Skip to Content
Questions about Atrial Fibrillation? Get answers from our expert.


( 8-Arginine-Vasopressin )

Pronunciation: VAY-so-PRESS-in
Class: Posterior pituitary hormone

Trade Names

Pitressin Synthetic
- Injection 20 pressor units/mL

Pressyn (Canada)
Pressyn AR (Canada)


Promotes resorption of water through kidney. At high doses, stimulates contraction of smooth muscle causing vasoconstriction, increased peristaltic activity, and gall-bladder contractions.

Slideshow: 15 Prostate Cancer Facts You Simply Can't Ignore



T max is about 2 to 8 h.


Majority of dose is metabolized and rapidly destroyed in the liver and kidneys.


T ½ is about 10 to 20 min. About 5% of the dose is excreted unchanged in the urine after 4 h.

Indications and Usage

Treatment of neurogenic diabetes insipidus; prevention and treatment of postoperative abdominal distention; facilitation of abdominal roentgenography.

Unlabeled Uses

Treatment of bleeding esophageal varices.


Standard considerations.

Dosage and Administration

Diabetes Insipidus

IM / SC 5 to 10 unit 2 or 3 times daily as needed. Intranasal injection solution may be given as an individualized dosage intranasally on cotton pledgets, by nasal spray, or dropper.


Reduce dosage proportionally.

Abdominal Distention

IM 5 unit initially; subsequent injections every 3 to 4 h as needed. May increase the dose to 10 unit if necessary.

Abdominal Roentgenography

IM / SC 2 injections of 10 unit each administered 2 h and 30 min before films are exposed.

Bleeding Esophageal Varices

IV Infuse initially at 0.2 to 0.4 unit/min and increase to 0.9 unit/min if necessary.

General Advice

  • Give 1 to 2 glasses of water with dose to prevent skin blanching, abdominal cramps, and nausea.
  • If administering via IV infusion, dilute with 0.9% normal saline or D5W to a concentration of 0.1 to 1 unit/mL. Ensure patency of venous access and use infusion control device.


Store at room temperature. Do not freeze.

Drug Interactions

Alcohol, demeclocycline, heparin, lithium, norepinephrine

May decrease the antidiuretic effect of vasopressin.

Carbamazepine, chlorpropamide, clofibrate, fludrocortisone, tricyclic antidepressants, urea

May potentiate antidiuretic effect of vasopressin.

Ganglionic blocking agents

May markedly increase sensitivity to vasopressin pressor effects.

Laboratory Test Interactions

None well documented.

Adverse Reactions




Abdominal cramps; nausea; vomiting; gas.


Gangrene; ischemic colitis; tissue necrosis (with extravasation); allergic reaction (cardiac arrest, tremor, vertigo, sweating).



Category C .




Local or systemic reactions, including anaphylaxis, may occur.

Special Risk Patients

Use drug with caution in patients with epilepsy, migraine, asthma, heart failure, or any condition where a rapid rise in extracellular water may result in further compromise.

Chronic nephritis with nitrogen retention

Contraindicates use until reasonable nitrogen blood levels have been attained.


Severe vasoconstriction and local tissue necrosis may result if drug extravasates during IV infusion.

Vascular disease

Use extreme caution in patients with vascular disease.

Water intoxication

Water intoxication may occur. Early signs include confusion, drowsiness, listlessness, and headache.



Confusion, lethargy, drowsiness, listlessness, headache.

Patient Information

  • Tell patient to take with 1 to 2 glasses of water to prevent skin blanching, nausea, or abdominal cramping.
  • Caution patient to withhold medication and to notify health care provider of chest pain.
  • Tell patient to report drowsiness, listlessness, and headache to health care provider, and to restrict water intake.
  • Explain that urine output should decrease after use.
  • Tell patient to monitor weight daily.
  • Instruct patient to avoid alcohol intake during therapy.
  • Remind patients with diabetes insipidus to carry appropriate medical identification.

Copyright © 2009 Wolters Kluwer Health.