What is the starting dose for a norepinephrine (norepinephrine) drip in treating hypotension?

Norepinephrine Starting Dose for Hypotension

Start norepinephrine at 0.02 mcg/kg/min (approximately 8-12 mcg/min or 0.5 mg/h in a 70 kg adult), administered as a continuous IV infusion, preferably through central venous access, while simultaneously ensuring adequate fluid resuscitation with at least 30 mL/kg crystalloid bolus. 1, 2, 3

Initial Dosing Parameters

The FDA-approved starting regimen involves diluting 4 mg of norepinephrine in 1000 mL of 5% dextrose solution (yielding 4 mcg/mL concentration), then initiating at 2-3 mL/min (8-12 mcg/min) and titrating to effect. 3 Alternative weight-based dosing recommendations range from 0.02 mcg/kg/min 1 to 0.1-0.5 mcg/kg/min 2, 4, with the lower end being more appropriate for initial therapy.

Standard Concentration Preparation

• Add 4 mg norepinephrine to 250 mL D5W to create 16 mcg/mL concentration 2
• Alternatively, use the FDA standard of 4 mg in 1000 mL D5W for 4 mcg/mL concentration 3
• Never dilute in saline alone - dextrose-containing solutions are essential to prevent oxidation and loss of potency 3

Critical Pre-Administration Requirements

Address hypovolemia FIRST with a minimum 30 mL/kg crystalloid bolus before or concurrent with norepinephrine initiation. 2, 4 This is a strong recommendation with moderate quality evidence from the Surviving Sepsis Campaign. 2 The only exception is profound, life-threatening hypotension (systolic <70 mmHg) where norepinephrine should be started emergently while fluid resuscitation continues simultaneously. 2

Fluid Resuscitation Specifics

• Use balanced crystalloids (lactated Ringer's, Plasma-Lyte) preferentially over normal saline 1
• In pregnant patients with sepsis, consider more restrictive initial boluses (1-2 L) due to lower colloid oncotic pressure and higher pulmonary edema risk 1
• Never use hydroxyethyl starch (HES) - it increases mortality (51% vs 43%, p=0.03) and causes renal injury 2

Administration Route and Monitoring

Central venous access is strongly preferred to minimize extravasation risk and tissue necrosis. 2, 4, 3 However, if central access is unavailable or delayed, peripheral IV administration can be used temporarily with strict monitoring. 1, 2

Monitoring Protocol

• Place arterial catheter as soon as practical for continuous blood pressure monitoring 2, 4
• Check blood pressure every 5-15 minutes during initial titration 2
• Monitor tissue perfusion markers: lactate clearance, urine output (goal >50 mL/h), mental status, capillary refill 2

Target Blood Pressure and Titration

Target mean arterial pressure (MAP) of 65 mmHg is the standard goal for septic shock. 1, 2, 4 In previously hypertensive patients, avoid raising systolic BP more than 40 mmHg below their baseline. 3 Patients with chronic hypertension or atherosclerosis may require higher MAP targets. 2

Titration Strategy

• Increase by 0.5 mg/h every 4 hours as needed 2
• Typical maintenance range: 2-4 mcg/min (0.5-1 mL/min of standard dilution) 3
• Maximum doses can reach 68 mg/day in refractory cases, though occult hypovolemia should always be suspected at high doses 3

Escalation for Refractory Hypotension

When norepinephrine reaches 0.1-0.25 mcg/kg/min and hypotension persists, add vasopressin 0.03-0.04 units/min as second-line therapy rather than continuing to escalate norepinephrine alone. 1, 2 This approach is supported by the Surviving Sepsis Campaign guidelines. 2

Additional Vasopressor Options

• Epinephrine 0.1-0.5 mcg/kg/min can be added if vasopressin is insufficient 2
• Avoid dopamine - it is associated with higher mortality and arrhythmias compared to norepinephrine 2
• Phenylephrine is NOT recommended except in specific circumstances (e.g., norepinephrine causing serious arrhythmias) 2

Special Populations

Obese Patients

• Require lower weight-based doses (0.09 vs 0.13 mcg/kg/min) but similar absolute doses compared to non-obese patients 5
• Consider using non-weight-based dosing (8-12 mcg/min starting dose) to avoid underdosing 5

Pregnant Patients

• Start at 0.02 mcg/kg/min with target MAP 65 mmHg 1
• Consider adding vasopressin 0.04 units/min for refractory shock, with fetal monitoring when appropriate 1
• Theoretical oxytocin receptor interaction with vasopressin is not a contraindication 1

Critical Pitfalls to Avoid

• Never start norepinephrine without addressing hypovolemia - vasoconstriction in hypovolemic patients causes severe organ hypoperfusion despite "normal" blood pressure 2
• Do not mix with sodium bicarbonate or alkaline solutions - adrenergic agents are inactivated in alkaline solutions 2, 3
• If extravasation occurs, immediately infiltrate 5-10 mg phentolamine diluted in 10-15 mL saline into the site to prevent tissue necrosis 2, 4, 3
• Avoid excessive fluid resuscitation - early norepinephrine administration can prevent fluid overload while maintaining perfusion 6, 7