Converts norepinephrine dose in µg/kg/min to infusion rate in mL/hour.
Primary source: Российские КР по сепсису и септическому шоку (Минздрав РФ, 2022). Surviving Sepsis Campaign 2021. Стандартные разведения по протоколам ОРИТ.
Standard for a syringe pump is 50 mL; for an infusion pump, often 250 mL
mL
STANDARD INFUSION
Calculated values
Visual drip rhythm
The animation blinks exactly at the calculated drop interval.
About this score
Norepinephrine (NA) is the first-line vasopressor for septic shock and other vasoplegic shock states. The Surviving Sepsis Campaign 2021 guidelines recommend norepinephrine as the initial vasopressor, targeting a mean arterial pressure (MAP) ≥ 65 mm Hg.
ICU orders are written as a dose in µg/kg/min, but the infusion pump is programmed in mL/hour, hence the need for conversion. Formula: rate (mL/hour) = (dose × weight × 60) / concentration (µg/mL). Concentration is calculated as (drug mg × 1000) / solution volume in mL.
Common dilutions: 4 mg norepinephrine bitartrate (one 0.2% ampoule, 2 mL) in 50 mL normal saline for a syringe pump (concentration 80 µg/mL), or 16 mg in 250 mL (64 µg/mL) for a volumetric infusion pump. Therapeutic range: 0.05–0.5 µg/kg/min; above 0.5 µg/kg/min, add fixed-dose vasopressin 0.03 units/min rather than continuing to titrate norepinephrine; above 1 µg/kg/min, consider epinephrine and hydrocortisone 200 mg/day.
When to use
Septic shock, after initial fluid resuscitation with 30 mL/kg crystalloids, if hypotension persists.
Cardiogenic shock with a predominant vasoplegic component (post-MI, post-cardiac surgery).
Anaphylactic shock, after the first epinephrine bolus, if hypotension persists.
Hypotension after spinal/epidural anesthesia with inadequate response to ephedrine/phenylephrine.
Parameters in detail
Patient weight
Patient's body weight in kilograms. In morbidly obese patients, consider using ideal or adjusted body weight, depending on institutional protocol.
Norepinephrine dose
Target dose in µg/kg/min. Starting dose 0.05; therapeutic range 0.1–0.5; high dose 0.5–1.0; critical dose > 1.0. Titrate every 2–5 minutes based on SBP.
Drug in solution
Amount of norepinephrine in the prepared solution. Standard is 4 mg (one 0.2% ampoule, 2 mL) or 8/16 mg for concentrated dilutions.
Solution volume
Volume of carrier solution (normal saline or 5% dextrose). Standard for a syringe pump is 50 mL; for a volumetric infusion pump, 100 or 250 mL.
Clinical example
Case
70-year-old man with septic shock due to community-acquired pneumonia. Weight 80 kg. After 2.4 L of Ringer's solution, BP remains 78/45 (mean 56). Norepinephrine is started at 0.1 µg/kg/min. Prepared dilution: 4 mg in 50 mL normal saline (standard syringe pump).
Calculation
Concentration: 4 mg × 1000 / 50 mL = 80 µg/mL. Rate: 0.1 × 80 × 60 / 80 = 6 mL/hour. Set the syringe pump to 6 mL/hour.
Interpretation and management
Therapeutic starting dose. Plan: check BP every 5 minutes; if target SBP ≥ 65 is not reached, titrate by 0.02–0.05 µg/kg/min. In parallel: assess adequacy of fluid resuscitation (CVP, lactate, urine output ≥ 0.5 mL/kg/h), blood cultures, broad-spectrum antibiotics within the first hour. At doses > 0.5 µg/kg/min, add vasopressin 0.03 units/min.
Limitations and cautions
Norepinephrine requires reliable venous access, preferably central (risk of extravasation and tissue necrosis with peripheral administration).
Use with caution in patients with severe bradycardia or high-degree AV block; the α-adrenergic effect may worsen reflex bradycardia.
In hypovolemic shock (hemorrhage, dehydration), this is a symptomatic measure, not treatment of the underlying cause; source control must proceed in parallel.
The calculator does not replace clinical judgment: patient response to a standard dose varies, and titration based on clinical status (BP, lactate, perfusion) is always required.
Frequently asked questions
Which dilution should I choose, 4 mg/50 mL or 16 mg/250 mL?
4 mg/50 mL (80 µg/mL) is the standard syringe pump dilution, convenient for frequent titration and low doses. 16 mg/250 mL (64 µg/mL) suits a high-volume infusion pump and is convenient for a stable high dose. The concentrations are nearly equal; choose based on available equipment.
Can norepinephrine be given through a peripheral line?
Yes, as a temporary measure until central access is obtained, but for no more than 6 hours and at a concentration no higher than 16 µg/mL (= 4 mg in 250 mL). If extravasation occurs, stop the infusion immediately and infiltrate the area with phentolamine 5–10 mg in 10–15 mL normal saline.
When should vasopressin be added?
At a norepinephrine dose > 0.25–0.5 µg/kg/min (Surviving Sepsis Campaign 2021). Vasopressin is added at a fixed dose of 0.03 units/min. This reduces norepinephrine requirements and the risk of arrhythmias.
How often should the dose be recalculated?
After every update to the recorded weight or the dilution, or after a significant hemodynamic change. Modern infusion pumps can calculate this automatically when patient and drug parameters are entered correctly.
What should be done at doses > 1 µg/kg/min?
This indicates severe vasoplegic shock. Approach: (1) confirm adequate fluid resuscitation and source control, (2) add vasopressin, (3) start hydrocortisone 200 mg/day as a continuous infusion, (4) consider epinephrine or angiotensin II. Prognosis is serious; discuss with the family.
All clinical calculators in one place
Validated scores and formulas with full interpretation, clinical examples and source references. Open access, no registration required.
65+ calculators · scores and formulas · interpretation with management notes
Aleksandr A. Aulov
Physician, internal medicine, Sechenov School — independent medical education platform.
Calculators are compiled from the original publications and current clinical guidelines. Interpretation thresholds follow the source study unless stated otherwise.
This calculator is intended for healthcare professionals. Do not use it for self-diagnosis or self-treatment. Management decisions are made by the treating clinician based on the full clinical picture of the individual patient.
Last clinical review: April 28, 2026 ·
Author: Aleksandr A. Aulov,
MD, internal medicine ·
Primary source: Российские КР по сепсису и септическому шоку (Минздрав РФ, 2022). Surviving Sepsis Campaign 2021. Стандартные разведения по протоколам ОРИТ.