Norepinephrine 8mg Dilution: Initial Rate and Titration Protocol
Standard Preparation for 8mg Dilution
Add 8 mg of norepinephrine to 250 mL of D5W to yield a concentration of 32 mcg/mL 1. This is double the standard 4mg/250mL concentration but follows the same dilution principles outlined in the FDA label 1.
Initial Running Rate
Start the infusion at 2-3 mL/hour (approximately 1-1.5 mcg/min or 0.015-0.02 mcg/kg/min for a 70kg adult) 2, 1. The FDA label recommends an initial dose of 2-3 mL per minute of the standard 4 mcg/mL solution (8-12 mcg base per minute) 1, but with your 32 mcg/mL concentration, you must adjust proportionally to achieve the same dosing range.
- For a 32 mcg/mL concentration, 2-3 mL/hour delivers approximately 1-1.5 mcg/min 1
- This translates to 0.1-0.5 mcg/kg/min for a 70kg adult, which aligns with guideline recommendations 2, 3
Titration Protocol
Titrate by 0.5-1 mL/hour increments every 5-15 minutes to achieve a target MAP of 65 mmHg 2, 4.
- Monitor blood pressure and heart rate every 5-15 minutes during initial titration 2
- Adjust dose to maintain MAP 65-100 mmHg sufficient for vital organ perfusion 3, 4
- In previously hypertensive patients, raise blood pressure no higher than 40 mmHg below pre-existing systolic pressure 1
Maintenance dosing typically ranges from 0.5-1 mL/hour (1-2 mcg/min or 2-4 mcg base) with your 32 mcg/mL concentration 1. This corresponds to the FDA label's recommended maintenance range of 0.5-1 mL per minute of standard 4 mcg/mL solution 1.
Critical Pre-Administration Requirements
Correct hypovolemia with a minimum 30 mL/kg crystalloid bolus before or concurrent with norepinephrine initiation 2, 4. In severe hypotension (systolic <70 mmHg), start norepinephrine as an emergency measure while fluid resuscitation continues 2.
Administration Route
Use central venous access whenever possible to prevent tissue necrosis from extravasation 2, 3, 1. If central access is unavailable, peripheral IV can be used temporarily with strict monitoring 2.
Monitoring Parameters
- Hemodynamic targets: MAP ≥65 mmHg 2, 4
- Tissue perfusion markers: Lactate clearance, urine output >50 mL/h, mental status, capillary refill 2, 4
- Continuous arterial line monitoring is recommended for all patients requiring vasopressors 3, 4
Escalation Strategy
If norepinephrine reaches 0.25 mcg/kg/min (approximately 8-10 mL/hour with your concentration) and hypotension persists, add vasopressin 0.03-0.04 units/min as second-line therapy 2, 4. Do not continue escalating norepinephrine alone beyond this point 2.
Critical Safety Considerations
If extravasation occurs, immediately infiltrate 5-10 mg of phentolamine diluted in 10-15 mL of saline into the affected site 2, 3, 1. This prevents tissue necrosis and sloughing 2.