In this episode, I’ll discuss respiratory depression from phenobarbital when used for alcohol withdrawal syndrome.
Phenobarbital is increasing in popularity among clinicians for use in the treatment of alcohol withdrawal syndrome. Even though there is less data available on patient outcomes using phenobarbital over benzodiazepines for severe alcohol withdrawal, some reports suggest that rates of complications and length of hospital stay are lower with phenobarbital.
Advocates of phenobarbital use for severe alcohol withdrawal often perceive the risk of respiratory depression from phenobarbital as an argument against its use, and a group of researchers published in the journal Critical Care a description of their experience with phenobarbital and rates of respiratory depression.
The authors had previously implemented a protocol that included phenobarbital for selected cases of alcohol withdrawal using a phenobarbital load, defined as a dose of at least 7 mg/kg. They identified 57 patients who received phenobarbital under this protocol and looked at the subsequent 24 hours post-phenobarbital loading dose for any increase in respiratory support, from new oxygen supplementation to intubation. Of these 57 patients, only 6 experienced an escalation of respiratory support within 24 hours of phenobarbital loading. All 6 of these patients required intubation. However, 5 of the 6 patients were not intubated as a consequence of respiratory depression from phenobarbital. Three intubations were for persistent withdrawal symptoms, 1 for airway protection due to seizure, and 1 for GI bleeding. The one patient that appeared to experience a respiratory event related to phenobarbital had also received levetiracetam and benzodiazepines in the hours prior. After this patient received the phenobarbital load, they experienced worsening hypoxia and hypercapnia, which necessitated intubation.
The authors conclude that the risk of respiratory depression after a phenobarbital loading dose for severe alcohol withdrawal is low, and they advocate that:
Expanding the use of phenobarbital loading to general wards, with careful attention to patient selection, could help streamline care, conserve ICU resources, and lower hospital costs. Further prospective evaluations will be important, but our findings provide reassurance that with appropriate safeguards, phenobarbital loading need not be restricted to the ICU.
My opinion is that this analysis completely misses the point. The one patient who seemed to need intubation as a result of receiving phenobarbital had also received benzodiazepines, and it is this type of patient who is at the highest risk of a bad outcome. If a clinician started care in one setting such as the ED with benzodiazepines, and the clinician on a general medical unit decides to use phenobarbital in the same patient, this patient is now at an elevated risk of respiratory depression. If this risk is not identified and the patient’s respiratory status is not monitored appropriately, the result could be catastrophic with respiratory depression occurring but detection being delayed.
This small study doesn’t provide me reassurance that the risk of respiratory depression from phenobarbital is low; rather, it highlights the importance of coordination of care between clinicians in the ED, ICU, and general medical units. If phenobarbital is to be used for alcohol withdrawal, that is fine, but it should be part of an established protocol that all clinicians are aware of, and if benzodiazepines are given to the same patient, appropriate monitoring of respiratory status should be implemented.
The article in this episode is a selection from my Hospital Pharmacy Academy’s weekly literature digest. Have you ever felt like your physician colleagues are one step ahead of you with new literature developments? Every week, Academy members are provided a summary curated and explained by me of the top hospital pharmacy-related articles published that week from over 20 major journals and sources to save you time and keep you up to date with the literature. To get immediate access, go to pharmacyjoe.com/academy.
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