Schedule H

Intravenous (IV bolus only)

• Injection: 3 mg/mL (2 mL ampoule = 6 mg)

• Injection: 3 mg/mL (5 mL vial = 15 mg)

INDICATIONS + DOSING — FOR CLINICIAN USE ONLY

Primary Indications (Approved / Standard in India)

Paroxysmal Supraventricular Tachycardia (PSVT) — Acute Termination

(Including AV nodal re-entrant tachycardia [AVNRT] and orthodromic AV re-entry via accessory pathways)

Dosing Protocol (Adults):

Step Dose Administration

Initial dose 6 mg rapid IV bolus over 1–2 seconds Follow immediately with ≥20 mL normal saline flush

If no response in 1–2 minutes 12 mg rapid IV bolus Repeat saline flush

If still no response in 1–2 minutes 12 mg rapid IV bolus (final dose) Repeat saline flush

Parameter Details

Starting dose 6 mg IV bolus

Titration Increase to 12 mg if no response; may repeat 12 mg once

Usual maintenance dose Not applicable — single acute episode treatment

Maximum dose 30 mg total per episode (6 mg + 12 mg + 12 mg)

Clinical Notes:

• Administer via large-bore peripheral IV or central line (preferably antecubital fossa)

• Continuous ECG monitoring mandatory throughout administration

• Resuscitation equipment must be immediately available

• Transient asystole (2–6 seconds) is expected and usually self-limiting

• NOT effective for atrial fibrillation, atrial flutter, or ventricular tachycardia

• AVOID in irregular wide-complex tachycardias (possible pre-excited atrial fibrillation)

Secondary Indications — Adults Only (Off-label)

Indication Dose Duration Remarks

Diagnostic aid for tachyarrhythmia differentiation — OFF-LABEL 6–12 mg IV bolus with ECG observation Single administration Specialist only (Cardiologist/Electrophysiologist); transient AV nodal block helps distinguish SVT from VT; diagnostic tool only, not therapeutic; international electrophysiology practice; used in Indian cardiology centres

PAEDIATRIC DOSING (Specialist Only)

Primary Indication: Paroxysmal Supraventricular Tachycardia (PSVT) — Acute Termination

Route: IV bolus via large peripheral or central vein; follow immediately with normal saline flush (≥5 mL in infants, ≥10 mL in older children)

Weight Category Initial Dose Subsequent Doses Maximum Single Dose

<50 kg 0.1 mg/kg IV bolus May repeat at 0.2 mg/kg if no response in 1–2 minutes 6 mg

≥50 kg 6 mg IV bolus (adult protocol) 12 mg if no response; may repeat 12 mg once 12 mg

Parameter Details

Starting dose 0.1 mg/kg IV bolus (maximum 6 mg)

Titration Double to 0.2 mg/kg if no response in 1–2 minutes

Usual maintenance dose Not applicable — single acute episode treatment

Maximum dose 0.3 mg/kg or 12 mg (whichever is lower) per episode

Monitoring:

• Continuous ECG monitoring mandatory

• Resuscitation equipment immediately available

• Document rhythm strip before, during, and after administration

Clinical Notes:

• Stop administration if conversion occurs

• Flush volume: 5–10 mL in infants/young children; 10–20 mL in older children

Secondary Indications — Paediatric (Off-label)

Not applicable — No validated off-label paediatric indications beyond PSVT.

⚠️ Not recommended in neonates or infants <1 month of age except under paediatric cardiology supervision with documented justification and full resuscitation capability.

• Second-degree or third-degree AV block (without functioning permanent pacemaker)

• Sick sinus syndrome (without functioning permanent pacemaker)

• Known hypersensitivity to adenosine

• Bronchospastic lung disease — asthma (including history of bronchospasm) or severe COPD

• Long QT syndrome — risk of torsades de pointes

• Decompensated heart failure with haemodynamic instability

• Pre-excited atrial fibrillation (WPW syndrome with AF) — risk of ventricular fibrillation

• Recent heart transplant (within 1 year) — increased sensitivity to adenosine; consider reduced starting dose (3 mg)

• Wolff-Parkinson-White (WPW) syndrome — avoid if atrial fibrillation suspected; risk of inducing ventricular fibrillation

• Seizure disorders — rare reports of seizure precipitation

• Autonomic dysfunction — exaggerated haemodynamic response possible

• Moderate COPD or reactive airway disease — use with extreme caution; may precipitate bronchospasm

• Gout or hyperuricaemia — theoretical purine load concern with repeated dosing

• Wide-complex tachycardia of uncertain origin — use only if SVT mechanism confirmed

• Concomitant use of drugs affecting AV conduction — enhanced bradycardia risk

Parameter Details

Safety Category Generally considered safe for acute use; no teratogenicity reported

Pharmacokinetics Extremely rapid plasma clearance (<10 seconds half-life); minimal fetal exposure expected

Preferred alternatives Vagal manoeuvres first; adenosine is first-line pharmacological therapy for PSVT in pregnancy

When to use May be used for life-threatening or symptomatic PSVT when vagal manoeuvres fail; included in AIIMS protocols

Monitoring Continuous maternal ECG; fetal heart rate monitoring if viable pregnancy; immediate obstetric support available

Parameter Details

Compatibility Compatible with breastfeeding

Drug levels in milk Negligible — plasma half-life <10 seconds precludes significant transfer to breastmilk

Preferred alternatives Not applicable — adenosine is appropriate for acute PSVT

Infant monitoring No specific monitoring required; no interruption of breastfeeding necessary

Parameter Recommendation

Starting dose Standard adult dose (6 mg IV bolus) — no age-based reduction required

Titration Standard protocol (escalate to 12 mg if no response)

Special considerations Slightly increased sensitivity possible; higher prevalence of conduction disease — ensure absence of occult AV block

Additional risks Enhanced risk of prolonged bradycardia or asystole with underlying conduction system disease; monitor closely under continuous ECG

Drug Mechanism Clinical Effect Recommendation

Dipyridamole Inhibits cellular uptake and metabolism of adenosine Markedly enhanced and prolonged adenosine effect Reduce adenosine dose to 1–2 mg initially; avoid if possible

Theophylline, Aminophylline Competitive adenosine receptor antagonism Markedly reduced or abolished adenosine efficacy May require substantially higher adenosine doses (up to 2–3 fold); consider alternative therapy

Caffeine (high doses) Adenosine receptor antagonism Reduced adenosine efficacy May require increased adenosine doses

Carbamazepine Enhanced AV nodal depression Increased risk of prolonged AV block Use with caution; enhanced monitoring required

Drug Interaction Recommendation

Beta-blockers (metoprolol, propranolol, atenolol) Additive AV nodal depression Not contraindicated; monitor for enhanced bradycardia/asystole; ensure resuscitation readiness

Non-dihydropyridine calcium channel blockers (verapamil, diltiazem) Additive AV nodal depression Monitor for prolonged bradycardia; use with caution

Digoxin Additive AV nodal effect; theoretical proarrhythmic risk in WPW Careful ECG monitoring; avoid in pre-excited atrial fibrillation

Antipsychotics (haloperidol, risperidone, clozapine) QT prolongation; additive bradyarrhythmia risk ECG monitoring if concurrent use required

Nicotine May reduce adenosine efficacy May require slightly higher doses in heavy smokers

• Facial flushing (most common)

• Chest discomfort, tightness, or pressure

• Dyspnoea (transient; usually <30 seconds)

• Dizziness or lightheadedness

• Nausea

• Headache

• Metallic taste

• Palpitations

• Transient sinus bradycardia

• Brief asystole (expected; usually 2–6 seconds)

Note: Adverse effects are typically transient (lasting <1 minute) due to extremely short half-life.

• Prolonged asystole — usually self-limiting; if >15 seconds, consider external pacing; extremely rare

• Sustained bradycardia — may require atropine or temporary pacing

• Bronchospasm — in patients with reactive airway disease; treat with bronchodilators; may require discontinuation of further doses

• Ventricular fibrillation — in patients with pre-excited atrial fibrillation (WPW with AF); requires immediate defibrillation

• Atrial fibrillation — transient; usually self-terminating

• Hypotension — usually transient; may require supportive care

• Seizures — very rare; manage supportively

• Complete heart block — rare; may require temporary pacing

⚠️ Resuscitation equipment and trained personnel must be immediately available during administration.

Phase Parameters

Baseline 12-lead ECG (document rhythm); vital signs (BP, HR, SpO₂); electrolytes (K⁺, Mg²⁺) if aetiology unclear; confirm absence of contraindications

During administration Continuous ECG monitoring (rhythm strip recording); blood pressure; resuscitation equipment ready; defibrillator available

Post-administration ECG to confirm rhythm conversion; monitor for recurrence; vital signs until stable

Long-term Not applicable — acute use only

• Adenojet® (Samarth)

• Adenocor® (Sanofi)

• Adekin® (Neon)

• Adesol® (Sun Pharma)

• Adenocard® (limited availability)

Note: Often available in emergency/ACLS kits in hospitals.

Note: Not included in NLEM 2022; not NPPA price-controlled; prices vary by institution and supply chain.

• Administration technique critical: Administer as rapid IV push (1–2 seconds) through large-bore IV in antecubital fossa, immediately followed by ≥20 mL rapid saline flush with arm elevation — slow administration or inadequate flush results in drug degradation before reaching heart

• Expect transient asystole: Brief asystole (2–6 seconds) is expected and therapeutic — do NOT panic; continue ECG observation; rhythm usually resumes spontaneously

• Central line consideration: If using central venous access, reduce saline flush to 10 mL; drug reaches heart faster

• Heart transplant patients: Denervated heart has increased adenosine sensitivity — start with 3 mg initial dose

• Theophylline/caffeine effect: Patients on methylxanthines may require 2–3 fold higher doses or may not respond — consider alternative therapy

• NOT for AF/flutter/VT: Adenosine does not terminate atrial fibrillation, atrial flutter, or ventricular tachycardia — use only for re-entrant SVT involving AV node

adenosine; antiarrhythmic; PSVT; supraventricular tachycardia; AVNRT; emergency medicine; ACLS; IV bolus; pregnancy-safe; paediatric dosing; AV node; Schedule H; India

RxIndia v1.0 — 07 May 2025

• CDSCO approved prescribing information

• Indian Pharmacopoeia/NFI 2021

• API Textbook of Medicine — Cardiac Arrhythmias

• AIIMS Emergency Medicine Drug Protocols

• NCDC ACLS Guidelines

• Indian Academy of Pediatrics (IAP) Emergency Care Guidelines

• Goodman & Gilman's The Pharmacological Basis of Therapeutics

• Harrison's Principles of Internal Medicine