Vasopressin Analogue 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 (ICU)

Brand names: Pitressin

Vasopressin (antidiuretic hormone) is used in intensive care as a vasopressor adjunct, typically added to catecholamines in septic and other vasodilatory shock states.

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. ICU variant — same US label as vasopressin.

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

Acting on vascular V1 receptors it causes potent vasoconstriction through a catecholamine-independent pathway, raising systemic vascular resistance and mean arterial pressure.

Prescribing in practice

Its intense vasoconstriction can provoke cardiac, mesenteric, and peripheral/digital ischaemia, so it is titrated carefully and delivered via central access with continuous monitoring.
It is generally used as a fixed-rate adjunct to noradrenaline rather than titrated alone as a first-line vasopressor.
Caution is needed in coronary artery disease and where splanchnic or peripheral perfusion is already compromised.

Monitoring

Monitor mean arterial pressure, peripheral and digital perfusion, urine output, and for signs of mesenteric or cardiac ischaemia during the infusion.

Counselling the patient

Explain to the team that vasopressin is an adjunct to catecholamine vasopressors and given by central line.
Highlight the need to watch extremities and mesenteric perfusion for ischaemia.
Note that it should not be abruptly stopped without considering the effect on blood pressure.

Evidence & guidelines

The VASST trial informs the use of vasopressin as an adjunct to noradrenaline in septic shock, and it features in international Surviving Sepsis Campaign recommendations.

Reference: VASST trial; Surviving Sepsis Campaign guidelines; 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