Labetalol Uses, Dosage, Side Effects & Warnings | DrugsAtlas

• Tablets: 100 mg, 200 mg
• Injection: 5 mg/mL (20 mL ampoule = 100 mg per ampoule)

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INDICATIONS + DOSING — FOR CLINICIAN USE ONLY

• Key clinical notes:
• • Do not withdraw abruptly; taper over 1–2 weeks to avoid rebound hypertension and tachycardia
  • Oral bioavailability is approximately 25% due to extensive first-pass hepatic metabolism
  • Alpha-to-beta blockade ratio is approximately 1:3 (oral)

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• Key clinical notes:
• • IV onset: 2–5 minutes; peak effect: 5–15 minutes; duration: 2–4 hours (bolus)
  • Patient must remain supine during IV administration and for at least 3 hours after, to minimise postural hypotension
  • Continuous ECG and intra-arterial or frequent non-invasive BP monitoring mandatory
  • Alpha-to-beta blockade ratio is approximately 1:7 (IV)

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• If BP not controlled after 300 mg cumulative, switch to alternative agent (e.g. IV hydralazine, oral nifedipine) and reassess
• Once BP stabilised: transition to oral labetalol 100–200 mg every 8–12 hours
• Target: reduce systolic BP to 140–150 mmHg, diastolic to 90–100 mmHg (avoid precipitous fall)
• Monitor maternal heart rate, BP, urine output; fetal heart rate monitoring throughout

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PAEDIATRIC DOSING (Specialist Only)

• Continuous ECG and BP monitoring mandatory
• Must be administered in ICU or high-dependency setting

• Safety monitoring: Heart rate, blood pressure, blood glucose (especially in neonates/infants), hepatic function at baseline and periodically
• Minimum age: Generally ≥1 year for standard use; neonatal use only under paediatric cardiologist/nephrologist supervision in NICU

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RENAL ADJUSTMENT

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HEPATIC ADJUSTMENT

• Labetalol undergoes extensive first-pass hepatic metabolism; bioavailability may increase substantially in hepatic dysfunction
• Cases of severe hepatocellular injury (including fatalities) have been reported — discontinue immediately if signs of hepatic injury develop

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CONTRAINDICATIONS

• Bronchial asthma or documented history of bronchospasm
• Severe sinus bradycardia (<50 bpm)
• Second- or third-degree atrioventricular block (without functioning pacemaker)
• Cardiogenic shock
• Decompensated (uncontrolled) heart failure
• Pheochromocytoma without prior adequate alpha-adrenergic blockade (risk of paradoxical hypertensive crisis)
• Known hypersensitivity to labetalol or any excipient
• Known history of labetalol-associated hepatotoxicity

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CAUTIONS

• Diabetes mellitus — may mask tachycardia and other adrenergic symptoms of hypoglycaemia; blood glucose monitoring essential
• Chronic obstructive pulmonary disease (COPD) — use with extreme caution; preferably under respiratory monitoring
• Peripheral vascular disease — may worsen symptoms
• Hepatic dysfunction — increased bioavailability and hepatotoxicity risk (see Hepatic Adjustment)
• Older adults — increased risk of postural hypotension, falls, syncope (see Elderly section)
• Concurrent general anaesthesia — inform anaesthetist; additive bradycardia and hypotension
• First-dose orthostatic hypotension — especially with IV use; ensure patient is supine
• History of severe anaphylaxis — beta-blockers may reduce effectiveness of adrenaline in anaphylaxis management
• Prinzmetal (vasospastic) angina — beta-blockade may worsen coronary vasospasm

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PREGNANCY

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LACTATION

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ELDERLY

• Recommended starting dose: 100 mg once daily (or twice daily if tolerated)
• Titration: Slower than in younger adults; increase at intervals of no less than 3–5 days
• Extra risks:
• • Postural hypotension and syncope — assess standing BP before and after dose changes
  • Falls and related fractures
  • Reduced renal reserve — monitor renal function
  • Blunted compensatory tachycardia — higher risk of symptomatic bradycardia
  • Masked hypoglycaemia in elderly diabetics
• Monitoring: Postural BP, heart rate, renal function, blood glucose (if diabetic)

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MAJOR DRUG INTERACTIONS

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MODERATE DRUG INTERACTIONS

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COMMON ADVERSE EFFECTS

• Postural hypotension (especially first dose and with IV use)
• Dizziness
• Fatigue / tiredness
• Nausea
• Scalp tingling (paraesthesia)
• Nasal congestion
• Headache

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SERIOUS ADVERSE EFFECTS

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MONITORING REQUIREMENTS

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BRANDS AVAILABLE IN INDIA

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PRICE RANGE (INR)

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CLINICAL PEARLS

1. First-line IV agent for pregnancy-related hypertensive emergencies in Indian hospitals — the escalating bolus protocol (20 → 40 → 80 → 80 → 80 mg; max 300 mg) is the standard of care per ICMR/FOGSI guidelines.
2. Absolutely avoid in asthma — even the alpha-blocking component does not provide sufficient bronchodilatory protection; the beta-blockade is non-selective and can trigger severe, refractory bronchospasm.
3. Do not use alone in pheochromocytoma — unopposed alpha-stimulation can occur despite the alpha-blocking property; always ensure adequate alpha-blockade (e.g., phenoxybenzamine) is established first.
4. Orthostatic hypotension is the most common cause of patient distress — counsel on rising slowly from sitting/lying positions; particularly relevant in elderly and postpartum patients.
5. Hepatotoxicity, though rare, can be fatal — obtain baseline LFTs; have a low threshold for re-checking if the patient develops malaise, anorexia, dark urine, or jaundice; do not re-challenge after confirmed hepatic injury.
6. IV to oral transition: once BP is stabilised with IV labetalol, switch to oral 100–200 mg every 8–12 hours. Oral alpha-to-beta blockade ratio (1:3) differs from IV (1:7) — anticipate different haemodynamic profile with route change.

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TAGS

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VERSION

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REFERENCES

• CDSCO-approved prescribing information for labetalol
• Indian Pharmacopoeia
• National List of Essential Medicines (NLEM) 2022, Ministry of Health & Family Welfare, Government of India
• API Textbook of Medicine
• ICMR Guidelines on Management of Hypertension in Pregnancy
• FOGSI Good Clinical Practice Recommendations — Hypertensive Disorders of Pregnancy
• AIIMS Hypertension and Emergency Medicine Protocols
• IAP Guidelines on Paediatric Hypertension
• Indian PICU / Paediatric Hypertension Protocols
• WHO Guidelines on Management of Severe Hypertension in Pregnancy (supportive reference)
• Goodman & Gilman's The Pharmacological Basis of Therapeutics (pharmacology reference)