Labetalol

• Gestational hypertension (≥140/90)
• Chronic HTN in pregnancy
• Pre-eclampsia BP control
• Acute severe HTN (≥160/110)

Blocks α1 (vasodilation) + β1/β2 (prevents reflex tachycardia). Ratio 3:1 oral, 7:1 IV — IV is more β-dominant.

• A — Asthma (absolute CI, β2 bronchospasm)
• B — Bradycardia / Block (2°/3°)
• C — Cardiogenic shock / severe HF
• D — Don’t mix with Verapamil/Diltiazem
• E — Epidural → watch BP drop

Oral start

100 mg BD

Oral max

2,400 mg/day (3–4 divided)

IV bolus

50 mg over 2 min → 100 mg → max 200 mg

IV infusion

20 mg/h, double q30 min, max 160 mg/h

• AbsoluteAsthma / reactive airway disease
• Absolute2°/3° heart block, severe bradycardia
• AbsoluteCardiogenic shock, severe HF

• Scalp tingling (classic α effect)
• Postural hypotension
• Fatigue, dizziness, headache
• Nasal congestion
• Mild ↑ LFTs (rare severe hepatotoxicity)

• • Not teratogenic — safe T2/T3 initiation.
• • Minor FGR risk (less than atenolol). Growth scans q4 weeks.
• • Neonate: monitor glucose + HR for 24–48 h (hypoglycaemia, bradycardia).

• IV MgSO₄

  Caution

  Enhanced hypotension — BP q5–15 min

• Verapamil / Diltiazem

  Avoid

  Severe bradycardia & block — do NOT combine

• Nifedipine

  OK

  Safe & commonly combined in resistant HTN

• Salbutamol (β2 agonist)

  Avoid

  Antagonised — bronchospasm risk

• NSAIDs

  Caution

  ↓ antihypertensive efficacy

• 💡 Always document: “Any history of asthma or inhaler use?” before prescribing.
• 💡 Bioavailability rises with food and in pregnancy — needs dose escalation as pregnancy advances.
• 💡 NICE target BP <135/85 mmHg.