1. Norepinephrine (Levophed) — FIRST-LINE for Septic Shock

Starting dose

• 0.01–0.05 mcg/kg/min

Typical range

• 0.05–1 mcg/kg/min
  (Common ICU range ~0.05–0.3)

Receptors

• α1 (+++)

• β1 (+)

Clinical Use

• First-line for septic shock

• Increases MAP via vasoconstriction

• Minimal HR increase

Pearls

• If dose > 0.1–0.2 mcg/kg/min → add vasopressin, don’t just escalate norepi indefinitely.

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2. Vasopressin — Add-On Pressor

Dose

• 0.03 units/min (fixed dose)

  • NOT weight-based

  • NOT titrated

Receptors

• V1 (vasoconstriction)

• No direct α or β activity

Clinical Use

• Adjunct when norepi is 0.1–0.2 mcg/kg/min

• Good for catecholamine-refractory shock

Pearls

• More effective in acidotic states

• Helps lower norepi requirement

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3. Epinephrine — Add-On or Second-Line

Starting dose

• 0.01–0.05 mcg/kg/min

Typical range

• 0.02–0.3 mcg/kg/min

Receptors

• β1 (++), β2 (++), α1 (+)

• At higher doses → more α1

Clinical Use

• Refractory septic shock

• Anaphylaxis (IV drip in ICU, IM for initial tx)

• Cardiogenic shock (if bradycardic)

Pearls

• Increases lactate (β2 effect) → don’t confuse with worsening shock

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4. Phenylephrine — Pure Alpha

Starting dose

• 0.1–0.5 mcg/kg/min

Typical range

• 0.5–3 mcg/kg/min

Receptors

• α1 only

Clinical Use

• Tachyarrhythmias (AFib RVR)

• Vasoplegia after anesthesia

• Avoid in cardiogenic shock

Pearls

• Pure vasoconstriction → may worsen cardiac output

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5. Dopamine — Rarely Used

Dose Ranges

• Low (1–5 mcg/kg/min): dopamine (renal) receptors

• Medium (5–10): β1

• High (10–20): α1

Receptors

• α, β, dopamine (dose-dependent)

Clinical Use

• Limited use — arrhythmias common

Pearls

• Avoid except for bradycardic shock when epinephrine unavailable

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6. Dobutamine — Inotrope (NOT a pressor)

Starting dose

• 2.5–5 mcg/kg/min

Typical range

• 5–20 mcg/kg/min

Receptors

• β1 (++), β2 (+)

Clinical Use

• Cardiogenic shock with low cardiac output

• Right heart failure

• Sepsis-induced cardiomyopathy

Pearls

• May decrease BP → use with norepi

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7. Milrinone — Inodilator

Dose

• 0.125–0.75 mcg/kg/min
  (Avoid bolus in shock)

Mechanism

• PDE-3 inhibitor

• Increases contractility

• Vasodilation

Use

• Right heart failure

• Post-cardiac surgery

• Low-output HF

Pearls

• Renal clearance → avoid in AKI

• Can worsen hypotension

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8. Angiotensin II (Giapreza)

Starting dose

• 20 ng/kg/min

Typical range

• 10–80 ng/kg/min

Receptor

• AT1 receptor

Use

• Refractory vasodilatory shock (after high-dose norepi + vaso)

Pearls

• Raises MAP fast