Vasopressor Pregnancy: No available data in pregnant women; may produce tonic uterine contractions that could threaten pregnancy. Clearance increased in 2nd/3rd trimester — dose may need increasing.

Vasopressin

Brand names: Pitressin, Empressin

Vasopressin (antidiuretic hormone) is a peptide hormone used as a vasopressor in vasodilatory shock and in the management of certain forms of variceal bleeding and diabetes insipidus.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: Post-cardiotomy shock: start 0.03 units/minute; Septic shock: start 0.01 units/minute

Route: Intravenous infusion (diluted to 0.1 units/mL or 1 unit/mL in 0.9% NaCl or D5W)

Frequency: Continuous infusion; titrate up by 0.005 units/minute at 10-15 minute intervals until target blood pressure reached

Max: Limited data above 0.1 units/minute (post-cardiotomy shock) and 0.07 units/minute (septic shock)

After target BP maintained for 8 hours without catecholamines, taper by 0.005 units/minute every hour as tolerated. Dilute 20 units/mL single-dose vial before use; discard diluted solution after 18 h at room temperature or 24 h refrigerated.

Dose auto-extracted from US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

Known allergy or hypersensitivity to 8-L-arginine vasopressin (per US label, the 1 mL single-dose vial contains no chlorobutanol)

Side effects

Decreased cardiac output
Bradycardia
Tachyarrhythmias
Hyponatraemia
Ischaemia (coronary, mesenteric, skin, digital)

Interactions

Catecholamines — additive pressor effect on mean arterial pressure
Indomethacin — may prolong effects on cardiac index and systemic vascular resistance
Ganglionic blocking agents / drugs causing SIADH — may increase pressor response
Drugs causing diabetes insipidus — may decrease pressor response

Clinical monograph

How it works

It acts on vascular V1 receptors to cause vasoconstriction and on renal V2 receptors to promote water reabsorption in the collecting ducts.

Prescribing in practice

Potent vasoconstriction can cause myocardial, mesenteric and peripheral ischaemia; use with caution in patients with vascular or coronary disease and administer in a monitored setting.
Should be given by controlled intravenous infusion via a secure line, ideally central, to reduce the risk of severe extravasation injury.
Use with caution in heart failure and conditions where a rapid increase in extracellular water may be hazardous.

Monitoring

Monitor blood pressure, fluid balance, serum sodium and signs of peripheral or organ ischaemia during infusion.

Counselling the patient

This medicine is given in an intensive care or high-dependency setting under close monitoring.
Report any chest pain, abdominal pain or changes in the colour of the hands or feet to the team.

Evidence & guidelines

Vasopressin is recommended as an adjunct vasopressor in vasodilatory shock in critical care guidance and the SPC.

Reference: VASST trial (NEJM 2008); Surviving Sepsis Campaign Guidelines 2021; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Drugs

Pathways