What is the appropriate dosing range for norepinephrine (norepinephrine) intravenous (IV) infusion?

Appropriate Dosing Range for Norepinephrine IV Infusion

The appropriate dosing range for norepinephrine intravenous infusion is 0.1-1.0 mcg/kg/min, titrated to desired clinical effect, with doses up to 5 mcg/kg/min sometimes necessary in severe shock. 1

Initial Dosing and Titration

Norepinephrine is primarily used for shock states after adequate volume resuscitation. The dosing should follow this algorithm:

1. Starting dose: Begin at 0.1 mcg/kg/min
2. Titration: Gradually increase dose based on hemodynamic response
3. Target: Achieve mean arterial pressure (MAP) ≥65 mmHg
4. Typical range: 0.1-1.0 mcg/kg/min
5. Maximum dose: Up to 5 mcg/kg/min may be required in severe, refractory shock

Preparation and Administration

Norepinephrine should be administered through a central venous catheter whenever possible to minimize risk of extravasation. However, recent evidence suggests peripheral administration may be safe with proper protocols 2.

Standard preparation methods:

• Add 4 mg (4 mL) of norepinephrine to 250 mL D5W or NS to yield 16 mcg/mL
• Alternative concentration: 1 mg in 100 mL saline (10 mcg/mL)

Clinical Scenarios and Dosing Considerations

Cardiogenic/Distributive Shock

• Pediatric dosing: 0.1-1.0 mcg/kg/min 1
• Adult dosing: Same range, with careful titration to effect

Septic Shock

• Early administration (within 1-2 hours) at low doses improves shock control rate by 6 hours 3
• Target MAP of 75 mmHg may optimize renal perfusion, filtration and oxygenation compared to lower targets 4

Refractory Hypotension

• For hypotension unresponsive to initial doses, consider:
  • Increasing norepinephrine up to 5 mcg/kg/min
  • Adding a second vasopressor agent
  • Addressing underlying cause

Monitoring and Safety Considerations

Required Monitoring

• Continuous blood pressure monitoring
• Heart rate and rhythm
• Urine output
• Peripheral perfusion
• Serum lactate (when available)

Potential Complications

• Extravasation can result in severe tissue injury
  • If extravasation occurs, consider phentolamine (0.1-0.2 mg/kg up to 10 mg diluted in 10 mL NS) injected intradermally at the site 1
• Tachyarrhythmias/ectopic beats
• Peripheral, renal, and splanchnic vasoconstriction at higher doses (>20 mcg/kg/min) 1

Special Populations

Obesity

Weight-based dosing in obese patients may lead to higher cumulative norepinephrine requirements and prolonged vasopressor duration compared to non-weight-based approaches, without improving time to target MAP 5. Consider ideal body weight for dosing calculations in significantly obese patients.

Pediatric Patients

• Dosing range remains 0.1-1.0 mcg/kg/min, titrated to effect
• Maximum doses up to 5 mcg/kg/min may be necessary in severe shock 1

Clinical Pearls and Pitfalls

• Critical pitfall: Administering norepinephrine before adequate volume resuscitation may worsen tissue perfusion
• Important consideration: Norepinephrine effects are dose-dependent; higher doses (>1 mcg/kg/min) predominantly stimulate α-adrenergic receptors causing vasoconstriction
• Safety measure: Always use an infusion pump for administration
• Weaning strategy: Once the patient is stable, gradually reduce the dose by 0.05-0.1 mcg/kg/min while monitoring hemodynamic response

Norepinephrine remains the first-line vasopressor for most shock states, and proper dosing is essential for optimizing outcomes while minimizing adverse effects.