What is the recommended dosage of noradrenaline (norepinephrine) for treating severe hypotension?

Norepinephrine (Noradrenaline) Dosage for Severe Hypotension

The recommended initial dosage of norepinephrine for treating severe hypotension is 0.05-0.1 μg/kg/min, which can be titrated by 0.05-0.1 μg/kg/min every 5-15 minutes to achieve a target mean arterial pressure (MAP) of at least 65 mmHg. 1

Dosing Guidelines

Initial Dosing

• FDA-approved initial dose: 8-12 mcg/min (0.25-0.375 mL/min of standard concentration) 2
• Critical care guidelines recommend:
  • 0.05-0.1 μg/kg/min as starting dose 1
  • For a 70-kg adult, this equals approximately 7-35 mcg/min 3

Maintenance Dosing

• Average maintenance dose: 2-4 mcg/min (0.0625-0.125 mL/min) 2
• Titrate to maintain MAP ≥65 mmHg or systolic BP 80-100 mmHg 3, 1
• Higher MAP targets (e.g., 80-85 mmHg) may be appropriate for patients with chronic hypertension 4

Maximum Dosing

• No absolute maximum dose is specified in guidelines
• Doses exceeding 4 μg/kg/min have been used safely in refractory septic shock 5
• Titrate based on clinical response and hemodynamic parameters

Administration Considerations

Route of Administration

• Central venous access is strongly preferred 3, 1
• Peripheral or intraosseous administration may be used temporarily in emergencies but carries risk of extravasation 6

Preparation and Compatibility

• Do not mix with sodium bicarbonate or alkaline solutions (inactivates norepinephrine) 3
• Administer through dedicated line when possible

Monitoring During Administration

• Continuous blood pressure monitoring
• Heart rate, urine output (target >0.5 mL/kg/hr)
• Skin perfusion and mental status
• Lactate clearance as marker of tissue perfusion 1

Important Precautions

Extravasation Risk

• If extravasation occurs, infiltrate site with 5-10 mg phentolamine diluted in 10-15 mL saline to prevent tissue necrosis 3, 1

Volume Status

• Ensure adequate fluid resuscitation before and during norepinephrine administration
• Initial fluid challenge of at least 30 mL/kg crystalloid is recommended before starting vasopressors 1
• Norepinephrine is relatively contraindicated in hypovolemia 3

Cardiac Considerations

• May increase myocardial oxygen requirements - use cautiously in patients with ischemic heart disease 3
• Monitor for arrhythmias, especially in patients with underlying cardiac disease 2

Timing of Initiation

Early administration of norepinephrine (simultaneously with fluid resuscitation) should be considered in:

• Profound hypotension (e.g., diastolic BP ≤40 mmHg) 7
• High diastolic shock index (heart rate/diastolic BP ≥3) 7
• Patients at risk for fluid overload 7

Early norepinephrine administration has been associated with:

• Increased shock control rate (76.1% vs 48.4% at 6 hours) 8
• Lower incidence of cardiogenic pulmonary edema 8
• Reduced risk of fluid overload 7

Adjunctive Therapies

If hypotension persists despite norepinephrine:

• Consider adding vasopressin (0.03 U/min) to either raise MAP or decrease norepinephrine dosage 1
• Consider dobutamine (2.5-20 μg/kg/min) if there is evidence of myocardial dysfunction or persistent hypoperfusion despite adequate blood pressure 1
• Consider hydrocortisone (up to 300 mg/day) in patients requiring escalating vasopressor doses 1