How should norepinephrine (noradrenaline) be prescribed as an intravenous continuous infusion for an adult patient with hypotension or shock?

How to Prescribe Norepinephrine (Noradrenaline)

Start norepinephrine at 0.1–0.5 mcg/kg/min (7–35 mcg/min in a 70-kg adult) via central line whenever possible, diluted in 5% dextrose, and titrate to maintain mean arterial pressure ≥65 mmHg or systolic blood pressure 80–100 mmHg. 1, 2

Preparation and Dilution

Norepinephrine must be diluted before administration. The standard preparation is adding 4 mg (4 mL vial) to 1,000 mL of 5% dextrose or 5% dextrose with sodium chloride, yielding a concentration of 4 mcg/mL. 2

• Never dilute in saline alone—dextrose-containing solutions protect against oxidation and loss of potency 1, 2
• Never mix with sodium bicarbonate or alkaline solutions—adrenergic agents are inactivated in alkaline environments 1
• Whole blood or plasma should be administered separately (e.g., via Y-connector) if volume resuscitation is needed concurrently 2

Route of Administration

Central venous access is strongly preferred to minimize the risk of tissue necrosis from extravasation. 1, 2

• If central access is unavailable, peripheral administration is acceptable for low doses (<0.5 mcg/kg/min) for <24 hours using large-bore (≥18-gauge) peripheral IV in the antecubital fossa, with meticulous monitoring every 2 hours 3
• Avoid leg veins, especially in elderly patients or those with peripheral vascular disease (atherosclerosis, diabetes), due to increased risk of gangrene 2
• Avoid catheter tie-in techniques as they promote stasis and increase local drug concentration 2

Dosing Strategy

Initial Dosing

Start at 8–12 mcg/min (2–3 mL/min of standard dilution) and titrate to effect. 2

Maintenance Dosing

Average maintenance: 2–4 mcg/min (0.5–1 mL/min) or 0.1–0.5 mcg/kg/min 1, 2

High-Dose Considerations

• Doses may occasionally need to be much higher (up to 68 mg/day or 17 vials has been reported) if hypotension persists 2
• Before escalating to high doses, always suspect and correct occult hypovolemia—central venous pressure monitoring is helpful 2
• When norepinephrine requirements exceed moderate levels, add vasopressin rather than continuing to escalate norepinephrine alone, as this reduces catecholamine-related complications 4, 5

Blood Pressure Targets

Target mean arterial pressure ≥65 mmHg or systolic blood pressure 80–100 mmHg to maintain perfusion to vital organs. 1, 2

• In previously hypertensive patients, do not raise blood pressure more than 40 mmHg below their baseline systolic pressure 2
• Recent evidence suggests that rigid MAP targets may not universally optimize outcomes—consider microcirculatory monitoring when available to guide individualized targets 6

Timing of Initiation

Start norepinephrine early when hypotension persists despite initial fluid resuscitation. 4, 5

• Volume depletion should be corrected as fully as possible before vasopressor administration 2
• However, in emergency situations where cerebral or coronary perfusion is threatened, norepinephrine can be started before or concurrent with volume replacement 2
• Early norepinephrine administration (rather than delayed) improves cardiac output, microcirculation, and avoids fluid overload 4

Monitoring Requirements

Continuous bedside monitoring is mandatory:

• Use IV drip chamber or infusion pump for accurate flow rate control 2
• Monitor blood pressure continuously or every 1–2 minutes during titration
• Check infusion site frequently for blanching, extravasation, or signs of ischemia 2
• Blanching along the vein may occur even without obvious extravasation due to vasa vasorum constriction—consider changing infusion site if this occurs 2

Critical Safety Considerations

Extravasation Management

If extravasation occurs, immediately infiltrate the site with 5–10 mg phentolamine diluted in 10–15 mL saline to prevent tissue necrosis and sloughing. 1

Contraindications and Cautions

• Relatively contraindicated in hypovolemia—correct volume status first 1
• Use cautiously in ischemic heart disease—may increase myocardial oxygen demand 1
• Contraindicated with cyclopropane or halothane anesthesia—risk of ventricular arrhythmias 2
• Extreme caution with MAO inhibitors or tricyclic antidepressants—may cause severe, prolonged hypertension 2

Special Populations

• Elderly patients: Start at lower end of dosing range; avoid leg veins 2
• Pregnancy: Use only if clearly needed (no adequate studies) 2
• Pediatric: Safety not established; if used, typical starting dose is 0.1 mcg/kg/min 1

Discontinuation

Reduce infusion gradually—avoid abrupt withdrawal. 2

• Continue until adequate blood pressure and tissue perfusion are maintained without therapy
• In some cases of vascular collapse (e.g., acute MI), treatment may be required for up to 6 days 2

Clinical Context

Norepinephrine is indicated for severe hypotension (systolic BP <70 mmHg) with low total peripheral resistance, most commonly in septic shock, post-cardiac arrest, or distributive shock states. 1 In sepsis specifically, norepinephrine improves renal blood flow and urine output despite its general tendency to cause renal and mesenteric vasoconstriction. 1