In this episode, I’ll discuss whether patients taking beta-blockers require increased doses of epinephrine for anaphylaxis.
Animal data suggests that patients taking beta-blockers have more severe anaphylaxis, possibly by decreasing the threshold for mast cell activation.
Because beta-blockers interfere with the same receptors epinephrine needs to activate to effectively treat anaphylaxis, there is concern that patients with anaphylaxis who regularly take beta-blockers may need higher doses of epinephrine or an alternative treatment approach that is not dependent on beta-receptor availability, such as glucagon.
To determine whether the risk of requiring more than 1 dose of epinephrine for anaphylaxis treatment is increased among ED patients taking beta-blockers, a group of researchers conducted a retrospective, single-center observational study of ED patients with anaphylaxis. Nearly 800 patients were analyzed, and the study was powered to detect a 10% or greater difference in the need for repeat epinephrine administration between patients taking beta-blockers and those not taking them.
In the entire cohort, 11% of the patients with anaphylaxis were taking a beta-blocker. A small number of patients in the cohort required more than 1 dose of epinephrine (8%). Of the patients taking a beta-blocker, 13% required more than one dose; however, even though this was numerically higher than the overall cohort, the difference was not statistically significant, with a p value of 0.56.
When the authors applied multivariate analysis, the association of beta-blocker use with the need for more than 1 dose of epinephrine remained statistically nonsignificant after adjusting for age, sex, precipitating allergen, COPD, and cardiovascular disease.
Therefore, despite having a physiologic rationale, the authors concluded that:
…our results demonstrate that after controlling for COPD and cardiovascular comorbid conditions, age, and sex, the use of b-blockers was not associated with at least a 10% increase in the need for more than 1 dose of epinephrine. Although it is possible that the risk of repeat epinephrine is smaller than 10%, the clinical significance of this is uncertain and may not outweigh the benefits of b-blockers for other conditions.
The practical application of this data is that, even for patients taking beta-blockers, epinephrine at the standard dose is the first-line treatment for anaphylaxis. Additional doses of epinephrine should be given based on clinical need and not based simply on a history of beta-blocker use.
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.
If you like this post, check out my book – A Pharmacist’s Guide to Inpatient Medical Emergencies: How to respond to code blue, rapid response calls, and other medical emergencies.
Leave a Reply