What are the recommended doses and infusion rates (in mL per hour and µg per kilogram per minute) for common vasopressors in adult patients?

Vasopressor Dosing and Infusion Rates

Norepinephrine is the first-line vasopressor, typically started at 0.05-0.1 µg/kg/min (approximately 5-10 µg/min or 3-6 mL/hr for a standard 16 µg/mL concentration in a 70 kg patient), with vasopressin added at a fixed dose of 0.03 units/min (1.8 units/hr) when additional support is needed. 1, 2

First-Line Agent: Norepinephrine

Starting and Titration Doses

• Initial dose: 0.05-0.1 µg/kg/min (typically 5-10 µg/min for average adult)
• Standard concentration: 16 µg/mL (4 mg in 250 mL)
  • For 70 kg patient: 3-6 mL/hr starting rate
  • For 80 kg patient: 4-7 mL/hr starting rate
• Target: Mean arterial pressure (MAP) ≥65 mmHg 1, 2
• Maximum effective dose: Data suggests mortality risk substantially increases above 0.5 µg/kg/min 3. The 90th percentile of maximum dosing in clinical practice is 0.5 µg/kg/min for norepinephrine 4
  • For 70 kg patient at 0.5 µg/kg/min: approximately 30 mL/hr (using 16 µg/mL concentration)

Critical Dosing Threshold

When norepinephrine reaches moderate doses (typically 0.25-0.5 µg/kg/min or 15-30 mL/hr for standard concentration), add vasopressin rather than continuing to escalate norepinephrine alone 1, 2. This approach minimizes catecholamine-related complications including arrhythmias and tissue ischemia.

Second-Line Agent: Vasopressin

Fixed Dosing

• Dose: 0.03 units/min (1.8 units/hr) - this is a fixed dose, not weight-based 1, 2
• Standard concentration: 20 units in 100 mL (0.2 units/mL)
  • Infusion rate: 9 mL/hr for 0.03 units/min
• Do NOT titrate - vasopressin is used at this single fixed dose 2, 5
• Do NOT use as sole initial vasopressor 2

The evidence shows no hemodynamic benefit from using 0.04 units/min compared to 0.03 units/min 6, and guidelines explicitly recommend the lower dose 1, 2. While vasopressin did not reduce overall mortality compared to norepinephrine alone 7, it effectively reduces norepinephrine requirements and may benefit patients with less severe shock.

Alternative Agents (Highly Selected Situations)

Epinephrine

• Dose range: 0.05-0.5 µg/kg/min
• Standard concentration: 8 µg/mL (2 mg in 250 mL)
  • For 70 kg patient: 3-30 mL/hr range
• Use: Added to or substituted for norepinephrine when additional agent needed 1, 2
• Maximum with reasonable survival: 0.5 µg/kg/min; mortality approaches 100% above 9.6 µg/kg/min 3

Dopamine

• Dose range: 5-20 µg/kg/min (vasopressor effects typically >10 µg/kg/min)
• Standard concentration: 1600 µg/mL (400 mg in 250 mL)
  • For 70 kg patient: 13-53 mL/hr range
• Use ONLY in: Patients with low risk of tachyarrhythmias AND absolute or relative bradycardia 1, 2
• Do NOT use low-dose dopamine for renal protection - this is explicitly contraindicated 1, 2
• 90th percentile maximum: 15 µg/kg/min 4

Phenylephrine

• Dose range: 0.5-3 µg/kg/min (approximately 40-200 µg/min)
• Standard concentration: 400 µg/mL (100 mg in 250 mL)
  • For 70 kg patient: 6-30 mL/hr range
• Use ONLY when: (a) norepinephrine causes serious arrhythmias, (b) cardiac output is high with persistently low BP, or (c) salvage therapy when other agents fail 2
• 90th percentile maximum: 316.5 µg/min 4

Inotropic Support: Dobutamine

• Dose range: 2.5-20 µg/kg/min
• Standard concentration: 1000 µg/mL (250 mg in 250 mL)
  • For 70 kg patient: 10-84 mL/hr range
• Indication: Persistent hypoperfusion despite adequate fluid loading and vasopressor use 1, 2
• Titrate to perfusion endpoints; reduce or discontinue if worsening hypotension or arrhythmias occur 1

Practical Infusion Considerations

Administration Route

Peripheral administration of vasopressors is increasingly recognized as safe for initial stabilization, particularly when using large-bore catheters in proximal upper extremity veins with vigilant monitoring 8, 9. However, place an arterial catheter as soon as practical for all patients requiring vasopressors 1, 2.

Key Safety Points

• Extravasation risk: Monitor infusion sites closely; have phentolamine available for extravasation management
• Early initiation: Do not delay vasopressor initiation waiting for central access 10, 11
• Transition to central access: Plan for CVC placement if prolonged infusion anticipated (>6-12 hours)

Clinical Algorithm

1. Start norepinephrine at 0.05-0.1 µg/kg/min peripherally if needed
2. Titrate norepinephrine to MAP ≥65 mmHg
3. At 0.25-0.5 µg/kg/min norepinephrine, add vasopressin 0.03 units/min (fixed dose)
4. If still inadequate, add epinephrine 0.05-0.5 µg/kg/min
5. Consider dobutamine if signs of persistent hypoperfusion despite adequate MAP

Mortality Considerations

The 90th percentile of maximum combined vasopressor dose (norepinephrine-equivalents) is 0.7 µg/kg/min across all agents 4. While survival decreases substantially above 0.5 µg/kg/min of norepinephrine or epinephrine 3, some patients survive even with higher doses 4, so there is no absolute cutoff mandating withdrawal of care based solely on vasopressor requirements.