Clinical References

Pharmacology

vasopressor

Norepinephrine

Levophed

Route: IV (central line preferred; peripheral for short-term initiation)
Onset: 1–2 minutes
Duration: Minutes; constant infusion required

Mechanism of action

Endogenous catecholamine. Predominantly alpha-1 and alpha-2 agonist → peripheral vasoconstriction → increased MAP. Minimal beta-2 effects (no bronchodilation). Some beta-1 effects (inotropic) at high doses.

Dosing

Adult: 0.01–3 mcg/kg/min IV; titrate to MAP ≥65 mmHg. Start: 0.1–0.2 mcg/kg/min

Indications

Septic shock (first-line vasopressor per Surviving Sepsis Campaign)
Distributive shock (anaphylactic, neurogenic)
Hypotension refractory to fluids

Contraindications

Hypovolemia (must resuscitate first)
Mesenteric/peripheral vascular thrombosis
Pregnancy (reduces uterine blood flow)

Side effects

Hypertension
Reflex bradycardia
Peripheral ischemia / digital necrosis (high doses, prolonged)
Tissue necrosis with extravasation
Arrhythmias (rare at therapeutic doses)

Monitoring parameters

Blood pressure (continuous arterial line preferred)
Heart rate
Urine output
Peripheral perfusion / skin color
Lactate (clearance)
IV site for extravasation (use central line)

Drug interactions

MAOIs (severe hypertension)
TCAs (potentiated pressor response)
Beta-blockers (unopposed alpha → exaggerated hypertension)
Halothane (arrhythmias)

Norepinephrine (Levophed) — Respiratory Pharmacology