Vasopressin is the hormone the pituitary releases when the body needs to hold on to water. Desmopressin was made from it: the same nine amino acids, changed in two places. Those two changes are the whole story of why one is a hospital vasopressor and the other is a tablet, a nasal spray or a small injection for diabetes insipidus and bleeding disorders.
This page sets the two side by side from their US labels and the chemical record, with dates. Peptide Lexicon explains each molecule on its own in its desmopressin and vasopressin entries; desmopressin's dose units and label figures are on our desmopressin dosage page. Nothing here is a recommendation, and neither drug is something to start, stop or switch without the prescriber.
The two changes
| Vasopressin (arginine vasopressin) | Desmopressin | |
|---|---|---|
| Chemical name | 8-L-arginine vasopressin | 1-deamino-8-D-arginine vasopressin |
| Formula (PubChem) | C46H65N15O12S2 | C46H64N14O12S2 |
| Molecular weight | 1,084.2 Da | 1,069.2 Da |
| Position 1 | Cysteine with its amino group | Amino group removed (deamination) |
| Position 8 | L-arginine | D-arginine (the mirror-image form) |
| Ring | Disulfide bridge 1–6 | Same |
| C-terminus | Glycinamide | Same |
PubChem compound records 644077 and 5311065, read 27 October 2026. The formula difference — one nitrogen and one hydrogen fewer — is the removed amino group; the D-arginine swap changes shape, not formula.
What the changes do is stated on the desmopressin label: the altered structure produced "increased duration of action and a decreased vasopressor action and decreased actions on visceral smooth muscle relative to the enhanced antidiuretic activity", so effective antidiuretic doses are "usually below threshold levels for effects on vascular or visceral smooth muscle" (DDAVP tablets, label February 2021).
Receptors: V1 against V2
The Vasostrict label describes vasopressin's two main actions. On V1 receptors in blood vessel walls it causes vasoconstriction — in the gut, kidney and skin circulations — and it contracts gut smooth muscle; through V3 receptors it releases ACTH and prolactin. On V2 receptors in the kidney it reduces water loss, an action that happens "at lower concentrations typical for the antidiuretic hormone". Desmopressin keeps the V2 action and loses most of the V1 action. That is the whole division of labour: vasopressin is given when the blood vessels need squeezing, desmopressin when the kidneys need to hold water — or, separately, to release clotting factor VIII and von Willebrand factor.
Half-life and duration
| Vasopressin | Desmopressin | |
|---|---|---|
| Half-life (current US label) | Apparent t½ ≤10 minutes at 0.01–0.1 units/min in shock | Terminal t½ 2.8 hours IV (normal kidneys); 4, 6.6 and 8.7 hours with mild, moderate and severe impairment |
| How long the effect lasts | Steady state after 30 minutes of infusion; stops soon after the infusion | Tablets: 0.1–0.2 mg antidiuresis "lasting up to eight hours"; 0.4 mg up to 12 hours |
| Cleared by | Mostly metabolised (liver and kidney); ~6% excreted unchanged | Not metabolised by CYP450; 52% recovered unchanged in urine within 24 hours of an IV dose |
| Oral availability | Not given by mouth | About 0.16% of IV for tablets (DDAVP tablet label) |
Vasostrict label April 2026; DDAVP injection label September 2022; DDAVP tablet label February 2021 — read via openFDA, 27 October 2026. An older generic desmopressin injection label puts the comparison in one sentence: biphasic half-lives of 7.8 and 75.5 minutes for desmopressin, "compared with 2.5 and 14.5 minutes for lysine vasopressin".
What each is approved for in the US
| Vasopressin | Desmopressin | |
|---|---|---|
| Indications | Raise blood pressure in adults with vasodilatory shock who stay hypotensive despite fluids and catecholamines | Central diabetes insipidus; primary nocturnal enuresis (tablets); haemophilia A and type 1 von Willebrand disease with factor VIII above 5% (injection, high-concentration nasal spray) |
| Where it is given | Continuous IV infusion, in hospital | Tablets, nasal spray, IV or subcutaneous injection |
| Not indicated for | — | Nephrogenic diabetes insipidus ("ineffective"); severe type 1 von Willebrand disease |
| US approvals (Drugs@FDA) | Vasostrict, April 2014; 16 vasopressin applications in all, including premixed bags from 2023 and the discontinued Pitressin Tannate | DDAVP from February 1978; 38 desmopressin applications in all |
Drugs@FDA, read 27 October 2026. Two desmopressin products built for a third use — night-time urination in adults — were approved and are now both listed as discontinued: Noctiva nasal spray (approved March 2017) and Nocdurna sublingual tablets (approved June 2018).
Side effects, as each label frames them
The two labels read like opposite ends of the same hormone.
Vasopressin (Vasostrict, April 2026) lists reactions identified in the literature, without frequencies: decreased cardiac output, bradycardia, atrial fibrillation, right heart failure, myocardial ischaemia; ischaemia of the gut, fingers and toes, and skin; decreased platelets and bleeding; acute kidney insufficiency; and hyponatraemia. Its two warnings are worsening cardiac function and reversible diabetes insipidus after the infusion stops — dilute urine and high sodium, which the label says may need more vasopressin "or administration of desmopressin" to correct.
Desmopressin leads with water retention. The DDAVP injection label (September 2022) opens with a boxed warning: desmopressin "can cause hyponatremia", which when severe can lead to "seizures, coma, respiratory arrest, or death". It contraindicates the drug in people at high risk — excessive fluid intake, illnesses that upset fluid balance, loop diuretics, systemic or inhaled glucocorticoids, kidney function below 50 mL/min — and states sodium should be normal before starting and checked within 7 days and at about one month. Other reactions it lists: headache, nausea, abdominal cramps, flushing, injection-site redness and burning pain, blood pressure changes, tachycardia and thrombotic events. A separate warning covers increased thrombosis risk in type IIB von Willebrand disease.
The boxed warning is not on every desmopressin label. On 27 October 2026, openFDA returned 37 desmopressin labels: 20 of the 22 injection labels carry it; none of the 12 oral or 3 nasal labels does — the tablet and spray labels state hyponatraemia as a contraindication and warning instead. Our count, from the label records as returned; label versions differ in date.
When one is given after the other
The labels themselves describe one overlap. After a vasopressin infusion stops, a patient can develop temporary diabetes insipidus, and the Vasostrict label names desmopressin as one way to correct it. The reverse — desmopressin for shock — appears on no US label.
What is not established
- Head-to-head trials in the same indication: the two drugs are approved for different conditions, so the comparison here is label against label, not trial against trial.
- Frequencies for most side effects of either drug: both labels list post-marketing or literature reactions without rates.
- Use outside the labels, including desmopressin products sold online as research peptides, which carry no label and no quality record — our page on how to read a certificate of analysis explains what a seller's document can and cannot show.
Questions about either drug belong with the prescribing clinician, and sodium-related symptoms — headache, confusion, nausea — on desmopressin are a reason to contact one promptly. Desmopressin's place among other approved peptide drugs is on our FDA-approved peptides list.
Sources and dates
- Vasostrict (vasopressin injection) prescribing information, label effective April 2026, via openFDA — read 27 October 2026.
- DDAVP Injection (desmopressin acetate) prescribing information, September 2022, and DDAVP Tablets, February 2021, via openFDA — read 27 October 2026.
- openFDA drug label API, generic name "desmopressin": 37 labels by route and boxed warning — read 27 October 2026.
- Drugs@FDA via openFDA: active ingredients vasopressin (16 records) and desmopressin (38), approval dates and marketing status — read 27 October 2026.
- PubChem compounds 644077 (argipressin) and 5311065 (desmopressin): formulas, weights, synonyms — read 27 October 2026.