Vasopressin
Endogenous posterior pituitary nonapeptide — clinically used for vasodilatory shock (ICU), diabetes insipidus, and esophageal variceal hemorrhage.
🔬 Mechanism of Action
Vasopressin (arginine vasopressin, AVP) is a 9-amino-acid cyclic peptide synthesized in the supraoptic and paraventricular nuclei of the hypothalamus and released from the posterior pituitary. It acts on three receptor subtypes: V1a (vascular smooth muscle — vasoconstriction via Gq/phospholipase C), V2 (renal collecting duct — aquaporin-2 insertion via Gs/cAMP), and V1b/V3 (anterior pituitary corticotrophs — ACTH release). In ICU settings, vasopressin at 0.01-0.04 U/min provides catecholamine-sparing vasopressor support in septic shock. Unlike catecholamines, it does not increase myocardial oxygen demand.
Source: PMID: 10796661
📜Background & History
Vasopressin is one of the oldest known peptide hormones, discovered by Sir Henry Dale in 1906. Its dual role in water homeostasis and vascular tone makes it critical in both endocrinology and critical care medicine. In modern ICU practice, vasopressin has become a cornerstone vasopressor in septic shock, included in the Surviving Sepsis Campaign guidelines. Also used in advanced cardiac life support (ACLS) algorithms.
🎯 Research Use Cases
- ✓Septic shock
- ✓Cardiac arrest
- ✓Diabetes insipidus
- ✓Esophageal variceal hemorrhage
- ✓Catecholamine-resistant shock
💉 Dosing Protocol
| Typical Dose | 0.01-0.04 units/min IV infusion |
| Frequency | Continuous IV infusion |
| Half-Life | 0.3 hours |
⚠️Safety & Considerations
Digital/mesenteric ischemia possible at high doses. Hyponatremia risk with V2 effects. Can cause coronary vasoconstriction — use with caution in coronary artery disease. Should be weaned gradually in ICU use.
⚡Interactions & Contraindications
Potentiates effects of other vasopressors. May cause limb/mesenteric ischemia at high doses. Use caution with coronary artery disease. Terlipressin is a longer-acting synthetic analogue used in some countries.
🔗Synergies & Common Stacks
Desmopressin is the clinically refined synthetic analogue with selective V2 agonism. Vasopressin acts on V1a, V2, and V1b receptors for broader hemodynamic effects.