Schedule H

Oral, Intravenous

• Tablets: 100 mg, 200 mg

• Injection: 150 mg/3 mL (50 mg/mL) ampoule

INDICATIONS + DOSING — FOR CLINICIAN USE ONLY

Primary Indications (Approved / Standard in India)

1. Ventricular Tachyarrhythmias (VT/VF, particularly in structural heart disease)

A. Intravenous Route (Acute/Emergency Setting)

Parameter Recommendation

Starting dose (Loading) 150 mg IV over 10 minutes (dilute in 100 mL 5% dextrose)

Titration 1 mg/min for 6 hours → then 0.5 mg/min for 18 hours

Usual maintenance dose Convert to oral therapy after stabilization

Maximum dose 2.2 g IV in first 24 hours

B. Oral Route (Maintenance/Chronic Therapy)

Parameter Recommendation

Starting dose (Loading) 800–1200 mg/day in 2–3 divided doses for 1–2 weeks

Titration Reduce by 200 mg every 5–7 days based on response

Usual maintenance dose 200–400 mg once daily

Maximum dose 600 mg/day (short-term); 400 mg/day preferred for chronic use

Clinical Notes:

• Adjust dosing based on rhythm control response and safety parameters

• Long half-life (40–55 days) necessitates loading phase

• ECG monitoring mandatory during IV administration

1. Supraventricular Tachyarrhythmias (Atrial Fibrillation — rhythm control in structural heart disease or LV dysfunction)

Parameter Recommendation

Starting dose (Loading) 600–800 mg/day in divided doses for 1 week

Titration Reduce by 200 mg every 5–7 days

Usual maintenance dose 100–400 mg once daily

Maximum dose 400 mg/day for long-term use

Clinical Notes:

• Initiate only when cardioversion is planned or in recurrent AF

• Preferred in patients with heart failure or structural heart disease where other antiarrhythmics are contraindicated

• Not first-line for lone AF

1. Prevention of Recurrent VT/VF in ICD Patients (Adjunct to Device Therapy)

Parameter Recommendation

Starting dose 400 mg/day in divided doses for 1–2 weeks

Titration Reduce based on ICD interrogation and arrhythmia burden

Usual maintenance dose 100–200 mg once daily

Maximum dose 400 mg/day

Clinical Notes:

• Used to reduce frequency of appropriate ICD shocks

• Lower maintenance doses preferred to minimize toxicity

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

Indication Dose Duration Supervision Label Status Evidence Basis

Acute rate control in atrial fibrillation (when beta-blockers/CCBs contraindicated) 150 mg IV over 10–15 min, then 1 mg/min × 6 hours, then 0.5 mg/min Until rate controlled Specialist/ICU only OFF-LABEL RCTs in acute AF; not first-line per ICMR/API guidelines

PAEDIATRIC DOSING (Specialist Only)

Primary Indications

Supraventricular Tachycardia (SVT) or Ventricular Tachycardia

A. Intravenous Route (ICU/Specialist Setting Only)

Parameter Recommendation

Starting dose (Loading) 5 mg/kg IV over 20–60 minutes (dilute in D5W)

Titration May repeat loading dose; total up to 15 mg/kg/day

Usual maintenance dose 5–15 mcg/kg/min continuous infusion

Maximum dose 15 mg/kg/day OR 1.5 mg/kg/day maintenance

B. Oral Route (After Stabilization)

Parameter Recommendation

Starting dose (Loading) 10–15 mg/kg/day in 2–3 divided doses for 5–10 days

Titration Reduce gradually based on arrhythmia control

Usual maintenance dose 5–10 mg/kg/day in 1–2 divided doses

Maximum dose 200–400 mg/day (weight and age dependent)

Age Restrictions:

• NOT recommended below 1 year of age except under paediatric cardiology supervision in tertiary care

Safety Monitoring:

• Baseline: ECG (QTc), LFTs, TFTs, chest X-ray

• Ophthalmology examination if use exceeds 6 months

• Monitor growth parameters

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

Indication Dose Duration Supervision Label Status Evidence Basis

Fetal tachyarrhythmia (via maternal administration) Individualized maternal dosing Until delivery/resolution Maternal-fetal medicine + Paediatric cardiology OFF-LABEL Case series from Indian referral centres

• Sinus node dysfunction (unless permanent pacemaker in situ)

• Second-degree or third-degree AV block (unless permanent pacemaker in situ)

• Severe sinus bradycardia (<50 bpm, symptomatic)

• Known hypersensitivity to amiodarone or iodine

• Severe thyroid dysfunction (overt hyperthyroidism or hypothyroidism)

• Pregnancy (except for life-threatening arrhythmias — see Pregnancy section)

• Concurrent use of drugs causing torsades de pointes with no monitoring capability

• Pre-existing pulmonary disease — increased risk of amiodarone-induced pulmonary toxicity

• Thyroid disorders — can cause both hypothyroidism and hyperthyroidism

• Hepatic dysfunction — hepatotoxicity risk even with normal baseline LFTs

• Baseline QT prolongation — risk of torsades de pointes

• Electrolyte abnormalities — correct hypokalaemia and hypomagnesaemia before initiation

• Photosensitivity — advise sun protection measures

• Corneal microdeposits — usually asymptomatic but may cause visual halos

• Elderly patients — increased sensitivity to all adverse effects

• Concurrent use of other negative chronotropes

Parameter Recommendation

Risk category/Safety statement Avoid — crosses placenta; associated with fetal thyroid dysfunction, goitre, growth restriction, and neurodevelopmental concerns

Preferred alternatives Beta-blockers (metoprolol, propranolol) or digoxin depending on arrhythmia type

When it may be used Life-threatening arrhythmias refractory to safer alternatives; specialist decision only

Monitoring Maternal: ECG, LFTs, TFTs; Fetal: serial ultrasound for growth, thyroid size, cardiac function

Parameter Recommendation

Compatibility Not recommended — significant excretion into breast milk

Preferred alternatives Propranolol, sotalol (if appropriate for indication)

Expected drug levels in milk Moderate to high; infant receives significant iodine load

Infant monitoring If unavoidable: monitor infant TFTs, weight gain, feeding patterns, cardiac status

Parameter Recommendation

Starting dose 100–200 mg/day oral; lower IV loading doses may be considered

Titration Slower titration recommended; assess response over weeks

Extra risks Enhanced susceptibility to bradycardia, hypotension, thyroid dysfunction, pulmonary toxicity, hepatotoxicity; falls risk with hypotension; polypharmacy interactions common

Interacting Drug Effect/Mechanism Recommendation

Digoxin Increased digoxin levels (inhibits P-glycoprotein) Reduce digoxin dose by 50%; monitor levels

Warfarin Increased INR (CYP2C9 inhibition) Reduce warfarin by 30–50%; monitor INR frequently

Simvastatin Increased myopathy/rhabdomyolysis risk (CYP3A4 inhibition) Limit simvastatin to ≤20 mg/day; consider alternative statin

QT-prolonging drugs (fluoroquinolones, macrolides, azole antifungals, antipsychotics, ondansetron) Additive QT prolongation; risk of torsades de pointes Avoid combination or ensure ECG monitoring

Strong CYP3A4 inhibitors (ketoconazole, itraconazole, ritonavir) Increased amiodarone levels and toxicity Avoid or reduce amiodarone dose

Grapefruit juice Increased amiodarone absorption and levels Avoid concurrent intake

Interacting Drug Effect/Mechanism Recommendation

Beta-blockers Additive bradycardia and AV block Use with caution; monitor heart rate and ECG

Diltiazem, Verapamil Additive negative chronotropic and dromotropic effects Monitor for bradycardia; avoid high doses

Phenytoin Increased phenytoin levels (CYP2C9 inhibition) Monitor phenytoin levels; adjust dose if needed

Rifampicin Decreased amiodarone efficacy (CYP3A4 induction) Monitor for loss of arrhythmia control

Ciclosporin Increased ciclosporin levels Monitor ciclosporin levels

Aluminium/magnesium antacids May reduce oral amiodarone absorption Separate administration by 2 hours

Fentanyl Enhanced cardiovascular depression Use with caution in perioperative settings

• Corneal microdeposits (>90% with long-term use; usually asymptomatic, may cause visual halos)

• Photosensitivity and blue-grey skin discolouration

• Bradycardia

• Nausea, anorexia, constipation

• Hypothyroidism (more common) or hyperthyroidism

• Elevated hepatic transaminases (usually asymptomatic)

• Tremor, ataxia, peripheral neuropathy

• Sleep disturbances

Adverse Effect Clinical Action

Pulmonary toxicity (pneumonitis, fibrosis) Potentially fatal; discontinue immediately; may require corticosteroids

Hepatotoxicity (transaminases >3× ULN or clinical hepatitis) Discontinue; monitor for recovery

Torsades de pointes Rare but life-threatening; discontinue; correct electrolytes; may need pacing

Optic neuritis/neuropathy Can cause permanent vision loss; discontinue immediately

Thyroid storm (amiodarone-induced thyrotoxicosis) Medical emergency; specialist management required

Severe bradycardia/sinus arrest/complete heart block May require pacing; discontinue if possible

Stevens-Johnson Syndrome/TEN Discontinue immediately; supportive care

After initiation (first 3–6 months) ECG: after loading and at 1, 3 months; LFTs: monthly for 3 months then 3-monthly; TFTs: at 3 months

Long-term (chronic use) TFTs and LFTs: every 6 months; ECG: every 6 months; Chest X-ray: annually or with symptoms; Ophthalmology: annually or if visual symptoms; Pulmonary function/HRCT: if new respiratory symptoms

Brand Name Manufacturer Formulation

Cordarone Sanofi Tablets 200 mg, Injection

Cordarone X Pfizer Tablets 200 mg

Amiodon Samarth Tablets 100 mg, 200 mg

Duron Intas Tablets 200 mg

Eurythmic Micro Labs Tablets 100 mg, 200 mg; Injection

Aldarone Alkem Tablets 200 mg

Note: Also available as hospital-supply generics

Note: Not currently under DPCO/NLEM price control. Prices vary between government and private supply chains.

1. Loading is mandatory: Due to extremely long half-life (40–55 days) and high volume of distribution, adequate loading is essential before maintenance.

1. Thyroid vigilance: Contains ~37% iodine by weight; inhibits peripheral T4→T3 conversion. Both hypo- and hyperthyroidism can occur — hyperthyroidism is more dangerous and may require thyroidectomy.

1. Pulmonary toxicity is unpredictable: Not strictly dose-dependent; can occur at any dose. Annual chest X-ray and immediate evaluation for new respiratory symptoms essential.

1. Drug interactions are extensive: Always review concomitant medications. Reduce digoxin by 50% and warfarin by 30–50% when initiating amiodarone.

1. Effects persist after stopping: Due to tissue accumulation, adverse effects and drug interactions may persist for weeks to months after discontinuation.

1. Preferred in structural heart disease: Amiodarone is the antiarrhythmic of choice for VT/VF and AF in patients with heart failure or significant LV dysfunction where other agents are contraindicated.

antiarrhythmic; amiodarone; atrial fibrillation; ventricular tachycardia; VF; cardiology; QT prolongation; thyroid monitoring; pulmonary toxicity; CYP3A4 inhibitor; renal-safe

RxIndia v1.0 — 01 Apr 2025

• CDSCO approved prescribing information

• Indian Pharmacopoeia / National Formulary of India

• API Textbook of Medicine

• Harrison's Principles of Internal Medicine

• AIIMS Pharmacology Department protocols

• ICMR Guidelines on Atrial Fibrillation and Ventricular Arrhythmia Management

• Cardiological Society of India practice recommendations

• Select RCTs/meta-analyses (for off-label IV rate control indication)