Isoproterenol Uses, Dosage, Side Effects & Warnings | DrugsAtlas
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DRUG NAME: Isoproterenol
Therapeutic Class: Sympathomimetic (Adrenergic Agonist)
Subclass: Non-selective Beta-Adrenergic Agonist
Speciality: Emergency Medicine
Schedule (India): Schedule H
Route(s): Intravenous (IV), Intramuscular (IM), Subcutaneous (SC)
Formulations Available in India:
- Injection: 0.2 mg/mL (1 mL ampoule)
- Injection: 1 mg/5 mL vial (0.2 mg/mL)
- Inhalation solution: NOT AVAILABLE in India
INDICATIONS + DOSING — FOR CLINICIAN USE ONLY
Primary Indications (Approved / Standard in India)
▶ 1. Bradyarrhythmias (including heart block — as bridge therapy while awaiting transvenous pacemaker)
Method A: IV Bolus followed by Infusion
| Parameter | Recommendation |
|
Starting dose
|
5 mcg IV bolus (slow injection over 1 minute) |
|
Titration
|
Repeat 5 mcg bolus every 2–3 minutes if inadequate response; then commence infusion |
|
Usual maintenance dose
|
0.5–10 mcg/min IV infusion |
|
Maximum dose
|
10 mcg/min (rarely exceeding this) |
Method B: Weight-Based Infusion (Alternative)
| Parameter | Recommendation |
|
Starting dose
|
0.01–0.02 mcg/kg/min IV infusion |
|
Titration
|
Increase by 0.01 mcg/kg/min every 10–15 minutes based on heart rate response |
|
Usual maintenance dose
|
0.03–0.10 mcg/kg/min |
|
Maximum dose
|
0.20 mcg/kg/min |
Clinical Notes:
- Continuous ECG monitoring mandatory throughout administration
- Titrate to achieve target heart rate (typically 60–80 bpm)
- Avoid in ischaemic heart disease due to increased myocardial oxygen demand
- Use as temporising measure only — not definitive therapy
- Hospital/ICU setting with specialist supervision required
- Method A (bolus + infusion) preferred for rapid onset; Method B (weight-based) preferred in paediatrics and for precise titration
▶ 2. Torsades de Pointes (temporary bridge therapy)
| Parameter | Recommendation |
|
Starting dose
|
1–2 mcg/min IV infusion |
|
Titration
|
Increase by 1–2 mcg/min every 5–10 minutes to shorten QT interval |
|
Usual maintenance dose
|
2–10 mcg/min |
|
Maximum dose
|
10 mcg/min |
Clinical Notes:
- Specialist cardiac care setting only
- Use while magnesium sulphate, overdrive pacing, or definitive therapy is arranged
- Target: Increase heart rate to 90–110 bpm to suppress pause-dependent arrhythmia
- Not first-line — magnesium is preferred initial therapy
▶ 3. Adjunct in Cardiac Arrest (temporising agent when standard therapy exhausted)
| Parameter | Recommendation |
|
Starting dose
|
1 mcg/min IV infusion |
|
Titration
|
Increase based on clinical response |
|
Usual maintenance dose
|
1–5 mcg/min |
|
Maximum dose
|
10 mcg/min |
Clinical Notes:
- Short-term use only
- Not for routine cardiac arrest management
- Consider only when atropine and pacing have failed or are unavailable
Secondary Indications — Adults Only (Off-label)
| Indication | Dosing | Duration | Notes |
|
Septic shock with bradycardia unresponsive to other agents — OFF-LABEL
|
Starting dose: 1 mcg/min IV; Titration: Increase by 1–2 mcg/min every 10 min; Usual range: 1–10 mcg/min; Maximum: 10 mcg/min | Short-term bridge while alternative measures instituted | Specialist only. Used when bradycardia limits norepinephrine therapy. Evidence basis: Case series; Indian critical care practice |
PAEDIATRIC DOSING (Specialist Only)
Primary Indications (Approved / Standard in India)
▶ Paediatric Bradycardia (congenital heart block, drug-induced bradycardia)
Weight-Based IV Infusion Dosing:
| Age Group | Starting Dose | Titration | Usual Maintenance | Maximum Dose |
|
Neonates
|
0.02–0.05 mcg/kg/min IV | Increase by 0.01–0.02 mcg/kg/min every 10–15 min | 0.05–0.20 mcg/kg/min | 0.30 mcg/kg/min |
|
Infants (1 month – 1 year)
|
0.02–0.05 mcg/kg/min IV | Increase by 0.01–0.02 mcg/kg/min every 10–15 min | 0.05–0.15 mcg/kg/min | 0.20 mcg/kg/min |
|
Children (1–12 years)
|
0.02–0.05 mcg/kg/min IV | Increase by 0.01–0.02 mcg/kg/min every 10–15 min | 0.05–0.15 mcg/kg/min | 0.20 mcg/kg/min |
|
Adolescents (>12 years)
|
5 mcg IV bolus OR 0.02 mcg/kg/min IV infusion | As per adult protocol | 0.5–10 mcg/min OR 0.03–0.10 mcg/kg/min | 10 mcg/min |
Clinical Notes:
- Continuous cardiac monitoring mandatory
- Weight-based dosing preferred in children for precise titration
- Not recommended in tachyarrhythmia or post-cardiac surgery tachycardia without electrophysiology input
- Use as bridge to pacing in symptomatic bradycardia
Secondary Indications — Paediatrics (Off-label)
| Indication | Details |
|
Paediatric Torsades de Pointes — OFF-LABEL
|
Specialist only; same weight-based dosing as above; not first-line (magnesium and pacing preferred). Limited evidence in paediatric population. |
Safety Monitoring (Paediatric):
- Continuous ECG and SpO2 monitoring
- Blood pressure monitoring every 5–15 minutes during titration
- Serum glucose monitoring (risk of hypoglycaemia in neonates)
- Serum potassium monitoring
- Watch for tachyarrhythmias — discontinue if sustained ventricular tachycardia occurs
Age Restrictions:
- Not recommended below neonatal age except under specialist supervision in NICU/PICU setting
RENAL ADJUSTMENT
| Renal Function | Recommendation |
| Mild–Moderate impairment (eGFR 30–89 mL/min) | No dosage adjustment required |
| Severe impairment (eGFR <30 mL/min) | No dose adjustment; use with caution due to altered volume of distribution |
| Haemodialysis | No specific data; not significantly dialysed; dose as per clinical response |
HEPATIC ADJUSTMENT
| Child-Pugh Class | Score | Recommendation |
|
Class A (Mild)
|
5–6 points | No dose adjustment required |
|
Class B (Moderate)
|
7–9 points | No dose adjustment required; monitor closely for adverse effects |
|
Class C (Severe)
|
10–15 points | Use with caution; start at lower infusion rate; titrate cautiously; limited data available |
Clinical Notes:
- Isoproterenol is metabolised by catechol-O-methyltransferase (COMT) and is not primarily hepatically cleared
- Severe hepatic impairment may alter haemodynamic response — closer monitoring advised
CONTRAINDICATIONS
- Tachyarrhythmias (ventricular tachycardia, atrial fibrillation with rapid ventricular response, sinus tachycardia)
- Digitalis-induced ventricular arrhythmias
- Known hypersensitivity to isoproterenol or formulation components
- Pre-existing ventricular fibrillation
- Uncorrected hypokalaemia or hypomagnesaemia
CAUTIONS
- Hypertrophic obstructive cardiomyopathy (HOCM) — may worsen outflow obstruction
- Acute myocardial infarction or known coronary artery disease — may exacerbate ischaemia and increase infarct size
- Hyperthyroidism — enhanced sensitivity to catecholamines
- Hypovolaemia — ensure adequate volume resuscitation before initiation
- Diabetes mellitus — may cause hyperglycaemia
- Concurrent use with other sympathomimetics — increased arrhythmia risk
- Elderly patients with underlying cardiac disease
- Phaeochromocytoma (rare)
PREGNANCY
| Aspect | Details |
|
Overall safety
|
Limited human data; not formally assigned risk category; use only when clearly indicated |
|
When to use
|
Emergency situations (life-threatening bradycardia) where no safer alternatives are effective |
|
Preferred alternatives
|
Atropine (for vagal-mediated bradycardia); dopamine or dobutamine (for haemodynamic support) |
|
Monitoring required
|
Maternal: HR, BP, ECG. Fetal: Continuous fetal heart rate monitoring; assess uterine perfusion |
LACTATION
| Aspect | Details |
|
Compatibility
|
Likely compatible — short half-life, low systemic exposure with controlled infusion |
|
Expected levels in milk
|
Low (minimal transfer expected) |
|
Preferred alternatives
|
Based on indication; avoid routine outpatient use |
|
Infant monitoring
|
Irritability, tachycardia, feeding difficulties (though risk is low) |
ELDERLY
| Aspect | Recommendation |
|
Starting dose
|
0.01 mcg/kg/min IV (lower end of range) |
|
Titration
|
Slower titration advised — increase every 15–20 minutes rather than 10 minutes |
|
Extra risks
|
Reduced beta-receptor responsiveness; increased risk of tachyarrhythmias; underlying ischaemic heart disease may be unmasked; orthostatic hypotension due to peripheral vasodilation |
|
Monitoring
|
More frequent ECG and BP monitoring; watch for angina symptoms |
MAJOR DRUG INTERACTIONS
| Interacting Drug | Effect/Risk | Management |
|
MAO inhibitors (phenelzine, tranylcypromine, linezolid)
|
Severe potentiation of cardiovascular effects; risk of hypertensive crisis and arrhythmias | AVOID combination; if unavoidable, use significantly reduced doses with intensive monitoring |
|
Beta-blockers (propranolol, metoprolol, carvedilol)
|
Antagonistic effect — blunts isoproterenol response | Discontinue beta-blocker if isoproterenol therapy essential; select cardioselective agent if must continue |
|
Halogenated general anaesthetics (halothane, enflurane, isoflurane)
|
Increased risk of ventricular arrhythmias due to myocardial sensitisation to catecholamines | Avoid combination or use extreme caution; consider alternative anaesthetics |
|
Tricyclic antidepressants (amitriptyline, imipramine)
|
Potentiated cardiovascular effects | Avoid combination or use with extreme caution |
MODERATE DRUG INTERACTIONS
| Interacting Drug | Effect/Risk | Management |
|
Digoxin
|
Increased risk of arrhythmias (both drugs affect cardiac conduction) | Monitor ECG closely; watch for ectopic beats |
|
Diuretics (furosemide, thiazides)
|
Risk of hypokalaemia-induced arrhythmias | Monitor serum potassium; supplement as needed |
|
Corticosteroids (systemic)
|
May potentiate hypokalaemia | Monitor electrolytes with prolonged co-administration |
|
Other adrenergic agonists (adrenaline, dopamine, dobutamine)
|
Additive cardiovascular effects — risk of severe hypertension, tachycardia, arrhythmias | Avoid concurrent use if possible; if essential, use reduced doses with enhanced monitoring |
|
Theophylline/aminophylline
|
Additive cardiac stimulation | Monitor heart rate and rhythm |
COMMON ADVERSE EFFECTS
- Tachycardia (dose-related)
- Palpitations
- Headache
- Tremor
- Nervousness or anxiety
- Nausea
- Flushing
- Sweating
- Dizziness
SERIOUS ADVERSE EFFECTS
| Adverse Effect | Notes |
| Ventricular arrhythmias (VT/VF) | May require immediate drug cessation and antiarrhythmic therapy |
| Angina pectoris / Myocardial infarction | In patients with underlying CAD; discontinue immediately |
| Severe hypotension | Paradoxical effect due to peripheral β2-mediated vasodilation; may require volume support |
| Hypertensive crisis | Rare; if overdosed or with MAOIs |
| Severe hypokalaemia | Especially with high-dose or prolonged infusions; may precipitate arrhythmias |
| Pulmonary oedema | Rare; in patients with underlying cardiac dysfunction |
MONITORING REQUIREMENTS
| Timing | Parameters |
|
Baseline
|
12-lead ECG; serum electrolytes (K+, Mg2+); renal function; volume status assessment; cardiac history review |
|
During initiation/titration
|
Continuous ECG monitoring; blood pressure and heart rate every 5–15 minutes; SpO2; urine output |
|
During maintenance infusion
|
Continuous ECG; BP and HR hourly once stable; serum potassium every 6–12 hours in prolonged infusions |
|
Long-term (ICU settings)
|
Monitor for tachyphylaxis; daily electrolytes; assess need for weaning; evaluate for definitive therapy (pacing) |
BRANDS AVAILABLE IN INDIA
- Isolin (Neon Laboratories)
- Isuprel (generic availability)
- Isoprenaline Injection IP (various manufacturers)
Note: Availability may be limited to hospital pharmacy or ICU stock; not routinely stocked in retail pharmacies.
PRICE RANGE (INR)
| Formulation | Price Range | Notes |
| 0.2 mg/mL (1 mL ampoule) | ₹30–₹70 per ampoule | Brand-dependent |
| 1 mg/5 mL vial | ₹100–₹200 per vial | Less commonly stocked |
- Not listed in NLEM India
- Price not NPPA-regulated
- Primarily available through hospital/institutional supply
CLINICAL PEARLS
- Temporising agent only — Isoproterenol is a bridge therapy for symptomatic bradycardia while definitive treatment (transvenous pacing) is arranged; never use as long-term solution.
- Avoid in ischaemic heart disease — Increases myocardial oxygen demand due to positive chronotropic and inotropic effects; can precipitate angina or extend infarct size.
- Titrate slowly and monitor closely — Start at lowest dose and increase gradually; tachyarrhythmias are dose-dependent and may occur even at therapeutic doses.
- Useful in Torsades when pacing unavailable — Increasing heart rate to 90–110 bpm shortens QT interval and suppresses pause-dependent arrhythmias; however, magnesium remains first-line.
- Ensure adequate volume status — Peripheral β2-mediated vasodilation can cause paradoxical hypotension if patient is hypovolaemic; fluid resuscitation before initiation.
- Watch for hypokalaemia — β2-stimulation drives potassium intracellularly; monitor and supplement potassium during prolonged infusions to prevent arrhythmias.
TAGS
isoproterenol; isoprenaline; bradycardia; beta-agonist; ACLS; ICU; arrhythmia; torsades de pointes; cardiac pacing bridge; paediatric cardiac; Schedule H
VERSION
RxIndia v0.9 — 28 Feb 2026
REFERENCES
- CDSCO approved product information
- Indian Pharmacopoeia / National Formulary of India
- AIIMS Paediatric and Adult Emergency Protocols
- Indian Society of Critical Care Medicine (ISCCM) practice recommendations
- API Textbook of Medicine — Arrhythmia Management
- Goodman & Gilman’s The Pharmacological Basis of Therapeutics
- American Heart Association ACLS Guidelines (supportive — for off-label indications)
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Clinical Responsibility
This platform is designed strictly for healthcare professionals. Data provided is synthesized from authoritative pharmacological sources and clinical registries. Do not use for consumer medical decisions. Always verify critical dosing and contraindications with official institutional protocols and peer-reviewed journals.
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