⚠️ Medical Disclaimer: This calculator is for educational and verification purposes only. It should not replace clinical judgment or official institutional protocols. Always double-check calculations before administering medication.
Required Flow Rate
0 mL/hr
Understanding the Norepinephrine Drip Rate Calculation
Norepinephrine (often referred to by the brand name Levophed) is a potent vasopressor commonly used in critical care settings to treat severe hypotension and shock. Calculating the correct infusion rate is critical for patient safety, as the drug has a narrow therapeutic index and potent effects on blood pressure.
This calculator determines the infusion pump setting (mL/hr) based on the patient's weight, the desired dose in micrograms per kilogram per minute (mcg/kg/min), and the concentration of the prepared IV solution.
The Calculation Formula
The math behind converting a weight-based dose to a volumetric flow rate involves two main steps: determining the concentration of the solution and then solving for the rate.
1. Calculate Concentration (mcg/mL):
(Total Drug mg × 1000) ÷ Total Volume mL
While concentrations can vary by institution, common standard preparations include:
Standard Concentration: 4 mg in 250 mL (16 mcg/mL)
Double Strength: 8 mg in 250 mL (32 mcg/mL)
Quad Strength: 16 mg in 250 mL (64 mcg/mL)
Typical dosing ranges for norepinephrine start at 0.01–0.05 mcg/kg/min and can be titrated upwards based on the patient's Mean Arterial Pressure (MAP) response. High doses typically exceed 0.5–1.0 mcg/kg/min, though refractory shock may require significantly higher rates.
Clinical Considerations
When administering norepinephrine, ensure central venous access is established whenever possible to prevent extravasation and tissue necrosis. Continuous monitoring of blood pressure via an arterial line is the standard of care to ensure accurate titration and prevent hypertensive complications.
function calculateDripRate() {
// Get input values using var
var weight = parseFloat(document.getElementById('patientWeight').value);
var dose = parseFloat(document.getElementById('targetDose').value);
var drugMg = parseFloat(document.getElementById('drugAmount').value);
var volumeMl = parseFloat(document.getElementById('bagVolume').value);
var resultArea = document.getElementById('result-area');
var rateDisplay = document.getElementById('flowRateResult');
var concDisplay = document.getElementById('concentrationResult');
// Validation
if (isNaN(weight) || isNaN(dose) || isNaN(drugMg) || isNaN(volumeMl)) {
alert("Please enter valid numbers in all fields.");
return;
}
if (weight <= 0 || drugMg <= 0 || volumeMl <= 0) {
alert("Weight, drug amount, and volume must be greater than zero.");
return;
}
// Logic
// 1. Calculate concentration in mcg/mL
// Total mcg = mg * 1000
var totalMcg = drugMg * 1000;
var concentrationMcgPerMl = totalMcg / volumeMl;
// 2. Calculate dose per minute in mcg
var dosePerMinute = dose * weight;
// 3. Calculate dose per hour in mcg (this is what the pump needs to deliver)
var dosePerHour = dosePerMinute * 60;
// 4. Calculate Rate in mL/hr
var rateMlPerHour = dosePerHour / concentrationMcgPerMl;
// Display results
resultArea.style.display = "block";
// Round to 1 decimal place for the pump setting
rateDisplay.innerHTML = rateMlPerHour.toFixed(1) + " mL/hr";
// Show the calculated concentration for verification
concDisplay.innerHTML = "Solution Concentration: " + concentrationMcgPerMl.toFixed(1) + " mcg/mL";
}