Schedule H

Intravenous (IV), Intramuscular (IM), Subcutaneous (SC)

• Injection: 20 units/mL in 1 mL ampoule

INDICATIONS + DOSING — FOR CLINICIAN USE ONLY

Primary Indications (Approved / Standard in India)

1. Vasodilatory Shock (Septic Shock) – Adjunct to Catecholamines

Parameter Recommendation

Starting dose 0.01 units/min continuous IV infusion

Titration Increase by 0.005 units/min every 10–15 minutes if MAP remains <65 mmHg

Usual maintenance dose 0.03 units/min

Maximum dose 0.03 units/min (higher doses not recommended due to ischemic risk)

Clinical Notes:

• Reserved for norepinephrine-resistant shock

• Used as catecholamine-sparing agent to reduce norepinephrine requirement

• Central venous access mandatory

• Taper gradually over several hours to prevent rebound hypotension

1. Acute Variceal Haemorrhage (Adjunct to Endoscopic Therapy)

Parameter Recommendation

Starting dose 20 units IV bolus

Titration Not applicable

Usual maintenance dose 0.2–0.4 units/min continuous IV infusion

Maximum dose 0.4 units/min

Clinical Notes:

• Duration: Up to 24–48 hours maximum

• Co-administer with nitroglycerin (IV or sublingual) to reduce coronary vasoconstriction risk

• Terlipressin preferred in current Indian gastroenterology practice due to better safety profile

• Use only when terlipressin unavailable

1. Central Diabetes Insipidus (Acute Management)

Parameter Recommendation

Starting dose IM/SC: 5 units; IV infusion: 0.5 units/hour

Titration Adjust based on urine output and serum sodium

Usual maintenance dose IM/SC: 5–10 units 2–4 times daily; IV: 1–2 units/hour

Maximum dose 10 units per single IM/SC dose

Clinical Notes:

• For acute inpatient management only

• Not suitable for chronic outpatient therapy—desmopressin preferred

• Monitor serum sodium every 6–12 hours

• Target urine output: 1–2 mL/kg/hour

Secondary Indications – Adults (Off-label, if any)

Indication Dose Duration Notes

Refractory Cardiac Arrest — OFF-LABEL 40 units IV single bolus Once during resuscitation Specialist only; may replace first or second dose of adrenaline; ILCOR 2010 included but removed from subsequent guidelines; no survival benefit in RCTs; not in current Indian ACLS protocols

PAEDIATRIC DOSING (Specialist Only)

Primary Indications

1. Paediatric Septic Shock (Catecholamine-Refractory)

Parameter Recommendation

Starting dose 0.0003 units/kg/min IV infusion

Titration Increase by 0.0002 units/kg/min every 15–20 minutes based on response

Usual maintenance dose 0.0005–0.001 units/kg/min

Maximum dose 0.002 units/kg/min

Minimum Age: Not recommended in neonates and infants <1 month except in life-threatening situations under experienced PICU supervision

Mandatory Monitoring:

• Continuous invasive BP monitoring

• Urine output (target ≥1 mL/kg/hour)

• Serum lactate every 4–6 hours

• Peripheral perfusion assessment (capillary refill, extremity colour)

• Serum sodium every 6–8 hours

1. Paediatric Central Diabetes Insipidus (Acute Setting)

Parameter Recommendation

Starting dose SC/IM: 0.1 units/kg

Titration Adjust based on urine output and serum sodium

Usual maintenance dose 0.3–0.6 units/kg/day in 2–3 divided doses

Maximum dose 0.6 units/kg/day

Clinical Notes:

• Short-term use only in acute inpatient setting

• Transition to desmopressin for chronic management

• Monitor serum sodium every 6 hours initially

Secondary Indications – Paediatric Doses (Off-label, if any)

Indication Dose Notes

Refractory Paediatric Cardiac Arrest — OFF-LABEL 0.4 units/kg IV bolus once (max 40 units) Specialist use only; limited paediatric trial data; may be considered as alternative to adrenaline in select refractory cases

Age Restriction Statement: Not recommended in neonates or infants under 1 month of age except in life-threatening circumstances under experienced PICU specialist supervision.

Mild to moderate impairment No dose adjustment required

Severe impairment / ESRD No specific adjustment; monitor closely for water retention and hyponatraemia

Haemodialysis Not significantly dialyzed; no supplemental dosing required

Peritoneal dialysis No data available; use with close monitoring

Additional Notes: Enhanced risk of hyponatraemia and fluid overload in renal impairment; monitor serum sodium and fluid balance closely.

Additional Notes: In patients with variceal bleeding and hepatic decompensation, balance haemostatic benefit against ischemic risk; terlipressin may be preferred if available.

• Known hypersensitivity to vasopressin or any formulation component

• Chronic nephritis with significant nitrogen retention

• Unstable angina or acute coronary syndrome

• Severe coronary artery disease (for bolus or high-dose therapy)

• Advanced peripheral vascular disease with active ischemia

• Elderly patients (increased sensitivity to vasoconstrictive effects)

• Pre-existing hypertension or cardiac disease

• Mild to moderate coronary artery disease

• Peripheral vascular disease

• Risk of mesenteric ischemia at higher doses

• Risk of digital ischemia and skin necrosis

• Hyponatraemia risk with prolonged use

• Sudden discontinuation may cause rebound hypotension

• Concurrent use with other vasoconstrictors (additive ischemic risk)

• Asthma or chronic respiratory conditions (bronchospasm risk)

Aspect Recommendation

Risk category Use with extreme caution; limited safety data

Preferred alternatives Norepinephrine for vasodilatory shock in pregnancy; desmopressin for diabetes insipidus

When may be used Life-threatening situations only (maternal septic shock, cardiac arrest); obstetric intensivist involvement mandatory

Monitoring Uterine activity (can stimulate contractions); fetal heart rate; maternal BP and organ perfusion; uteroplacental blood flow

Aspect Recommendation

Compatibility Likely compatible for short-term critical care use

Expected levels in milk Very low; poor oral bioavailability in infant

Preferred alternatives Desmopressin for chronic diabetes insipidus management

Infant monitoring Feeding behaviour; hydration status; weight gain (if prolonged maternal therapy)

Aspect Recommendation

Starting dose Use lower end of dosing range (e.g., 0.01 units/min for shock)

Titration Slower titration; allow longer intervals between dose adjustments

Specific risks Increased sensitivity to vasoconstriction; higher risk of coronary ischemia, mesenteric ischemia, peripheral gangrene; hyponatraemia risk elevated

Monitoring Close monitoring of cardiovascular status, renal function, serum sodium, peripheral perfusion

Interacting Drug Mechanism/Effect Recommendation

MAO inhibitors Enhanced pressor response Avoid combination; if essential, use significantly reduced vasopressin dose

Norepinephrine, phenylephrine Additive vasoconstriction → tissue ischemia Monitor closely; watch for mesenteric and digital ischemia

Tricyclic antidepressants Enhanced antidiuretic effect → hyponatraemia Monitor serum sodium closely

SSRIs SIADH potentiation → severe hyponatraemia Monitor serum sodium; adjust doses as needed

Carbamazepine Enhanced antidiuretic effect → hyponatraemia Monitor sodium levels closely

Interacting Drug Effect Management

NSAIDs Reduced renal clearance; enhanced antidiuretic effect Monitor for water retention and hyponatraemia

Lithium May antagonize antidiuretic effect Monitor therapeutic response; may need dose adjustment

Loop diuretics, thiazides Altered fluid and electrolyte balance Monitor serum sodium and potassium closely

Nitroglycerin Counteracts coronary vasospasm (beneficial co-administration in variceal bleeding) Often intentionally combined; monitor BP

Corticosteroids May alter fluid balance and potentiate hypertension Monitor blood pressure and fluid status

• Abdominal cramps and nausea

• Headache

• Pallor

• Water retention and hyponatraemia

• Peripheral vasoconstriction (cold extremities)

• Transient blood pressure elevation

• Sweating

• Tremor

Adverse Effect Clinical Significance

Mesenteric ischemia Requires immediate dose reduction or discontinuation; surgical consultation if suspected

Digital ischemia/gangrene Monitor extremities closely; discontinue if progressive

Myocardial ischemia/infarction Especially at high doses or with coronary disease; co-administer nitroglycerin when appropriate

Severe hyponatraemia with seizures Monitor sodium; discontinue and correct electrolytes

Skin necrosis Vesicant if extravasated; use central line; infiltrate phentolamine if extravasation occurs

Cardiac arrhythmias Bradycardia, heart block possible; continuous ECG monitoring required

After initiation/dose change MAP every 15–30 minutes; serum sodium every 6–12 hours; urine output hourly; peripheral perfusion assessment

Ongoing during infusion Continuous invasive BP and ECG monitoring; serum sodium every 12 hours; signs of tissue ischemia (bowel, digits, skin)

Before/during weaning Gradual taper; monitor for rebound hypotension

• Vasopressin Injection IP (various generic manufacturers)

• Vasopin (Sun Pharma)

• Pressyn (Gland Pharma)

Note: Brand availability may vary by region and institution; verify local availability.

Notes:

• Not listed in NLEM 2022

• Variable hospital procurement pricing

• Available through institutional and emergency supply channels

1. Adjunct role in septic shock: Vasopressin is added to norepinephrine (not a replacement) when MAP target not achieved; allows catecholamine-sparing effect

1. Fixed-dose in shock: Unlike catecholamines, vasopressin is typically used at a fixed dose (0.03 units/min) rather than titrated up continuously; doses above 0.04 units/min provide no added benefit but increase ischemic risk

1. Central line essential: Always administer via central venous access for continuous infusions; vesicant with significant tissue necrosis risk if extravasated

1. Slow weaning mandatory: Taper gradually (reduce by 0.005 units/min every 30–60 minutes) once hemodynamics stabilize to prevent rebound hypotension

1. Terlipressin preference: For variceal bleeding, terlipressin is now preferred in Indian gastroenterology practice due to longer half-life and better safety profile; reserve vasopressin when terlipressin unavailable

1. Hyponatraemia vigilance: Monitor serum sodium closely especially with prolonged use; antidiuretic effect can cause significant water retention

vasopressin; vasopressor; septic shock; diabetes insipidus; variceal bleeding; ICU drug; critical care; antidiuretic hormone; tissue ischemia risk; hyponatraemia

RxIndia v1.0 — 05 May 2025

• CDSCO Drug Database

• Indian Pharmacopoeia (IP)

• API Textbook of Medicine

• AIIMS ICU Management Protocols

• ICMR/NCDC Sepsis Management Guidelines

• Indian Society of Critical Care Medicine (ISCCM) Expert Consensus

• Goodman & Gilman's The Pharmacological Basis of Therapeutics

• Harrison's Principles of Internal Medicine

• ILCOR Guidelines (for off-label cardiac arrest indication — marked accordingly)

• VASST Trial and meta-analyses (for shock management evidence)