Vasopressin (ADH)

Overview

Arginine vasopressin (AVP/ADH) is a 9-amino acid neuropeptide produced in hypothalamic paraventricular and supraoptic nuclei and released from the posterior pituitary in response to increased plasma osmolality or decreased blood volume. It is essential for water homeostasis via antidiuresis, and at higher concentrations acts as a powerful vasoconstrictor (hence 'vasopressin'). In critical care, vasopressin is used as a vasopressor in septic shock and as an adjunct to resuscitation algorithms. Its analogs—desmopressin (antidiuresis-selective) and terlipressin (splanchnic-selective)—are more widely used clinically.

Mechanism of Action

Vasopressin activates three receptors: V1a (vascular smooth muscle → vasoconstriction via Gq/PLC/Ca2+ pathway), V1b/V3 (pituitary corticotrophs → ACTH release), and V2 (renal collecting duct → AQP2-mediated antidiuresis via Gs/cAMP/PKA). In septic shock, V1a activation counteracts the profound vasoplegia of vasodilatory shock, restoring vascular tone. V2 activation in the kidney causes AQP2 membrane translocation and maximal water reabsorption, crucial for plasma osmolality regulation. In the brain, AVP modulates social behavior, stress responses, and circadian rhythms.

Potential Benefits

• Critical care vasopressor for vasodilatory/septic shock
• Antidiuresis and plasma osmolality regulation
• Cardiac arrest vasopressor in ACLS protocols
• Template for desmopressin and terlipressin development
• Neuromodulator for social behavior and stress responses

Research Dosage Notes

The following reflects doses used in published research studies. This is not medical advice.

Septic shock: 0.03–0.04 units/min IV continuous infusion (adjunct to norepinephrine). Cardiac arrest: 40 units IV bolus (single dose in ACLS). Central DI: 5-10 units IM/SC q4-8h.

Amino Acid Sequence

Side Effects & Safety

• Hypertension and excessive vasoconstriction
• Peripheral ischemia at high doses
• Hyponatremia
• Cardiac arrhythmias
• Mesenteric ischemia at high doses

Synergistic Compounds

The following compounds have been studied alongside Vasopressin (ADH) for potential complementary or synergistic effects:

Related Peptides

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References & Further Reading

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