Adjunctive Terlipressin in Refractory Septic Shock: Lowers High-Dose Catecholamine Need at 6 Hours but No Mortality Benefit

Highlights

– In a single-center, double-blind RCT of refractory septic shock (n = 130), adjunctive terlipressin increased the proportion of patients who achieved MAP ≥65 mmHg with total catecholamine equivalent dose <0.2 mcg/kg/min at 6 hours (22.7% vs 9.4%; P = 0.039).

– There was no statistically significant difference in 28-day mortality (60.6% terlipressin vs 64.1% placebo; P = 0.68).

– Digital ischemia rates were similar and relatively high in both arms (≈28%), underscoring safety concerns with potent vasoconstrictors.

Background

Septic shock remains a leading cause of death in the intensive care unit. Current guideline-recommended first-line vasopressor therapy is norepinephrine. In patients with refractory shock who require escalating catecholamine support, adding non-catecholamine vasopressors (for example vasopressin or its analogues) is a common strategy to restore arterial pressure, reduce catecholamine exposure, and potentially limit catecholamine-related harms.

Terlipressin is a synthetic vasopressin analogue with strong V1 receptor activity and a longer half-life than native vasopressin. It causes arteriolar vasoconstriction and can raise mean arterial pressure (MAP) and reduce catecholamine requirements. However, concerns persist about regional ischemia (digital, mesenteric, myocardial) and unclear impacts on patient-centered outcomes such as mortality.

Study design

Investigators conducted a single-center, prospective, double-blind, randomized, placebo-controlled trial in a medical intensive care unit. Adults with septic shock who required high-dose catecholamines (norepinephrine > 0.2 mcg/kg/min or use of epinephrine) were randomized 1:1 to receive adjunctive terlipressin or placebo. The trial enrolled 130 patients (66 terlipressin, 64 placebo). Baseline characteristics and severity appeared balanced; median baseline norepinephrine-equivalent dose was 0.39 mcg/kg/min in each arm.

The prespecified primary outcome was the proportion of patients who achieved mean arterial pressure ≥65 mmHg with a total catecholamine-equivalent dose below 0.2 mcg/kg/min at 6 hours after randomization.

Key findings and interpretation

Primary outcome. More patients in the terlipressin group met the primary outcome at 6 hours: 22.7% versus 9.4% in the placebo group (reported relative risk [RR] = 1.53, 95% CI 1.09–2.14; P = 0.039). This represents an absolute difference of approximately 13.3 percentage points, corresponding to a number needed to treat (NNT) of roughly 8 to achieve this hemodynamic/catecholamine endpoint.

Clinical interpretation: adjunctive terlipressin increased the probability of early hemodynamic stabilization defined by MAP and reduced catecholamine exposure. Reducing catecholamine dose is conceptually appealing because high catecholamine exposure is associated with adverse effects (arrhythmia, metabolic disturbances, immunomodulation), but whether short-term reductions translate into improved patient-centered outcomes is uncertain.

Mortality and patient-centered outcomes. The 28-day mortality was high in both groups and did not differ significantly: 60.6% (terlipressin) versus 64.1% (placebo) (RR = 0.93, 95% CI = 0.66–1.31; P = 0.68). There was no evidence from this trial that terlipressin reduced mortality.

Clinical interpretation: despite a favorable effect on a short-term hemodynamic surrogate, terlipressin did not alter 28-day survival in this cohort. The trial was relatively small and likely underpowered for mortality, which remained high overall. The degree to which early reductions in catecholamine need translate to improved survival, organ support duration, or functional outcomes remains unproven.

Safety signals. Digital ischemia occurred in 28.8% of patients in the terlipressin group and 27.4% in the placebo group (P = 0.86). These rates are notable and higher than typically reported for many vasopressors, though the trial population had severe shock and high vasopressor exposures at baseline.

Clinical interpretation: terlipressin is a potent vasoconstrictor and raises legitimate concerns about regional ischemia. In this trial, digital ischemia rates were similar between groups—possibly reflecting high background rates in refractory shock—but vigilance for ischemic complications is essential when using V1 agonists. Detailed data on other ischemic endpoints (e.g., mesenteric ischemia, limb necrosis requiring surgery, myocardial ischemia) were not presented in the summary and should be reviewed in the full report.

Statistics and reporting notes. The summary reports an RR = 1.53 for the primary outcome with a 95% CI 1.09–2.14, despite raw proportions (22.7% vs 9.4%) yielding an unadjusted ratio nearer to 2.4. This discrepancy may reflect an adjusted analysis (for baseline covariates), a presentation convention, or a transcription issue in the abstract. Readers should consult the full text to confirm the analytic methods used to derive the reported RR.

Context with prior evidence

Previous large trials have evaluated vasopressin (native hormone) as an adjunctive vasopressor in septic shock. The VASST trial (Russell et al., NEJM 2008) found no overall mortality benefit for vasopressin added to norepinephrine, though a subgroup with less severe shock appeared to derive benefit. SOAP II (De Backer et al., NEJM 2010) compared norepinephrine to dopamine and favored norepinephrine for fewer arrhythmias and better outcomes. Surviving Sepsis Campaign guidelines recommend norepinephrine as first-line and suggest vasopressin (fixed dose) as an adjunct to raise MAP or reduce norepinephrine requirements, without strong evidence for mortality reduction.

Terlipressin differs pharmacodynamically from vasopressin (longer-acting V1 agonist) and has shown promise in small, physiologic studies to increase MAP and reduce catecholamine need. However, robust, multicenter trials powered for clinical outcomes have been lacking until recent data such as the current trial.

Expert commentary and limitations

Strengths of this trial include randomization, double-blinding, and enrollment of a critically ill population with clearly defined refractory shock. The primary outcome was objective and clinically relevant as a hemodynamic and catecholamine-sparing endpoint.

Key limitations include single-center conduct, modest sample size, and selection of an early physiologic surrogate as the primary endpoint rather than a patient-centered outcome such as mortality, ventilator-free days, renal replacement–free days, or functional status. The trial’s high baseline vasopressor doses and high mortality may limit generalizability to other settings where shock severity differs. The unexpectedly high rates of digital ischemia in both arms merit careful scrutiny and additional reporting details (severity, need for intervention, reversibility).

Open questions include the optimal dosing strategy for terlipressin (bolus vs infusion, fixed vs weight-based), how to identify patients most likely to benefit (biomarkers, hemodynamic phenotypes, catecholamine dependency), and the safety trade-offs in terms of ischemic complications. Mechanistically, terlipressin’s vasoconstrictive potency could preserve central perfusion pressure while worsening regional perfusion; monitoring strategies and dose titration algorithms need development.

Clinical implications

For clinicians managing refractory septic shock, this trial suggests that terlipressin can be effective at achieving early hemodynamic goals and reducing catecholamine exposure. However, because there was no demonstrated mortality benefit and because ischemia risk remains a concern, terlipressin should be considered a rescue adjunct in carefully selected patients rather than routine therapy. When used, clinicians should monitor for ischemic complications, reassess peripheral perfusion frequently, and consider rapid dose de-escalation when MAP targets are achieved.

Conclusion

This randomized, placebo-controlled trial indicates that adjunctive terlipressin increases the likelihood of achieving MAP ≥65 mmHg with reduced catecholamine dosing at 6 hours among patients with refractory septic shock, but it did not reduce 28-day mortality. The similar and substantial rates of digital ischemia in both groups highlight safety concerns and the need for detailed adverse-event reporting. Larger, multicenter trials that are adequately powered for patient-centered outcomes and that clarify optimal dosing, patient selection, and safety monitoring are needed before terlipressin can be broadly recommended for refractory septic shock.

Funding and ClinicalTrials.gov

Trial registration: ClinicalTrials.gov NCT04339868 (registered April 7, 2020). Funding details were not included in the summary provided here; readers should consult the full published article for funding sources, conflict-of-interest statements, and protocol details.

References

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3. De Backer D, Biston P, Devriendt J, et al.; SOAP II Investigators. Comparison of dopamine and norepinephrine in the treatment of shock. N Engl J Med. 2010 Sep 30;362(9):779-789. doi:10.1056/NEJMoa0907118.

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