Phenobarbital versus benzodiazepines in alcohol withdrawal syndrome

Impact of a Divided Phenobarbital Load and Taper Compared With Lorazepam Symptom Triggered Therapy in Hospitalized Patients

BACKGROUND

Benzodiazepines are the preferred treatment for alcohol withdrawal. Phenobarbital is an alternative in the setting of prescriber expertise or benzodiazepine contraindication.

OBJECTIVE

To evaluate the efficacy and safety of a phenobarbital dosing strategy aimed at treating a spectrum of alcohol withdrawal symptoms across various patient populations.

METHODS

Retrospective review of patients admitted with concerns of alcohol withdrawal between May 2018 and November 2022. Patients were separated into a before-after cohort of lorazepam or phenobarbital. The primary outcome was hospital length of stay (LOS). Secondary outcomes were intensive care unit (ICU) LOS, escalation of respiratory support, increased level of care (LOC), and incidence of delirium tremens and/or seizures.

RESULTS

Two hundred and seventy-seven patients received lorazepam and 198 received phenobarbital. Hospital LOS was longer in the phenobarbital cohort compared with the lorazepam cohort (6.9 vs 9.3 days). There was no difference in ICU LOS. Level of care increases were fewer in the phenobarbital cohort (4 events vs 19 events). There were higher rates of non-invasive respiratory interventions in the lorazepam cohort and higher rates of mechanical ventilation in the phenobarbital cohort. Utilization of phenobarbital was attributed to a reduction in delirium tremens and seizures.

CONCLUSION AND RELEVANCE

This study is novel because of the broad application of a phenobarbital order set across multiple levels of care and patient admission diagnoses. A risk targeted split load intravenous phenobarbital order set can safely be administered to patients with fewer escalations of care, seizures, delirium tremens, and respiratory care escalation.

Evaluation of the Use of Phenobarbital and Benzodiazepines in the Management of Alcohol Withdrawal Syndrome in Patients Requiring Neurological/Neurosurgical Critical Care: A Propensity-Matched Analysis

Objective There is growing interest in the use of phenobarbital for alcohol withdrawal syndrome in critically ill patients, though experience in neurologically injured patients is limited. The purpose of this study was to compare the safety and effectiveness of phenobarbital-containing alcohol withdrawal regimens versus benzodiazepine monotherapy in the neurocritical care unit. Methods We conducted a retrospective cohort study of adult patients admitted to the neurocritical care unit from January 2014 through November 2021 who received pharmacologic treatment for alcohol withdrawal. Treatment groups were defined as benzodiazepine monotherapy versus phenobarbital alone or in combination with benzodiazepines. The primary outcome was the percentage of patients requiring intubation after receiving alcohol withdrawal treatment. Secondary outcomes included all-cause, in-hospital mortality, intensive care unit length of stay, discharge disposition, change in Glasgow Coma Scale (GCS) score, and the use of adjunctive agents. Results We analyzed data from 156 patients, with 77 (49%) in the benzodiazepine group and 79 (51%) in the phenobarbital combination group. The groups were well-balanced for baseline characteristics, though more males (67, 85%) were in the phenobarbital group. Only three (1.9%) patients received phenobarbital monotherapy, and the rest (153, 98.1%) received combination therapy. The percentage of patients requiring mechanical ventilation was significantly higher in the phenobarbital combination group compared to benzodiazepine monotherapy (39% (n=31) versus 13% (n=10); OR: 4.33, 95% CI: 1.94-9.66; p<0.001). The use of adjunctive propofol and dexmedetomidine was higher in the phenobarbital group (propofol 35% (n= 28) versus 9% (n=7) and dexmedetomidine 30% (n=24) versus 5% (n=4), respectively). Patients in the phenobarbital group also had lower GCS scores and higher Clinical Institute Withdrawal Assessment of Alcohol (CIWA-Ar) scores during their intensive care unit admission, possibly suggesting more severe alcohol withdrawal. There was no difference in intensive care unit length of stay, all-cause, in-hospital mortality, discharge disposition, or therapeutic adjuncts. Conclusions Combination therapy of phenobarbital plus benzodiazepines was associated with higher odds of requiring mechanical ventilation. Few patients received phenobarbital monotherapy. Additional studies are needed to better compare the effects of phenobarbital monotherapy versus benzodiazepines in neurocritical patients.

GABAergic mechanisms in alcohol dependence

The target of alcohol's effect on the central nervous system has been sought for more than 50 years in the brain's GABA system. The behavioral and emotional effects of alcohol in humans and rodents are very similar to those of barbiturates and benzodiazepines, and GABAA receptors have been shown to be one of the sites of alcohol action. The mechanisms of GABAergic inhibition have been a hotspot of research but have turned out to be complex and controversial. Genetics support the involvement of some GABAA receptor subunits in the development of alcohol dependence and in alcohol use disorders (AUD). Since the effect of alcohol on the GABAA system resembles that of a GABAergic positive modulator, it may be possible to develop GABAergic drug treatments that could substitute for alcohol. The adaptation mechanisms of the GABA system and the plasticity of the brain are a big challenge for drug development: the drugs that act on GABAA receptors developed so far also may cause adaptation and development of additional addiction. Human polymorphisms should be studied further to get insight about how they affect receptor function, expression or other factors to make reasonable predictions/hypotheses about what non-addictive interventions would help in alcohol dependence and AUD.

Evaluation of Clinical Outcomes Associated With Phenobarbital With Taper Compared to No Taper for the Management of Alcohol Withdrawal Syndrome

BACKGROUND

Phenobarbital (PHB) has been shown to be an effective treatment of alcohol withdrawal syndrome (AWS), with multiple dosing strategies used (e.g., single-dose and symptom-triggered). Studies have often used tapered doses, typically following a front-loaded dose, despite PHB's long half-life which should lead to an ability to auto-taper.

OBJECTIVE

The purpose of this study was to compare clinical outcomes associated with two PHB dosing strategies (taper [T], no taper [NT]) for AWS.

METHODS

This retrospective cohort study compared adult patients admitted to the ICU from October 2017 to May 2019 who received an initial loading dose of PHB for AWS. The use of PHB was at the discretion of the clinician per our institutional guidelines. Prior to November 2018, patients were prescribed a PHB taper, while after this period, the taper was no longer recommended. The primary outcome was the proportion of patients requiring rescue PHB or adjunctive medications for AWS. Secondary outcomes included number of adjunctive agents used, prevalence of severe manifestations of AWS, ICU and hospital lengths of stay, and incidence of potentially significant drug interactions.

RESULTS

A total of 172 patients were included (T: n = 81, NT: n = 91). Baseline characteristics were similar between groups, including history of severe AWS and cumulative benzodiazepine dose pre-PHB. There was no difference in the primary outcome between groups (T: 70.4% vs NT: 59.3%, P = 0.152). The median number of adjunctive agents per patient, severe manifestations, and ICU and hospital length of stay did not differ between groups. Twenty-five patients (14.5%) had potentially significant drug interactions.

CONCLUSION AND RELEVANCE

The use of a PHB loading dose without a taper may be comparable to a taper strategy on clinical outcomes. Prospective studies are needed to further delineate the optimal dose of PHB for AWS.