How should Levophed (norepinephrine) be used to manage hypotension?

Management of Hypotension with Levophed (Norepinephrine)

Norepinephrine (Levophed) should be used as the first-choice vasopressor for managing hypotension, particularly in septic shock, with an initial target mean arterial pressure (MAP) of 65 mmHg. 1

Initial Assessment and Fluid Resuscitation

Before initiating norepinephrine:

• Assess for hypovolemia, as norepinephrine should not be given to patients who are hypotensive from blood volume deficits except as an emergency measure 2
• Administer crystalloid fluid resuscitation (minimum 30 mL/kg) if hypovolemia is suspected 1
• Continue fluid administration as long as hemodynamic parameters improve 1

Administration Protocol

Route and Preparation

• Administer through a central venous catheter whenever possible 3, 2
• If central access is unavailable, peripheral administration can be used for short-term therapy (<24 hours) with careful monitoring 3
• Dilute in dextrose solution; standard concentration is 4 mcg/mL 2

Dosing

1. Starting dose: 0.1-0.5 mcg/kg/min (typically 2-4 mcg/min) 3, 2
2. Titration: Adjust based on patient response to maintain MAP ≥65 mmHg 1
3. Maintenance: Average dose ranges from 2-4 mcg/min, but may require higher doses in refractory cases 2
4. Weaning: Reduce gradually to avoid abrupt withdrawal when adequate blood pressure and tissue perfusion are maintained 2

Monitoring During Administration

• Continuous cardiac monitoring
• Frequent blood pressure measurements (arterial line preferred) 1
• Place arterial catheter as soon as practical for continuous BP monitoring 1
• Monitor for signs of tissue perfusion (urine output, mental status, lactate levels)
• Watch for extravasation if administered peripherally 3

Special Considerations

Adjunctive Vasopressors

If target MAP cannot be achieved with norepinephrine alone:

• Add vasopressin (up to 0.03 U/min) to either raise MAP or decrease norepinephrine dosage 1
• Add epinephrine as an alternative second agent when additional support is needed 1
• Consider dopamine only in highly selected patients with low risk of tachyarrhythmias and bradycardia 1
• Avoid phenylephrine except in specific circumstances: when norepinephrine causes serious arrhythmias, when cardiac output is high with persistent hypotension, or as salvage therapy 1

Patient-Specific Considerations

• In previously hypertensive patients, target a MAP no higher than 40 mmHg below the preexisting systolic pressure 2
• In patients with poor cardiac contractility, norepinephrine can increase cardiac output through increased cardiac preload and contractility 4
• However, in patients with baseline LVEF ≤45%, achieving MAP ≥75 mmHg may not further improve cardiac output 4

Potential Complications

• Tachyarrhythmias and increased myocardial oxygen consumption 3
• Tissue ischemia from excessive vasoconstriction 2
• Decreased renal perfusion if used without adequate volume resuscitation 2
• Tissue necrosis if extravasation occurs 3

Clinical Pearls

• Early administration of norepinephrine in severely hypotensive patients can increase cardiac output through improved cardiac preload and contractility 4
• Recent evidence suggests prophylactic norepinephrine may reduce complications in high-risk surgical patients 5
• Norepinephrine is approximately 13 times more potent than phenylephrine for blood pressure control 6
• Avoid using norepinephrine during cyclopropane and halothane anesthesia due to risk of ventricular arrhythmias 2

By following this structured approach to norepinephrine administration, clinicians can effectively manage hypotension while minimizing potential adverse effects.