Episode Details

Norepinephrine (Levophed) 80/20 Summary

• Action & MOA: Direct α-agonist causing potent vasoconstriction. Modest β1​ activity triggers cardiac stimulation at lower doses; vasoconstriction dominates at higher doses. Elevated SVR triggers reflex vagal bradycardia (slowing HR). Coronary flow increases without raising myocardial oxygen demand.
• Uses: First-line for septic shock, sepsis, acute hypotension, cardiogenic shock. Alternative in hepatorenal syndrome (with albumin).
• Complications: Tissue necrosis (extravasation), bradycardia, lactic acidosis, pulmonary edema, hypertension, and local hypoxia.
• Administration & Dilution:
  • Dilution: Standard: 4mg in 1,000mL. Preferred: D5W/D5NS (dextrose protects against oxidation). Saline alone stable up to 16mcg/mL, though FDA discourages. Adult standard: 16, 32, 128mcg/mL.
  • Incompatibility: Do not mix with alkaline solutions (e.g., bicarb). Reject if pinkish/discolored or has precipitate.
  • Route: Large vein infusion; transition to central line ASAP. Avoid leg veins in elderly.
  • Monitoring: BP every 2 mins initially, then every 5 mins. Check site frequently for free flow/extravasation.
  • Weaning: Reduce rate gradually; avoid abrupt withdrawal to prevent rebound hypotension.
• Extravasation Antidote: Infiltrate ASAP (within 12h) with phentolamine 5-10mg in 10-15mL NS.
• Pharmacokinetics: Onset <30s; steady-state 5 mins; duration <10 mins. Half-life ~2.4 mins; metabolized by COMT/MAO.
• Why Choose It? Preferred in septic shock; raises MAP/SVR with less tachycardia than dopamine, sparing oxygen demand.

Final 80/20 Review

• The 20% to Absolutely Know:
  1. Hypovolemia First: Correct fluid deficit before starting norepinephrine.
  2. Central Line Priority: Transition to central line ASAP to mitigate necrosis risk.
  3. Phentolamine for Extravasation: Immediate local infiltration reverses ischemia.
  4. Dextrose Over Saline: Dextrose-containing diluents prevent oxidation.
  5. Incompatible with Bicarb: Inactivated in alkaline solutions.
• If I Remember Nothing Else: Norepinephrine is the first-line vasopressor for septic shock. With a <30s onset and 2.4m half-life, it requires continuous infusion, BP checks every 2–5 mins, and gradual weaning. Monitor the IV site continuously; treat extravasation with immediate phentolamine infiltration to prevent necrosis.