What is the protocol for tapering noradrenaline (norepinephrine) and when to add vasopressin in a patient with hypotension?

Norepinephrine Tapering and Vasopressin Addition Protocol

Add vasopressin at 0.03 units/minute when norepinephrine alone fails to maintain a MAP of 65 mmHg despite adequate fluid resuscitation, then taper norepinephrine gradually while maintaining hemodynamic stability. 1

When to Add Vasopressin

Initiate vasopressin when norepinephrine requirements remain elevated or when you need to decrease norepinephrine dosage to achieve target MAP. 1 The Society of Critical Care Medicine specifically recommends adding vasopressin to norepinephrine (rather than escalating norepinephrine alone) when the target MAP cannot be achieved with initial vasopressor therapy. 1

Key Vasopressin Dosing Parameters:

• Standard dose: 0.03 units/minute (range 0.01-0.03 units/minute) 1, 2
• Never use vasopressin as monotherapy—it must always be added to norepinephrine 1, 2
• Do not exceed 0.03-0.04 units/minute except as salvage therapy when other vasopressors have failed 1
• Alternative dosing from trauma literature: bolus of 4 IU followed by 0.04 IU/min has shown benefit in hemorrhagic shock 3

Norepinephrine Tapering Protocol

Initial Setup Requirements:

• Ensure central venous access for safe administration 1, 4
• Place arterial catheter for continuous blood pressure monitoring as soon as practical 1, 4
• Target MAP ≥65 mmHg in most patients 1, 2, 4

Tapering Strategy After Vasopressin Addition:

Once vasopressin is added at 0.03 units/minute, you can either raise MAP to target OR decrease norepinephrine dosage while maintaining hemodynamic stability. 1 While specific tapering increments are not rigidly defined in guidelines, gradual dose reduction is preferred over abrupt discontinuation. 1

Critical Evidence on Discontinuation Order:

When weaning dual vasopressor therapy, discontinue norepinephrine FIRST, not vasopressin. 5 A retrospective cohort study demonstrated that discontinuing vasopressin before norepinephrine resulted in a 56% incidence of hypotension within 24 hours, compared to only 16% when norepinephrine was discontinued first (adjusted relative risk 5.9,95% CI 1.7-21.0, P=0.006). 5 This represents a critical clinical pitfall that significantly impacts patient outcomes.

Monitoring During Tapering:

• Monitor blood pressure and heart rate every 5-15 minutes during initial titration 4
• Assess perfusion markers beyond just MAP: capillary refill, urine output, lactate clearance, mental status 4
• Watch for signs of excessive vasoconstriction: cold extremities, decreased urine output, rising lactate 1

Alternative Escalation Strategies

If hemodynamic targets remain unmet despite norepinephrine plus vasopressin:

• Add epinephrine as a third agent rather than increasing vasopressin beyond 0.03-0.04 units/minute 1
• Consider dobutamine (up to 20 mcg/kg/min) for persistent hypoperfusion despite adequate vasopressor support, particularly with evidence of myocardial dysfunction 3, 1, 2

Common Pitfalls to Avoid

What NOT to Do:

• Never use dopamine for renal protection—this is strongly discouraged and has no benefit 1, 2
• Avoid dopamine as first-line therapy—it is associated with higher mortality and more arrhythmias compared to norepinephrine, and should only be used in highly selected patients with low risk of tachyarrhythmias or absolute/relative bradycardia 1, 2
• Do not use phenylephrine except in specific circumstances: norepinephrine-induced serious arrhythmias, high cardiac output with persistent hypotension, or salvage therapy 1, 2
• Do not discontinue vasopressin before norepinephrine when weaning dual therapy—this increases hypotension risk nearly 6-fold 5
• Do not delay norepinephrine initiation waiting to complete entire fluid resuscitation if life-threatening hypotension (systolic BP <80 mmHg) is present 3, 2

Fluid Resuscitation Context:

Adequate fluid resuscitation (minimum 30 mL/kg of crystalloids) should precede or accompany vasopressor therapy. 1 In trauma patients with hemorrhagic shock, if restricted volume replacement and permissive hypotension (target systolic BP 80-90 mmHg) fail to achieve target blood pressure and severe hypotension with systolic BP <80 mmHg occurs, transient noradrenaline is recommended. 3