How to prepare norepinephrine in normal saline (NS)?

Norepinephrine Preparation in Normal Saline

Norepinephrine can be prepared in normal saline (NS), though D5W remains the standard diluent; add 4 mg of norepinephrine to 250 mL of NS to yield a concentration of 16 μg/mL for standard adult use. 1

Standard Preparation Protocols

Adult Concentrations

• Standard concentration: Add 4 mg norepinephrine to 250 mL of D5W (or NS) to create 16 μg/mL 1
• Alternative lower concentration: Add 1 mg norepinephrine to 100 mL of saline for a 1:100,000 solution (10 μg/mL), particularly useful for anaphylaxis 1

Chemical Stability in Normal Saline

• Norepinephrine solutions prepared in NS at both 4 μg/mL and 16 μg/mL concentrations remain chemically stable for 7 days at room temperature under ambient light 2
• At 168 hours, norepinephrine retained 96.4% of baseline concentration when diluted in NS at both tested concentrations 2
• This stability is equivalent to D5W preparations, making NS an acceptable alternative diluent 2

Pediatric Preparation

• "Rule of 6" method: 0.6 × body weight (kg) = number of milligrams diluted to total 100 mL of saline; then 1 mL/h delivers 0.1 mcg/kg/min 1
• This provides a practical concentration for weight-based dosing in children 1

Critical Administration Considerations

Pre-Administration Requirements

• Address hypovolemia FIRST with crystalloid fluid boluses (minimum 30 mL/kg) before or concurrent with norepinephrine initiation 1
• Vasoconstriction in hypovolemic patients causes severe organ hypoperfusion despite "normal" blood pressure 1

Route Selection

• Central venous access is strongly preferred to minimize extravasation risk 1, 3
• Peripheral IV can be used temporarily if central access is unavailable or delayed, but requires strict monitoring 1

Compatibility Warning

• Never mix norepinephrine with sodium bicarbonate or other alkaline solutions in the IV line, as catecholamines are inactivated in alkaline solutions 1

Dosing After Preparation

• Start at 0.1-0.5 mcg/kg/min (7-35 mcg/min in a 70 kg adult) 1
• Titrate to target MAP of 65 mmHg for septic shock 1
• Monitor blood pressure and heart rate every 5-15 minutes during initial titration 1

Extravasation Management

• If extravasation occurs, immediately infiltrate phentolamine 5-10 mg diluted in 10-15 mL of saline into the affected site 1, 3
• Pediatric dose: 0.1-0.2 mg/kg up to 10 mg 1