Vasopressor Selection in Emergency Medicine

Pharmacological Differences

Norepinephrine increases mean arterial pressure (MAP) primarily through vasoconstriction with minimal changes in heart rate and stroke volume, while epinephrine increases MAP and cardiac output through increased stroke volume and heart rate 2, 3
Epinephrine may increase aerobic lactate production via stimulation of skeletal muscles' β2-adrenergic receptors, potentially interfering with the use of lactate clearance to guide resuscitation 1, 2

Norepinephrine is recommended as the first-line vasopressor for septic shock based on evidence showing lower mortality and fewer adverse events compared to dopamine 1, 2
Norepinephrine is more potent than dopamine and more effective at reversing hypotension in septic shock patients 2, 3
Norepinephrine is associated with significantly fewer arrhythmias compared to dopamine (RR 0.35; 95% CI 0.19-0.66 for ventricular arrhythmias) 1, 3
Epinephrine should be considered the first alternative to norepinephrine in septic shock when norepinephrine is unavailable or ineffective 1, 2
Despite concerns about splanchnic circulation effects, randomized trials comparing norepinephrine to epinephrine found no significant differences in mortality (RR 0.96; 95% CI 0.77-1.21) 1, 2

Epinephrine is recommended during cardiopulmonary resuscitation to increase return of spontaneous circulation (ROSC) 5, 6
The 2015 International Consensus on Cardiopulmonary Resuscitation recommends standard-dose epinephrine (1 mg) for cardiac arrest (weak recommendation, very low-quality evidence) 5, 6

In pediatric septic shock, epinephrine may be more effective than dopamine for shock resolution in the first hour (OR 4.8; 95% CI 1.3-17.2) 7
Selection of vasopressors in pediatric patients should be tailored to individual physiology and clinical response 7

Norepinephrine is typically administered as an intravenous infusion into a large vein, preferably through a central venous catheter 4
When infusion pumps are unavailable (resource-limited settings), dopamine or epinephrine can be diluted in crystalloid solution and administered using a drop regulator with frequent monitoring of blood pressure and heart rate 4

Norepinephrine: Generally fewer arrhythmias compared to epinephrine or dopamine, but still requires careful monitoring for hypertension and tissue ischemia 1, 2
Extravasation of either agent can cause local tissue necrosis; infusion sites should be frequently checked 4