PHB DDI that required acknowledgement, and the second of patients with PHB and a DOAC ordered in the same encounter. Each compared patients 5 months before and after implementation.
Results: PHB-DOAC DDI alerts constituted 16% of total PHB DDI alerts. PHB-related alerts nearly doubled following DDI window extension (242 vs. 417). Six patients in each group had both PHB and an interacting agent ordered and administered during the same encounter, however the rate at which they received at least one dose of both agents decreased (75% vs. 54%) while the rate of intervention and order discontinuation prior to administration increased (38% vs. 64%).
Conclusions: Strategies such as PHB DDI alert window extension and the addition of language within the AWS order set appeared to increase the rate at which interacting orders were intervened on and discontinued prior to administration.