cardio:beta_blockers:labetalol []

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====== Labetalol ======

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)

→ [[cardio:beta_blockers:start|Beta-Blockers Overview]]

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===== Mechanism of Action =====

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.

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===== Indications =====

==== Hypertensive Emergency ★ ====

• Common IV agent
• Rapid BP reduction
• Frequently used in stroke and aortic dissection

→ [[cardio:hypertension:start|Hypertension Module]]

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==== Hypertensive Urgency ====

• Oral option for controlled BP lowering

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==== Pregnancy-Induced Hypertension ★ ====

• First-line agent in pregnancy
• Safe in preeclampsia

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==== Chronic Hypertension ====

• Not first-line for uncomplicated HTN
• Consider when alpha blockade is beneficial

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===== IV vs Oral Use =====

IV Labetalol:
• Used in hypertensive emergencies
• Rapid onset

Oral Labetalol:
• Used in pregnancy-related hypertension
• Used in resistant hypertension

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===== Adverse Effects =====

• Hypotension
• Bradycardia
• Dizziness
• Orthostatic hypotension
• Bronchospasm (β2 blockade)

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===== Contraindications =====

• Severe bradycardia
• High-grade AV block (without pacemaker)
• Cardiogenic shock
• Acute decompensated heart failure

Use caution in:
• Asthma
• Severe hypotension

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===== Labetalol vs Carvedilol =====

Both block β1, β2, and alpha-1 receptors.

[[cardio:beta_blockers:carvedilol|Carvedilol]]:
• Mortality benefit in HFrEF
• Primarily chronic outpatient use

Labetalol:
• Preferred for acute BP control
• Preferred in pregnancy
• Not a core HFrEF mortality agent

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===== Clinical Pearls =====

✔ 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  

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Related:

→ [[cardio:beta_blockers:start|Beta-Blockers Overview]]
→ [[cardio:hypertension:start|Hypertension Module]]
→ [[cardio:heart_failure:start|Heart Failure Module]]
→ [[cardio:intro:start|Return to Cardiovascular Modules]]