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Combined alpha and beta blocker Pregnancy: Safe in pregnancy (most studied IV antihypertensive for eclampsia/pre-eclampsia). Watch for neonatal bradycardia.

Labetalol (IV — Hypertensive Emergency)

Brand names: Trandate

Adult dose

Dose: 50 mg IV bolus over 1 minute; or 2 mg/min infusion, titrated to response
Route: IV bolus or IV infusion
Frequency: Bolus: every 5 min (max 3 doses); infusion: continuous, titrated
Max: 200 mg bolus (total); infusion rate titrated to BP
Hypertensive emergency: 50 mg IV over 1 min; repeat every 5 min (max 200 mg). Then infusion 2–4 mg/min. Target: gradual BP reduction (avoid >25% reduction in first hour). Hypertensive urgency in pregnancy (eclampsia): 20 mg IV boluses (pre-eclampsia protocol). Also available as 100–400 mg oral BD.

Paediatric dose

Dose: 0.2 mg/kg
Route: IV
Frequency: Every 10 minutes if needed
Max: 1 mg/kg/dose (max 40 mg)
Concentration: 5 mg/ml
Hypertensive emergency (specialist): 0.2–1 mg/kg IV slowly. Max 40 mg/dose. Infusion: 0.4–3 mg/kg/hour. Paediatric hypertensive emergency — specialist input essential.

Dose adjustments

Renal

No dose adjustment required.

Hepatic

Reduce dose in severe hepatic impairment.

Paediatric weight-based calculator

Hypertensive emergency (specialist): 0.2–1 mg/kg IV slowly. Max 40 mg/dose. Infusion: 0.4–3 mg/kg/hour. Paediatric hypertensive emergency — specialist input essential.

Clinical pearls

  • Preferred for aortic dissection (reduces HR and BP simultaneously)
  • Avoid in cocaine-induced hypertension — use benzodiazepines or phentolamine instead
  • Alpha:Beta blockade ratio 1:7 (IV); allows use in situations where pure beta-blockade problematic
  • Eclampsia: IV labetalol first-line for acute hypertension in pregnancy (alongside nifedipine and hydralazine)

Contraindications

  • Asthma (combined beta-blockade)
  • Severe bradycardia
  • Second/third degree heart block
  • Decompensated heart failure
  • Cocaine-induced hypertension (paradoxical — beta-blockade leaves alpha unopposed)

Side effects

  • Hypotension
  • Bradycardia
  • Bronchospasm
  • Dizziness
  • Nausea

Interactions

  • Calcium channel blockers (verapamil, diltiazem) — severe bradycardia and heart failure risk
  • Anaesthetic agents — additive hypotension
  • GTN/nitrates — additive hypotension

Monitoring

  • BP every 5 min during titration
  • HR
  • Respiratory status
  • Blood glucose (if diabetic)

Reference: BNFc; BNF; NICE NG133 Hypertension in Pregnancy; ESC Hypertension Guidelines. Verify against your local formulary and the latest BNF before prescribing.

Related

Curated clinical cross-links plus same-class fallbacks.

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