Norepinephrine is the first-line vasopressor in septic shock, with vasopressin commonly added if shock persists. Evidence suggests that early initiation of vasopressin may improve hemodynamic and clinical outcomes; however, data remain conflicting. This meta-analysis evaluates early vasopressin administration.

We searched PubMed, Embase, and Cochrane for studies comparing early vasopressin plus norepinephrine versus norepinephrine alone or later vasopressin initiation in septic shock. Outcomes included hospital and ICU length of stay (LOS), SOFA score, vasopressor duration, mortality (in-hospital and 28-day), arrhythmias, and renal replacement therapy (RRT). A random-effects model was used. Risk of bias was assessed using RoB2 and ROBINS-I tools.

Six studies ( n  = 1167 patients) met inclusion criteria, including two RCTs. Early vasopressin was associated with a significantly shorter hospital LOS (mean difference [MD] -4.48 days; 95 % CI -8.37 to −0.60; p  = 0.02; I ²  = 44 %). No significant differences were observed for ICU LOS (MD -0.73 days; p  = 0.42), vasopressor duration (MD -8.77 h; p  = 0.18), SOFA scores at 24 or 72 h, in-hospital mortality (OR 0.86; p  = 0.38), 28-day mortality (OR 0.84; p  = 0.20), arrhythmia risk (OR 0.99; p  = 0.98), or RRT use (OR 1.02; p  = 0.91). Risk of bias was high in most included studies, particularly among observational designs.

Early vasopressin may reduce hospital LOS in septic shock but does not improve mortality or other outcomes. Even though there is a possible benefit, current evidence does not support routine early use.