When to Stop Vasopressin in Shock
Discontinue vasopressin after norepinephrine has been weaned to low doses (typically < 0.1-0.15 µg/kg/min) and hemodynamic stability is achieved, as withdrawing vasopressin first is associated with significantly higher rates of rebound hypotension.
Discontinuation Strategy
Sequence of Withdrawal
The evidence strongly supports a specific order for vasopressor discontinuation:
- Wean norepinephrine first to low doses while maintaining vasopressin at 0.03 U/min 1
- Discontinue vasopressin last after norepinephrine has been substantially reduced
- This approach is based on the observation that withdrawing vasopressin first causes more hemodynamic instability 1
Multiple meta-analyses confirm this strategy reduces hypotension risk. When vasopressin is discontinued first, the incidence of clinically significant hypotension is dramatically higher (54-68% vs 32-11%) compared to discontinuing norepinephrine first 2, 3, 4. The odds ratio for hypotension when discontinuing vasopressin first is 13.8 (95% CI: 3.4-56.3) 4.
Timing Considerations
Begin weaning when:
- Mean arterial pressure (MAP) is stable at ≥65 mmHg for several hours
- Lactate is clearing or normalized
- Adequate tissue perfusion is restored (urine output, mental status, skin perfusion)
- Fluid resuscitation is complete
- The underlying septic process is controlled
Specific thresholds for discontinuation:
- Reduce norepinephrine dose progressively while monitoring MAP
- Once norepinephrine is at low doses (< 0.1-0.15 µg/kg/min), consider stopping it entirely
- After norepinephrine is discontinued and MAP remains stable for 1-2 hours, then wean vasopressin
- Taper vasopressin gradually (e.g., from 0.03 to 0.02 to 0.01 U/min) rather than abruptly 5
Monitoring During Weaning
Critical parameters to track:
- Continuous arterial blood pressure monitoring is essential 6
- Reassess MAP every 15-30 minutes during active weaning
- Monitor for hypotension within the first 6 hours after discontinuation, as this is when rebound occurs 7
- Track lactate levels and mixed/central venous oxygen saturation
- Assess urine output and clinical perfusion markers
The pressor effect of vasopressin fades within 20 minutes of stopping the infusion 8, making close monitoring in this immediate period crucial.
Important Caveats
When Vasopressin May Be Discontinued Earlier
Recent data suggests the discontinuation order may be less critical than previously thought in certain contexts:
- A 2025 study found no difference in hypotension within 6 hours regardless of discontinuation order 7
- In patients with left ventricular dysfunction (EF ≤40%), discontinuation order did not significantly impact hypotension rates (76% vs 81%) 9
However, these findings should be interpreted cautiously given the weight of evidence supporting norepinephrine-first discontinuation.
Computerized Weaning
Consider using computerized-assisted weaning protocols when available, as they may reduce unnecessary exposure to vasoactive drugs 1.
Risk of Re-escalation
Clinicians often maintain higher blood pressures than necessary due to overestimating re-aggravation risk 1. Be prepared to:
- Reinitiate vasopressors if MAP drops below 60 mmHg
- Administer fluid boluses (≥500 mL crystalloid rapidly) if hypotension occurs
- Have vasopressin immediately available for 24-48 hours after discontinuation
Clinical Outcomes
Importantly: While discontinuation order affects hypotension rates, it does not impact mortality, ICU length of stay, or hospital length of stay 2, 3, 4. The primary concern is avoiding hemodynamic instability during the recovery phase, not survival outcomes.
The goal is smooth hemodynamic transition off vasopressor support while minimizing the risk of requiring re-escalation of therapy.