Vasopressor weaning in septic shock: Why the field has been asking the wrong question.

The optimal sequence for weaning norepinephrine and vasopressin in recovering septic shock patients remains unresolved despite thirteen comparative studies enrolling over 2500 patients. A striking paradox defines this literature: both available randomized trials suggest weaning norepinephrine first produces more hypotension, while the observational evidence consistently suggests the opposite. We argue this contradiction is methodological rather than biological, arising from three interacting confounds no study has adequately addressed: hypotension definitions that conflate clinician dose-escalation behavior with patient hemodynamic events; failure to distinguish weaning sequence from the method of vasopressin withdrawal (abrupt versus titrated); and uncontrolled corticosteroid use that modifies vasopressor pharmacology through the V3-ACTH-cortisol axis. We propose a pharmacological framework built on the distinct half-lives, receptor biology, and hemodynamic roles of norepinephrine and vasopressin that suggests specific predictions about which patients may be at greatest risk from each withdrawal approach. We also identify a subgroup, patients with reduced left ventricular function, where directional evidence from two independent datasets suggests potential benefit with vasopressin-first weaning, though prospective validation is required. We propose a 2 × 2 factorial trial addressing sequence and method simultaneously, and note that the recently registered WAVES trial (NCT07067866) will provide complementary evidence on withdrawal method that would strengthen the rationale for such a design.