Importance of Boluses with Rate Changes for Opioid & Benzodiazepine Infusions

Today’s pearl provides some advice on how to properly increase sedative rates for intubated patients

Why do boluses matter?

As we manage more critically-ill, mechanically ventilated patients in the ED, there is an important pharmacokinetic principle that bears mentioning: When increasing the rate on an opioid or benzodiazepine infusion, it MUST be simultaneously paired with a bolus.

Example: Patient receiving fentanyl 50 mcg/hr. If we simply increase the rate to 100 mcg/hr, it will take a full hour to receive the additional 50 mcg (and several hrs to reach a new steady-state). This will not help us right now, which is why we need the additional bolus. The bolus is generally 25-50% of the new rate. In this example, 25-50 mcg would be appropriate.

This can be accomplished in two ways in your electronic medical record (i.e., Epic):

1. Choose the bolus from infusion option when ordering which allows nurses to document the additional dose(s)


2. Add a separate prn order for the boluses

Stay safe.




Author: Bryan D. Hayes, PharmD

Attending Pharmacist, Emergency Medicine and Toxicology, Massachusetts General Hospital; Assistant Professor of EM, Harvard Medical School

4 thoughts on “Importance of Boluses with Rate Changes for Opioid & Benzodiazepine Infusions”

  1. Curious as to why this only applies to benzos or opioids. We recently had the option to bolus propofol removed from our pump library but are requesting it be added back based on this same concept.

    Thanks for the post!


    1. Propofol does not need to be bolused with each rate change because its kinetics are very different from opioids and benzodiazepines. The half life is short and so it reaches steady state more quickly. That being said, there are times when propofol boluses are needed so it should still be included in your pump.


  2. Bryan – Which other ED critical care meds have pharmacokinetics that necessitate a bolus with each drip increase. Dexmedetomidine? Esmolol?


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