Vasopressin (Vasostrict®)

• Core dose: Shock: 0.03–0.04 units/min IV fixed-dose (not titrated); Cardiac arrest: 40 units IV push (replaces first or second epinephrine dose)
• Onset/duration: IV onset immediate; half-life 10–20 min; pressor effect lasts 30–60 min after stopping
• Key danger: Tissue ischemia (splanchnic, coronary, digital); hyponatremia with prolonged use; arrhythmias; avoid bolus dosing outside cardiac arrest
• Special: Catecholamine-sparing vasopressor; works via V1 receptors independent of adrenergic system; useful when catecholamine-resistant or as adjunct to norepinephrine

• Generic Name: Vasopressin injection, USP (arginine vasopressin)
• Brand Names: Vasostrict® (premix and concentrated vials)
• Also Known As: Arginine vasopressin (AVP)

Non-catecholamine vasopressor (endogenous pituitary peptide); V1a/V1b/V2 receptor agonist

Mechanism of Action:

• V1a receptor activation → Gq/PLC-IP3-Ca²⁺-mediated vascular smooth-muscle contraction (systemic vasoconstriction)
• V2 receptor activation in renal collecting duct → aquaporin-2 insertion and free-water reabsorption (antidiuresis)
• V1b (V3) in pituitary → ACTH release
• In septic vasoplegia, vasopressin may restore catecholamine responsiveness and counteract NO-mediated vasodilation
• Typically used as fixed-dose adjunct to norepinephrine

Pharmacokinetics:

• Onset: Within minutes (reported 30–60 min for peak pressor effect)
• Half-life: ~10–20 minutes
• Distribution: Vd ~0.14–0.2 L/kg
• Metabolism: Rapidly cleared by hepatic/renal metabolism
• Elimination: Small fraction renally excreted unchanged

• Vasodilatory shock refractory to fluids and catecholamines — adjunct to norepinephrine in septic shock
• Post-cardiotomy vasoplegia (ICU/OR)
• Selected GI variceal hemorrhage protocols (usually when octreotide/terlipressin unavailable) with concurrent nitroglycerin (institutional)

• Septic shock (catecholamine-refractory)
• Vasodilatory shock
• Post-cardiotomy vasoplegia
• GI variceal hemorrhage (select protocols)

Available Forms (FDA-labeled):

• 20 units/mL vials (single-dose 1 mL; multi-dose 10 mL with preservative)
• Premix: 40 units/100 mL (0.4 U/mL) ready-to-use
• Premix: 60 units/100 mL (0.6 U/mL) ready-to-use

Adult Dosing - Septic Shock:

• Standard fixed dose: 0.03 U/min adjunct to norepinephrine
• Titration range (some protocols): 0.01–0.06–0.07 U/min
• Maximum: Avoid exceeding 0.06–0.07 U/min due to ischemia risk

Adult Dosing - Post-Cardiotomy Vasoplegia:

• Range: 0.03–0.1 U/min
• Careful titration to the lowest effective dose

Pediatric Dosing (Catecholamine-Refractory Septic Shock):

• Typical range: 0.0003–0.002 U/kg/min (0.3–2 mU/kg/min)
• Neonatal ICU: May start as low as 0.0001 U/kg/min and titrate by 0.0002–0.0003 U/kg/min to effect
• Use only in PICU/NICU settings with invasive monitoring

Administration:

• Run on a smart pump with dose in units/min (adults) or units/kg/min (pediatrics)
• Dedicated lumen preferred
• Peripheral start is acceptable while securing central access when shock is life-threatening
• Monitor IV site closely and convert to central line when feasible

Weaning:

• After maintaining target BP ≥8 hours without catecholamines, taper by 0.005 U/min each hour as tolerated to maintain MAP

Contraindications:

• Hypersensitivity to vasopressin (and to chlorobutanol for multi-dose vial)

Precautions:

• Ischemia-prone states: Coronary, mesenteric, digital, or skin ischemia may occur—risk rises at higher doses or with concomitant high-dose catecholamines
• Cardiac function: May worsen cardiac output in impaired myocardial function; avoid excessive dosing
• Water balance: V2 effects can cause hyponatremia during infusion; reversible diabetes insipidus with hypernatremia may occur after abrupt discontinuation

Ischemic Complications:

• Digital/mesenteric/cutaneous ischemia
• Myocardial ischemia

Cardiac:

• Arrhythmias (including atrial fibrillation)
• Decreased cardiac output

Electrolyte/Water Balance:

• Hyponatremia (during therapy)
• Hypernatremia/polyuria after discontinuation (reversible diabetes insipidus)

Other:

• Local infusion-site complications
• Headache, abdominal cramps, nausea

• Catecholamines: Combined use is standard in septic shock; monitor for additive ischemia
• Indomethacin: May increase vasopressin effect
• Ganglionic blockers: May enhance blood pressure increase
• Furosemide: May decrease antidiuretic effect
• SIADH-promoting drugs (SSRIs, carbamazepine, etc.): May potentiate hyponatremia during vasopressin therapy
• Nitroglycerin: Pair with nitroglycerin infusion for variceal bleeding protocols to mitigate coronary ischemia (institutional)

Perfusion Monitoring:

• MAP ≥65 mmHg (adults) or age-appropriate target
• Capillary refill, mental status
• Urine output
• Lactate trend

Ischemia Monitoring:

• Continuous ECG
• Frequent assessments of digits/skin/abdomen for ischemia
• Troponin if symptoms of myocardial ischemia

Electrolytes & Water Balance:

• Sodium at least daily (q6–12h during initiation)
• Fluid balance/weights
• Watch for polyuria/hypernatremia after stopping—consider DDAVP if diabetes insipidus occurs

Dose-Sparing Effects:

• Document norepinephrine-equivalent dose before/after starting vasopressin
• Follow weaning protocols

• 1. Evans, L., Rhodes, A., Alhazzani, W., et al. (2021). Surviving Sepsis Campaign: International guidelines for management of sepsis and septic shock 2021. Intensive Care Medicine, 47, 1181–1247. https://doi.org/10.1007/s00134-021-06506-y
• 2. Par Pharmaceutical, Inc. (2020). VASOSTRICT (vasopressin) injection, USP — Prescribing Information. U.S. FDA/AccessData.
• 3. Medscape. (2024–2025). Vasopressin (Vasostrict) — Dosing, indications, interactions, adverse effects, and pharmacology.
• 4. Russell, J. A., Walley, K. R., Singer, J., et al. (2008). Vasopressin versus norepinephrine infusion in patients with septic shock (VASST). New England Journal of Medicine, 358, 877–887.
• 5. Gordon, A. C., Mason, A. J., Thirunavukkarasu, N., et al. (2016). Early vasopressin vs norepinephrine in septic shock (VANISH). JAMA, 316(5), 509–518.
• 6. Jozwiak, M., et al. (2022). Vasopressors and risk of acute mesenteric ischemia. Frontiers in Medicine, 9, 826446.
• 7. Panchal, A. R., et al. (2019). Adult basic & advanced life support—AHA Guidelines. Circulation, 140(24), e881–e894.
• 8. Choong, K., et al. (2016). Vasopressin in pediatric critical care. Pediatric Critical Care Medicine, 17(3), 264–275.
• 9. University of Iowa Stead Family Children's Hospital. (2020). Neonatal vasopressin infusion guideline.