What is the recommended dosage of Levophed (norepinephrine) for treating hypotension in adults?

Norepinephrine Dosing for Hypotension in Adults

Norepinephrine should be initiated at 0.5-1 mL per minute (2-4 mcg/min of base) after diluting 4 mg in 1000 mL of 5% dextrose solution, titrated to achieve a mean arterial pressure (MAP) of 65 mmHg or higher. 1

Preparation and Initial Setup

• Dilute 4 mg (4 mL) of norepinephrine in 1000 mL of 5% dextrose solution to create a concentration of 4 mcg/mL 1
• Administer through a central venous line whenever possible to prevent tissue necrosis from extravasation 2
• If central access is unavailable, peripheral IV administration can be used temporarily with strict monitoring protocols 3
• Do not dilute in saline solution alone; dextrose-containing fluids protect against potency loss from oxidation 1

Initial Dosing Protocol

• Start with 2-3 mL per minute (8-12 mcg/min of base) and observe the initial response 1
• For weight-based dosing: initiate at 0.1-0.5 mcg/kg/min (equivalent to 7-35 mcg/min in a 70 kg adult) 3
• Titrate to achieve a target MAP of 65-100 mmHg sufficient to maintain vital organ perfusion 2
• In previously hypertensive patients, raise blood pressure no higher than 40 mmHg below the pre-existing systolic pressure 1

Maintenance Dosing

• Average maintenance dose ranges from 0.5-1 mL per minute (2-4 mcg/min of base) 1
• Alternative dosing framework: 0.2-1.0 mcg/kg/min for acute heart failure or cardiogenic shock 2
• Adjust dose every 4 hours as needed, increasing by 0.5 mg/h increments up to a maximum of 3 mg/h 3

High-Dose Considerations and Escalation

• Great individual variation exists in required doses; titrate according to patient response 1
• Doses as high as 68 mg base (17 vials) daily may occasionally be necessary if hypotension persists 1
• Doses exceeding 10 mcg/min are associated with increased mortality and should be avoided when possible 2
• Before escalating to high doses, always suspect and correct occult blood volume depletion using central venous pressure monitoring 1
• If blood pressure remains inadequate despite increasing doses, consider adding a second vasopressor (vasopressin 0.03 units/min or epinephrine) rather than continuing to escalate norepinephrine 4, 2

Critical Pre-Administration Requirements

• Correct volume depletion as fully as possible before administering any vasopressor 1
• Norepinephrine is relatively contraindicated in hypovolemic patients; vasoconstriction in this setting causes severe organ hypoperfusion despite "normal" blood pressure 2, 3
• When intraaortic pressures must be maintained emergently to prevent cerebral or coronary ischemia, norepinephrine can be administered before and concurrently with blood volume replacement 1
• Administer whole blood or plasma separately (using a Y-tube setup) if needed to increase blood volume 1

Monitoring Protocol

• Monitor blood pressure and heart rate every 5-15 minutes during initial titration 2, 3
• Use continuous hemodynamic monitoring throughout administration 2
• Place an arterial catheter as soon as practical in all patients requiring vasopressors 4
• Assess peripheral perfusion regularly (skin temperature, capillary refill, urine output) 3
• Monitor for signs of excessive vasoconstriction including cold extremities and decreased urine output 3

Extravasation Management

• Watch continuously for signs of extravasation during infusion 2
• If extravasation occurs, immediately infiltrate 5-10 mg of phentolamine diluted in 10-15 mL of saline into the affected site to prevent tissue necrosis 2, 3, 1
• Pediatric phentolamine dose: 0.1-0.2 mg/kg up to 10 mg 3

Weaning Protocol

• Reduce gradually, avoiding abrupt withdrawal 1
• Decrease by 25% of the current dose every 30 minutes as tolerated 2
• Continue infusion until adequate blood pressure and tissue perfusion are maintained without therapy 1
• Treatment duration varies; some cases of vascular collapse from acute myocardial infarction required up to 6 days 1

Special Clinical Considerations

• Use cautiously in patients with ischemic heart disease as norepinephrine increases myocardial oxygen requirements 2
• In septic shock, norepinephrine may paradoxically improve renal blood flow and urine output despite typically causing renal vasoconstriction 2
• For beta-blocker toxicity, norepinephrine is more effective than dopamine for treating hypotension 3
• Obese patients require lower weight-based doses (approximately 0.09 mcg/kg/min) but similar total doses compared to non-obese patients 5
• Do not mix with sodium bicarbonate or other alkaline solutions in the IV line, as norepinephrine is inactivated in alkaline solutions 3

Context Within Vasopressor Guidelines

The Surviving Sepsis Campaign strongly recommends norepinephrine as the first-choice vasopressor for septic shock over alternatives like dopamine or phenylephrine 4. This recommendation is based on moderate quality evidence showing superior outcomes with norepinephrine. Dopamine should only be used in highly selected patients with low risk of tachyarrhythmias and absolute or relative bradycardia 4.