What is the starting dose of norepinephrine (Levophed) for a patient with hypotension?

Starting Dose of Norepinephrine for Hypotension

The recommended starting dose of norepinephrine for a patient with hypotension is 0.5 mg/hour (approximately 0.05-0.1 μg/kg/min), which should be titrated every 4 hours by 0.5 mg/hour to a maximum of 3 mg/hour based on the patient's response. 1

Preparation and Administration

• Norepinephrine must be diluted in dextrose-containing solutions prior to infusion to prevent significant loss of potency due to oxidation 2
• Standard preparation: Add 4 mg (4 mL) of norepinephrine to 1,000 mL of 5% dextrose solution, resulting in a concentration of 4 mcg/mL 2
• Administration should be through a central venous line whenever possible to prevent tissue necrosis from extravasation 3
• For peripheral administration (when central access is not immediately available), use a large vein and monitor the site closely for extravasation 2

Dosing Strategy

• Initial dose: Start at 0.5 mg/hour (approximately 0.05-0.1 μg/kg/min) 1
• Titration: Increase by 0.5 mg/hour every 4 hours as needed 1
• Maximum dose: Up to 3 mg/hour, though higher doses may occasionally be necessary in refractory cases 1, 2
• Goal: Increase mean arterial pressure (MAP) by 10 mmHg or achieve urine output >50 mL/hour for at least 4 hours 1

Target Blood Pressure

• Target MAP of 65-100 mmHg, sufficient to maintain vital organ perfusion 3, 4
• In previously hypertensive patients, aim for a systolic blood pressure no higher than 40 mmHg below the preexisting systolic pressure 2
• Individualize MAP targets for patients with chronic hypertension, who may require higher targets 4

Monitoring During Administration

• Continuous hemodynamic monitoring is essential during administration 3
• Monitor for signs of extravasation; if it occurs, infiltrate 5-10 mg of phentolamine diluted in 10-15 mL of saline into the site 3
• Assess peripheral perfusion regularly (skin temperature, capillary refill) 3
• Monitor urine output as a marker of adequate renal perfusion 1

Important Clinical Considerations

• Always correct volume depletion before or concurrently with norepinephrine administration 2, 5
• Early administration of norepinephrine (within the first hours of shock) has been associated with improved outcomes, including better shock control and reduced fluid requirements 5, 6
• Consider adding vasopressin if hypotension is refractory to norepinephrine alone, preferably within the first 3 hours of norepinephrine initiation 4, 7
• When discontinuing, reduce the dose gradually by approximately 25% every 30 minutes as tolerated to avoid rebound hypotension 3

Cautions and Adverse Effects

• Norepinephrine may increase myocardial oxygen consumption, use cautiously in patients with ischemic heart disease 3
• Potential for tissue necrosis if extravasation occurs 3, 2
• Risk of cardiac arrhythmias, especially at higher doses 1, 3
• Doses >0.4 μg/kg/min are associated with significantly increased mortality and should prompt reassessment of the patient's condition 8

Special Situations

• For anaphylaxis with hypotension refractory to epinephrine, norepinephrine can be administered at 2-20 μg/kg/min, titrated to maintain adequate blood pressure 1
• In septic shock, early administration of norepinephrine (within 1-3 hours) may improve outcomes compared to delayed administration 5, 6