Vasopressor
Pregnancy: C
Vasopressin
Brand names: Pitressin, Empressin
Adult dose
Dose: Vasodilatory shock: 0.01–0.04 units/min IV infusion. Oesophageal varices: 0.2–0.4 units/min (max 0.8 units/min)
Route: IV infusion
Frequency: Continuous infusion
Fixed low dose as adjunct to noradrenaline in vasodilatory/septic shock — titrate noradrenaline as primary vasopressor.
Paediatric dose
Dose: 0.0003 units/min/kg
Route: IV infusion
Frequency: Continuous
Paediatric septic shock: 0.0003–0.002 units/kg/min. Max 0.04 units/kg/min. Titrate carefully.
Paediatric weight-based calculator
Paediatric septic shock: 0.0003–0.002 units/kg/min. Max 0.04 units/kg/min. Titrate carefully.
Clinical pearls
- VASST trial: vasopressin 0.03 units/min + noradrenaline: no difference in 28-day mortality vs noradrenaline alone, but noradrenaline-sparing
- Mechanism: V1 receptor — direct smooth muscle vasoconstriction (catecholamine-independent)
- Use as noradrenaline-sparing adjunct in septic shock at FIXED dose (0.03 units/min) — not titrated
- Mesenteric ischaemia risk with high doses — monitor lactate and GI symptoms
- ADH/antidiuretic activity: water retention and hyponatraemia with prolonged use
Contraindications
- Chronic nephritis
- Cardiovascular disease (relative — causes vasoconstriction and increased SVR)
- Hypersensitivity
Side effects
- Hyponatraemia (ADH effect)
- Mesenteric/digital ischaemia (excessive doses)
- Coronary vasoconstriction
- Bradycardia
- Skin necrosis (extravasation)
Interactions
- Noradrenaline — additive vasoconstrictive effect (monitor MAP closely)
- Tricyclic antidepressants — potentiate pressor effect
Monitoring
- MAP (target 65 mmHg)
- Serum sodium
- Serum lactate
- Mesenteric ischaemia signs (rising lactate, GI symptoms)
- Extremities for digital ischaemia
Reference: BNFc; VASST trial (NEJM 2008); Surviving Sepsis Campaign Guidelines 2021. Verify against your local formulary and the latest BNF before prescribing.
Related
Curated clinical cross-links plus same-class fallbacks.