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.
- Evidence context
- Vasodilatory shock, septic shock vasopressor therapy, V1a/V2 receptor pharmacology research
- Evidence grade
- Level A
- Confidence
- High
- Reference context
- Regulatory label reference: 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.
Quick Answers
Where is the strongest evidence for Vasopressin?
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. Evidence context: Vasodilatory shock, septic shock vasopressor therapy, V1a/V2 receptor pharmacology research.
What are the main side effects of Vasopressin?
Vasopressin side effects and warning signals include Hyponatremia (with excessive doses), Peripheral vasoconstriction and digital ischemia, Abdominal cramping, Nausea, and Chest pain.
What evidence level is Vasopressin?
Vasopressin is rated Level A; the listed research status is FDA Approved.