Pressors

Pressor Mechanism Typical starting dose Indication Side effects
Levophed (norepinephrine) β1 (inotropy/chronotropy) (lower doses)
α1 (vasoconstriction) (higher doses)		 [0.02 - 0.15] mcg/kg/min First-line vasopressor in septic, cardiogenic, hypovolemic shock ↓ splanchnic, renal flow
Vasopressin V1 (vasoconstriction)
V2 (anti-diuretic hormone - fluid retention)

[0.04-0.06] U/min

Use to reduce requirement for other pressors - not first-line. Pure vasoconstrictor - may decrease SV, CO in poorly functioning heart; ischemia in vascular disease

↓ splanchnic flow
Phenylephrine α1 (vasoconstriction) [0.5 - 1.0] mcg/kg/min Pure vasoconstrictor - use when tachy (causes reflex bradycardia) and can't use levo reflex bradycardia
Dobutamine β1 (inotropy/chronotropy)
β2		 [0.5 - 20] mcg/kg/min Cardiogenic shock/RV failure (add levo if need to increase BP) transient ↓ SVR (β2 agonist)
Milrinone PDE inhibitor - inotrope + vasodilation   Short term for cardiogenic shock  
Epinephrine β1 (inotropy/chronotropy) (lower doses)
α1 (vasoconstriction) (higher doses)
β2		 [0.05-2.0] mcg/kg/min
 Anaphylaxis ↓ splanchnic flow
tachydysrhythmias
Dopamine

D
β1 (inotropy/chronotropy)
α1 (vasoconstriction) (higher doses)

 [0.5 - 2.0] mcg/kg/min - D1 
[5 - 10] mcg/kg/min - β1
[> 10] mcg/kg/min - α1		 Bradycardic cardiovascular collapse (high-dose dopamine) ↓ splanchnic flow
tachydysrhythmias

Mechanisms of action

  • α1 (vascular walls) - Vasoconstriction
  • β1 (heart) - Inotropy, chronotropy. ↑ CO, ↑ HR, unchanged or ↓ BP
  • β2 - dilate small arteries of heart, visceral organs, skeletal muscle; bronchodilation
  • V1 - vasoconstriction of small arterioles
  • Dopamine - 
    • D1, D2 - renal diuresis/natriuresis
    • D4 - ↑ cardiac contractility, ↑ HR
  1st-line 2nd-line
Anaphylactic Epinephrine - 1 ml of 1:10,000 = 100 mcg, then 0.02 mcg/kg/min norepinephrine 0.1-1.0 mcg/kg/min
Cardiogenic (LV) SBP > 90 - dobutamine 2-20 mcg/kg/min
SBP 70-90 - dopamine 15 mcg/kg/min
SBP < 70 - norepinephrine		 milrinone 50 mcg/kg loading dose, then 5-10 mcg/kg/min (not recommended post-MI)
Cardiogenic (PE) dobutamine 5 mcg/kg/min
norepinephrine 0.1-1.0 mcg/kg/min		 phenylephrine 10-20 mcg/kg/min
Hemorrhaghic volume resuscitation dopamine 5-15 mcg/kg/min (temporizing adjunct)
Neurogenic dopamine 5-15 mcg/kg/min (inotropy + chronotropy) norepinephrine 0.1-1.0 mcg/kg/min
phenylephrine 10-20 mcg/kg/min (side effect of reflex bradycardia)
Septic norepinephrine 0.1-1.0 mcg/kg/min
dobutamine 5 mcg/kg/min		 epinephrine 0.02 mcg/kg/min

Complications

  • Should give through central line!
    • Peripheral extravasation → local vasoconstriction and necrosis - treat with local subq phentolamine (α-antagonist) (5-10 mg in 10 mL saline) 
  • Hypoperfusion (excessive vasoconstriction, esp. splanchnic)
    • Mesenteric ischemia - hold enteral nutrition with high pressors
    • Finger/toe duskiness/necrosis
    • Renal insufficiency, gastritis, shock liver, etc.
  • Pressors don't work as well in setting of acidosis (maybe? decreased beta receptor expression?)
author: admin | last edited: June 13, 2018, 4:18 p.m. | pk: 67

  1. Vasopressors and inotropes in shock