Norepinephrine Dosing Guidelines for Vasopressor Support
The standard dosing ranges for norepinephrine are: low dose (0.01-0.1 μg/kg/min), medium dose (0.1-0.5 μg/kg/min), and high dose (>0.5 μg/kg/min), with most patients responding to medium doses while maintaining adequate tissue perfusion.
Norepinephrine Dosing Recommendations
FDA-Approved Dosing
- Initial dose: 0.05-0.1 μg/kg/min (2-4 μg/min for average adult) 1
- Maintenance dose: 0.5-1 mL/min (2-4 μg/min of base) 1
- High dose: In some cases, much larger doses may be necessary, but occult blood volume depletion should always be suspected 1
Clinical Practice Dosing Categories
- Low dose: 0.01-0.1 μg/kg/min
- Medium dose: 0.1-0.5 μg/kg/min
- High dose: >0.5 μg/kg/min (with doses >2 μg/kg/min considered extremely high) 2
Administration Guidelines
Preparation
- Add 4 mg (4 mL) of norepinephrine to 1,000 mL of 5% dextrose solution, yielding a concentration of 4 μg/mL 1
- Administration via central venous access is strongly preferred to avoid extravasation 1
Titration Protocol
- Start at 0.05-0.1 μg/kg/min and titrate by 0.05-0.1 μg/kg/min every 5-15 minutes 2
- Target mean arterial pressure (MAP) of 65 mmHg for most patients 2
- In previously hypertensive patients, target a systolic blood pressure no higher than 40 mmHg below the preexisting systolic pressure 1
Special Considerations
Weight-Based vs. Non-Weight-Based Dosing
- Research shows no difference in time to goal MAP between weight-based and non-weight-based dosing in obese patients 3
- Obese patients may require lower weight-based doses (0.09 μg/kg/min) compared to non-obese patients (0.13 μg/kg/min), but similar absolute doses (9 μg/min vs. 8 μg/min) 4
Patient-Specific Factors
- Clearance of norepinephrine is negatively related to illness severity (SAPS II score) 5
- Half-life ranges from 2 minutes in less severe illness to 6.8 minutes in more severe illness 5
- Monitor for increased CVP during norepinephrine titration, as an increase >1.5 mmHg may predict decreased cardiac output 6
Monitoring and Safety
Monitoring Parameters
- Continuous blood pressure monitoring
- Urine output
- Mental status
- Skin perfusion
- Lactate clearance 2
Potential Adverse Effects
- Increased pulmonary vascular resistance and right ventricular afterload
- Tissue ischemia (especially with high doses)
- Tachyarrhythmias 2
Weaning Strategy
- Reduce gradually to avoid abrupt withdrawal and hypotension
- Begin weaning as soon as hemodynamic stabilization is achieved 2
Pitfalls to Avoid
- Using fixed dosing rather than titrating to effect
- Failing to correct hypovolemia before or during vasopressor therapy
- Delaying vasopressor initiation when indicated
- Not considering patient-specific factors that may affect dosing requirements 2
Norepinephrine remains the first-line vasopressor for shock management, with dosing requirements varying based on individual patient factors and shock etiology. Careful titration to target MAP while monitoring for signs of adequate tissue perfusion is essential for optimal outcomes.