Vasopressin Pediatric Dose — Cardiovascular Infusions
Vasopressin is a synthetic antidiuretic hormone (ADH) analogue that acts as a potent vasoconstrictor through V1 receptor–mediated smooth muscle contraction, with additional antidiuretic effects via V2 receptors. In the pediatric critical care setting, it is used as a vasopressor infusion for the management of vasodilatory or refractory shock. Unlike catecholamine vasopressors, vasopressin acts through a catecholamine-independent pathway, making it a valuable adjunct in distributive shock states.
Pediatric Dosing
For pediatric patients in shock, vasopressin is initiated as a continuous intravenous infusion at 0.5–2 milliunits/kg/min and titrated based on blood pressure response. This weight-based dosing applies to children weighing less than 40 kg.
- Initial infusion: 0.5 milliunits/kg/min (minimum) to 2 milliunits/kg/min (maximum starting range)
- Titration: Adjust dose incrementally based on hemodynamic (BP) response
- Adults (≥ 40 kg): Dosing is not weight-based; the adult initial infusion dose is 20–100 mcg/min regardless of body weight
Worked example: For a 20 kg child, the initial infusion range is 20 × 0.5 = 10 milliunits/min to 20 × 2 = 40 milliunits/min. Titrate within this range to achieve target blood pressure. Consult institutional protocol for maximum infusion rate and concentration preparation.
Indications and Clinical Context
Vasopressin infusion is indicated in pediatric patients with vasodilatory or distributive shock (e.g., septic shock, post-cardiac surgery vasoplegic syndrome) who demonstrate an inadequate response to initial fluid resuscitation and first-line catecholamine vasopressors such as norepinephrine or dopamine. Its catecholamine-independent mechanism of vasoconstriction provides complementary hemodynamic support and may allow for dose reduction of concurrent vasopressors. Use in pediatric shock aligns with advanced resuscitation principles for refractory hemodynamic instability as outlined in PALS and critical care guidelines.
The transition to fixed, non–weight-based dosing in adults (≥ 40 kg) reflects pharmacodynamic differences and established adult dosing conventions; this distinction should be clearly observed when caring for adolescent patients near or above this weight threshold.
Administration and Monitoring
Vasopressin must be administered as a continuous IV infusion via a dedicated central or peripheral venous line; intraosseous (IO) access may be used in emergent situations when central access is unavailable. Infusion concentration and preparation should follow institutional pharmacy protocols. Dose titration should be guided by serial blood pressure assessments and overall hemodynamic monitoring, including heart rate and end-organ perfusion markers.
- Route: Continuous IV infusion preferred; IO acceptable in emergencies
- Monitoring: Continuous blood pressure monitoring, urine output, serum sodium, and signs of end-organ ischemia
- Key adverse effects: Peripheral and mesenteric vasoconstriction, hyponatremia (with prolonged use), skin/tissue ischemia at high doses
- Contraindications/cautions: Use with caution in patients with pre-existing coronary artery disease or significant cardiac dysfunction; consult institutional protocol for maximum dose limits
Disclaimer: This article is an educational reference summarizing standard pediatric dosing values. It is not a substitute for clinical judgment. Always verify doses against institutional protocols, the current edition of authoritative references (e.g., Lexicomp, Harriet Lane Handbook, PALS guidelines), the patient’s accurate weight, and any patient-specific factors (renal/hepatic function, allergies, comedications) before administration.