Labetalol is a 3rd-generation beta-blocker with combined β1, β2, and alpha-1 blockade.
It reduces heart rate and systemic vascular resistance, making it particularly useful in acute blood pressure control.
Classification: • 3rd Generation (Vasodilating) • Nonselective beta-blocker • Alpha-1 blockade • No intrinsic sympathomimetic activity (ISA)
Blocks:
• β1 receptors → ↓ Heart rate, ↓ contractility • β2 receptors → Potential bronchospasm • Alpha-1 receptors → Vasodilation (↓ SVR)
Net Effects:
• ↓ Cardiac output • ↓ Systemic vascular resistance • ↓ Blood pressure
Unlike pure beta-blockers, labetalol reduces SVR without causing reflex tachycardia.
• Common IV agent • Rapid BP reduction • Frequently used in stroke and aortic dissection
• Oral option for controlled BP lowering
• First-line agent in pregnancy • Safe in preeclampsia
• Not first-line for uncomplicated HTN • Consider when alpha blockade is beneficial
IV Labetalol: • Used in hypertensive emergencies • Rapid onset
Oral Labetalol: • Used in pregnancy-related hypertension • Used in resistant hypertension
• Hypotension • Bradycardia • Dizziness • Orthostatic hypotension • Bronchospasm (β2 blockade)
• Severe bradycardia • High-grade AV block (without pacemaker) • Cardiogenic shock • Acute decompensated heart failure
Use caution in: • Asthma • Severe hypotension
Both block β1, β2, and alpha-1 receptors.
Carvedilol: • Mortality benefit in HFrEF • Primarily chronic outpatient use
Labetalol: • Preferred for acute BP control • Preferred in pregnancy • Not a core HFrEF mortality agent
✔ Combined alpha and beta blockade ✔ Excellent for hypertensive emergency ✔ First-line for hypertension in pregnancy ✔ IV formulation commonly used in hospital ✔ Not one of the HFrEF mortality-reducing agents
Related:
→ Beta-Blockers Overview → Hypertension Module → Heart Failure Module → Return to Cardiovascular Modules