In this episode, I’ll discuss hemodynamic changes after using a dexmedetomidine loading dose in ED patients.
Dexmedetomidine has many properties that make it an ideal sedative, such as not causing respiratory depression, having an analgesic sparing effect, and having a reduced risk of delirium. One drawback, however, is the relatively slow onset of action, with it taking about 30 minutes after starting a dexmedetomidine infusion before sedation is achieved.
To achieve a faster onset of action, the labeling for dexmedetomidine includes instructions for giving a loading dose of 1 mcg/kg IV over 10 minutes. Unfortunately, this loading dose is often associated with increased rates of hemodynamic adverse events such as hypotension and bradycardia.
Because having a hemodynamic adverse event to dexmedetomidine often means needing to use another sedative with less desirable long-term effects, many clinicians have abandoned using the loading dose altogether and accept that bolus doses of an opioid and/or benzodiazepine might be needed to bridge the time from when a dexmedetomidine infusion starts and the onset of sedative effects begins.
Since the majority of the clinical experience with using dexmedetomidine has been in the intensive care unit, a group of authors published a research letter in Academic Emergency Medicine looking at the hemodynamic effects of a dexmedetomidine loading dose in ED patients. The authors retrospectively analyzed data from 73 patients who received a dexmedetomidine loading dose in their ED.
When measured at 31 to 40 minutes after the loading dose was given, the median decrease in heart rate was 17 bpm, and the median reduction in systolic blood pressure was 20 mmHg. 11 of the 73 patients had a significant hemodynamic event, with two developing bradycardia, five developing hypotension, and four developing both. Of the patients who developed hypotension or bradycardia, 5 of 11 had a heart rate reduction of greater than 20 bpm, and 7 of 11 patients had a BP reduction greater than 40 mmHg.
Even with its limitations of being a single-center retrospective study, this data confirms the significant 15% incidence of bradycardia and hypotension in ED patients from a dexmedetomidine loading dose. I think clinicians should consider using no loading dose and, if needed, use another sedative for the 30 or so minutes it will take for dexmedetomidine to work.
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.
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