Vasopressin Evidence Guide
Vasopressin (Vasostrict) is FDA-approved for vasodilatory shock (septic shock, post-cardiotomy vasodilatory shock) with Phase 3 evidence from the VASST trial showing non-inferiority to norepinephrine and steroid-sparing potential in septic shock. As an endogenous hormone with a distinct vasoconstrictive mechanism, it is a standard vasopressor in critical care medicine.
Our Take
Vasopressin (Vasostrict) is FDA-approved for vasodilatory shock (septic shock, post-cardiotomy vasodilatory shock) with Phase 3 evidence from the VASST trial showing non-inferiority to norepinephrine and steroid-sparing potential in septic shock. As an endogenous hormone with a distinct vasoconstrictive mechanism, it is a standard vasopressor in critical care medicine.
- Best for
- Vasodilatory shock, septic shock vasopressor therapy, V1a/V2 receptor pharmacology research
- Evidence grade
- Level A
- Confidence
- High
- Starting point
- 0.03-0.04 units/minute IV infusion (shock dosing; not titrated like catecholamines)
Benefits and Evidence
- Vasodilatory Shock Treatment: Level A, includes human evidence - Russell et al. (2008, N Engl J Med, VASST trial, n=778) showed low-dose vasopressin (0.01-0.03 U/min) combined with norepinephrine did not reduce 28-day mortality overall vs. norepinephrine alone, but a pre-specified subgroup with less severe shock (NE 5-14 ug/min) had lower mortality (26.5% vs. 35.7%, p=0.05); Gordon et al. (2016, VANISH trial, n=409) confirmed vasopressin reduced renal failure incidence.
- Diabetes Insipidus Management: Level A, includes human evidence - Effectively controls polyuria and polydipsia in central diabetes insipidus by replacing deficient endogenous vasopressin. Gold standard for acute management.
- Cardiac Arrest Adjunct: Level B, includes human evidence - Used as alternative or adjunct to epinephrine in cardiac arrest algorithms. Some evidence of benefit in asystolic arrest, though overall evidence for improved outcomes is mixed.
Side Effects and Warnings
- Hyponatremia (with excessive doses)
- Peripheral vasoconstriction and digital ischemia
- Abdominal cramping
- Nausea
- Chest pain
- Arrhythmias
- Water intoxication/hyponatremia risk with excessive doses
- Digital and mesenteric ischemia - monitor extremities
Research Dosage References
- <strong>Intravenous infusion</strong> - 0.01-0.04 units/min - Continuous (for vasodilatory shock) - Vasostrict. Do not exceed 0.07 units/min. Titrate to target MAP. Used as adjunct to catecholamine vasopressors.
- <strong>Intramuscular/Subcutaneous</strong> - 5-10 units - Every 4-6 hours as needed - For diabetes insipidus. Titrate based on urine output and serum sodium. Desmopressin generally preferred for chronic management.
- <strong>Intravenous bolus</strong> - 40 units - Single dose (in cardiac arrest) - ACLS protocol. May replace first or second dose of epinephrine in cardiac arrest. Single dose only.
Mechanism of Action
Vasopressin acts through multiple receptor subtypes: 1. V1a receptor activation: Causes vascular smooth muscle contraction and vasoconstriction, increasing systemic vascular resistance and blood pressure. Mechanism is independent of adrenergic receptors. 2. V2 receptor activation: Stimulates insertion of aquaporin-2 water channels in renal collecting duct cells, increasing water reabsorption and concentrating urine. 3. V1b receptor activation: Stimulates ACTH release from anterior pituitary corticotrophs, contributing to stress hormone response. 4. Non-adrenergic vasopression: In vasodilatory shock, provides vasoconstriction through a catecholamine-independent mechanism, making it effective even when patients are refractory to catecholamine vasopressors.
Legal Status
FDA-approved for vasodilatory shock (Vasostrict), diabetes insipidus, and prevention/treatment of postoperative abdominal distension. Available by prescription. Multiple manufacturers.
Primary Sources
- Vasopressin versus norepinephrine infusion in patients with septic shock (VASST). N Engl J Med, 2008.
- Vasopressin in hemorrhagic shock: a systematic review and meta-analysis. Resuscitation, 2015.
- A randomized clinical trial of vasopressin and epinephrine for in-hospital cardiac arrest. Resuscitation, 2012.