What is the preferred vasopressor, dopamine or noradrenaline (norepinephrine), for a patient in septic shock?

Norepinephrine Over Dopamine for Septic Shock

Norepinephrine is the mandatory first-line vasopressor for septic shock, while dopamine should only be used in highly selected patients with low risk of tachyarrhythmias or absolute/relative bradycardia. 1, 2

Evidence-Based Rationale

The Surviving Sepsis Campaign gives norepinephrine a Grade 1B (strong) recommendation based on compelling mortality data 1:

• Norepinephrine reduces 28-day mortality by 11% absolute risk reduction compared to dopamine (RR 0.91; 95% CI 0.83-0.99), translating to a number needed to treat of 9 patients 1
• Meta-analysis of 1,698 patients confirms norepinephrine's survival advantage over dopamine (RR 0.89; 95% CI 0.81-0.98) 3
• Network meta-analysis ranking vasopressors from most to least effective places dopamine near the bottom, associated with higher 28-day mortality risk than norepinephrine, terlipressin, and vasopressin 4

Safety Profile Strongly Favors Norepinephrine

Dopamine carries significantly higher risks of serious adverse events 1, 3:

• Supraventricular arrhythmias: 53% risk reduction with norepinephrine (RR 0.47; 95% CI 0.38-0.58) 1
• Ventricular arrhythmias: 65% risk reduction with norepinephrine (RR 0.35; 95% CI 0.19-0.66) 1
• Dopamine is associated with the highest incidence of cardiac arrhythmias among all vasopressors 4

Hemodynamic Considerations

The physiologic differences explain the clinical outcomes 1:

• Norepinephrine increases MAP primarily through alpha-adrenergic vasoconstriction with minimal heart rate increase and modest beta-1 cardiac stimulation, maintaining cardiac output while raising systemic vascular resistance 1, 2
• Dopamine increases MAP and cardiac output through increased stroke volume and heart rate, but this tachycardic effect increases myocardial oxygen demand and arrhythmia risk 1

Practical Implementation Algorithm

Initial Management

• Administer minimum 30 mL/kg crystalloid in first 3 hours before or concurrent with vasopressor initiation 2, 5
• Start norepinephrine immediately if life-threatening hypotension persists after fluid resuscitation 2, 5
• Target MAP ≥65 mmHg initially (consider 70-75 mmHg in chronic hypertension) 2, 5
• Establish central venous access for safe administration and arterial catheter for continuous blood pressure monitoring 2, 6

Escalation Strategy for Refractory Hypotension

If target MAP not achieved with norepinephrine alone 2, 5:

1. Add vasopressin 0.03 units/minute (maximum 0.03-0.04 units/minute for routine use)
2. Add epinephrine 0.05-2 mcg/kg/min if MAP target still not met
3. Add dobutamine 2.5-20 mcg/kg/min if persistent hypoperfusion despite adequate MAP, particularly with myocardial dysfunction
4. Consider hydrocortisone 200 mg/day IV for refractory shock

The Narrow Exception for Dopamine

Dopamine receives only a Grade 2C (weak) recommendation as an alternative to norepinephrine, and only in highly selected patients 1, 2:

• Patients with absolute or relative bradycardia where increased heart rate would be beneficial
• Patients with low risk of tachyarrhythmias (no history of arrhythmias, no structural heart disease, no electrolyte abnormalities)

Even in these scenarios, the mortality and arrhythmia data suggest norepinephrine remains safer.

Critical Pitfalls to Avoid

• Never use dopamine for renal protection—this is strongly discouraged and has no benefit 2
• Do not delay norepinephrine while pursuing aggressive fluid resuscitation in severe hypotension; early vasopressor use as emergency measure is appropriate when diastolic blood pressure is critically low 1
• Avoid escalating norepinephrine beyond 15 mcg/min without adding second-line agents (vasopressin or epinephrine), as high-dose norepinephrine is associated with increased mortality 2
• Monitor tissue perfusion continuously, not just MAP—assess lactate clearance, urine output ≥0.5 mL/kg/hr, mental status, capillary refill, and skin temperature 2, 5