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)

→ Beta-Blockers Overview

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

→ Hypertension Module

• 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