Transitioning from Norepinephrine 15 mcg/min to Epinephrine
Start epinephrine at 2-5 mcg/min while simultaneously decreasing norepinephrine by 25-50% of the current dose, then titrate epinephrine up every 5-15 minutes while weaning norepinephrine down proportionally until you've fully transitioned to epinephrine alone, targeting a MAP ≥65 mmHg throughout the transition. 1, 2
Initial Transition Strategy
Begin the transition by starting epinephrine at a low dose (2-5 mcg/min or 0.03-0.07 mcg/kg/min for a 70 kg patient) while reducing norepinephrine from 15 mcg/min to approximately 7-10 mcg/min. 1, 2 This overlapping approach prevents precipitous drops in blood pressure during the changeover.
Step-by-Step Titration Protocol
Monitor blood pressure every 5-15 minutes during the entire transition process to ensure hemodynamic stability and avoid dangerous hypotension 1
After starting epinephrine and achieving stable hemodynamics for 10-15 minutes, continue decreasing norepinephrine by 25% increments every 30 minutes while simultaneously increasing epinephrine by 2-3 mcg/min increments 2
Target MAP should remain ≥65 mmHg throughout the transition, though patients with chronic hypertension may require higher targets 1, 2
Complete the transition over 1-2 hours rather than abruptly switching, as this allows time to assess epinephrine's hemodynamic effects and adjust accordingly 1
Critical Monitoring Parameters
Watch for tachycardia and arrhythmias closely during epinephrine titration, as epinephrine has more potent beta-adrenergic effects than norepinephrine and can cause significant heart rate elevation and new arrhythmias 3. In one comparative study, epinephrine was associated with new arrhythmias in 20% of patients, whereas the norepinephrine group had none 3.
Metabolic Considerations
Monitor lactate levels closely during and after the transition, as epinephrine is associated with transient lactic acidosis even when hemodynamics improve 3
Epinephrine infusion increased lactate levels significantly at 6 hours compared to baseline, while norepinephrine decreased lactate in a randomized trial of cardiogenic shock patients 3
This lactate elevation with epinephrine does not necessarily indicate worsening tissue perfusion but rather reflects beta-2 mediated aerobic glycolysis 3
Dosing Equivalence Considerations
There is no direct 1:1 dose equivalence between norepinephrine and epinephrine, as they have different receptor profiles and hemodynamic effects 1, 2. Norepinephrine at 15 mcg/min is a moderate-to-high dose, so expect to need epinephrine in the range of 5-15 mcg/min (0.07-0.2 mcg/kg/min) to achieve similar MAP targets 1, 3.
Practical Dosing Framework
Norepinephrine 15 mcg/min (approximately 0.2 mcg/kg/min in a 70 kg patient) typically requires epinephrine 7-15 mcg/min (0.1-0.2 mcg/kg/min) for equivalent blood pressure support 1, 3
Start conservatively with epinephrine at 2-5 mcg/min and titrate up based on response rather than attempting to calculate an exact equivalent dose 1, 2
Important Clinical Caveats
Ensure adequate volume resuscitation before and during the transition, as both vasopressors can cause severe organ hypoperfusion in hypovolemic patients despite "normal" blood pressure 1. The patient should have received at least 30 mL/kg crystalloid bolus before vasopressor initiation 1.
When to Reconsider the Transition
If the patient requires norepinephrine >15 mcg/min, consider adding vasopressin (0.03-0.04 units/min) or a second agent rather than switching to epinephrine alone 1
In cardiogenic shock specifically, the combination of norepinephrine-dobutamine is superior to epinephrine alone, with better splanchnic perfusion, lower heart rates, fewer arrhythmias, and improved lactate clearance 3
Epinephrine should be reserved for situations where norepinephrine has failed or specific clinical scenarios (anaphylaxis, beta-blocker toxicity, cardiac arrest) rather than as a routine alternative 1, 3
Administration Route
Maintain central venous access throughout the transition to minimize extravasation risk, as both agents can cause severe tissue necrosis if infiltration occurs 1, 2. If extravasation occurs with either agent, infiltrate phentolamine 5-10 mg diluted in 10-15 mL saline at the site immediately 1.
Alternative Strategy: Adding Rather Than Switching
Consider adding epinephrine 2-5 mcg/min to the existing norepinephrine rather than switching completely, as combination therapy may provide better hemodynamic support in refractory shock 1. This approach is supported by guidelines recommending addition of epinephrine 0.1-0.5 mcg/kg/min when norepinephrine alone is insufficient 1.