What it is
Vasopressin is a nine-amino-acid peptide hormone, made in the hypothalamus and released from the posterior pituitary. It is also called antidiuretic hormone (ADH), which names its everyday job: keeping water in the body. Its sequence is:
CYFQNCPRG-NH₂
The cysteines at positions 1 and 6 are joined by a disulfide bond, closing the first six amino acids into a ring with a three-amino-acid tail. The human form carries arginine at position 8, which is why the drug is called arginine vasopressin. The Vasostrict label describes its product as synthetic arginine vasopressin.
Two receptors, two jobs
The label's mechanism section names both:
- V1 receptors on the muscle of blood vessels — vasopressin makes them contract, which raises blood pressure;
- V2 receptors in the kidney — vasopressin makes the kidney reabsorb water, concentrating the urine.
In daily life the kidney effect is the one that matters: small changes in vasopressin adjust how much water the body keeps. The blood-vessel effect needs higher levels — and it is the one the medicine is used for.
What it is approved for
One indication, on the current Vasostrict label: to increase blood pressure in adults with vasodilatory shock who remain hypotensive despite fluids and catecholamines (drugs such as noradrenaline). In vasodilatory shock — septic shock is one cause — blood vessels relax so far that blood pressure collapses. Vasopressin is added when the usual measures have not been enough.
It is given only as a continuous intravenous infusion. At the rates used in shock the label gives an apparent half-life of 10 minutes or less; blood levels settle after about 30 minutes.
A label built on the literature
Most labels in this library summarise one or two pivotal trials. Vasostrict's does not. Its clinical-studies section is a single sentence: increases in blood pressure were observed in 7 studies in septic shock and 8 in post-cardiotomy shock (shock after heart surgery). The approved claim is that blood pressure rises; the label makes no survival claim.
Its history in FDA's records is similarly late: the first vasopressin application in Drugs@FDA, Vasostrict, is dated 17 April 2014. FDA application data now list 10 applications: four brand applications (Vasostrict and three premixed or ready-to-use versions, 2020–2024) and six generics, the first approved in 2022.
Safety
The label's warnings follow from the two receptors. On the heart side, vasopressin can worsen cardiac function — a fall in cardiac index. On the kidney side, the body can come to rely on it: after the infusion stops, patients may develop a reversible diabetes insipidus — large volumes of dilute urine and rising blood sodium — so the label asks for electrolytes, fluid status and urine output to be monitored.
Its two close relatives
- Oxytocin is the other nine-amino-acid pituitary hormone. It shares vasopressin's ring and differs at only positions 3 and 8 — enough to give it a different receptor and a different job.
- Desmopressin, the kidney-selective analogue, is vasopressin redesigned: the first residue's amino group removed and position 8 switched to D-arginine. The result lasts longer and acts mostly on the kidney, so it is used to reduce urine rather than to raise blood pressure.
Where it stands
Approved for one hospital indication and available as generics. PubMed indexes 51,311 records for vasopressin, 1,350 tagged as randomised controlled trials (2026-09-24) — a literature dominated by the hormone's physiology and by trials in critical care.
Related reading
Another hormone that regulates fluid and blood pressure is covered in BNP and NT-proBNP. For the size line that keeps vasopressin a peptide, see the 40-amino-acid dividing line.