[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › [Beta blockers](https://durgical.com/en/pharmacology/classes/beta-blockers/) › Labetalol

[Pharmacology](https://durgical.com/en/pharmacology/) · [Beta blockers](https://durgical.com/en/pharmacology/classes/beta-blockers/)

# Labetalol

A combined α1 and β blocker, by mouth or IV. Used for severe hypertension and is a first choice for high blood pressure in pregnancy.

Updated 2026-11-01

- Class: [Beta blockers](https://durgical.com/en/pharmacology/classes/beta-blockers/)
- Receptor: β- and α1-adrenergic receptors
- ATC code: C07AG01

## ⚠ High-alert medication

An error with this medicine can cause serious harm: double checks and protocols are used.

◎**β- and α1-adrenergic receptors**Labetalol

ⓘ The figure shows carvedilol, another combined α1 and β blocker, in the human β2 receptor; no structure with labetalol bound is available.

**Target in 3D:** β- and α1-adrenergic receptors. PDB structure 6PS3 (RCSB PDB, public domain). [View the structure at RCSB PDB](https://www.rcsb.org/structure/6PS3) · Drag to rotate · pinch to zoom

## Mechanism of action

Labetalol blocks α1 receptors selectively and β1 and β2 receptors without selectivity, with stronger β than α block. α1 block dilates arterioles; β block prevents the reflex tachycardia that vasodilation would cause. Blood pressure falls with little change in heart rate and cardiac output, and falls more when standing than lying down.

- Labetalol blocks α1 receptors and β1/β2 receptors
- α1 block dilates arterioles and lowers resistance
- β block prevents reflex tachycardia

## Pharmacokinetics

**Absorption**
Large first-pass effect by mouth; liver disease raises its bioavailability

**Metabolism**
Liver, mainly by conjugation

**Half-life**
About 6 to 8 hours by mouth

## Indications

- Severe hypertension and hypertensive emergencies (IV) [Arterial hypertension →](https://durgical.com/en/conditions/arterial-hypertension/)
- High blood pressure in pregnancy, including pre-eclampsia [Preeclampsia →](https://durgical.com/en/conditions/preeclampsia/)

## Adverse effects

### Common

- Orthostatic hypotension and dizziness
- Tingling of the scalp
- Nausea
- Fatigue

### Serious (rare, important)

- Liver injury (rare)
- Bronchospasm
- Heart failure or heart block
- Marked hypotension after IV doses

## Contraindications

- Bronchial asthma or obstructive airway disease
- Overt heart failure or cardiogenic shock
- Heart block greater than first degree or severe bradycardia
- Conditions with severe and prolonged hypotension

## Key interactions

**Inhaled anaesthetics such as halothane**
Added lowering of blood pressure

**β2 agonist bronchodilators**
Labetalol blunts their bronchodilator effect

**Cimetidine**
Higher bioavailability of oral labetalol

## What is monitored

- Blood pressure and heart rate, lying and standing
- Continuous monitoring during IV use
- Liver tests if symptoms of liver injury appear
- Fetal heart rate in pregnancy

## Administration and safety

- IV doses are given with the patient lying down and continuous blood pressure monitoring
- After IV doses, the patient does not get up unassisted until standing blood pressure is checked
- Many «-olol» names look alike: the name and route are checked

## Nursing care

- Measure blood pressure often during IV dosing and report a sharp drop or bradycardia
- Help the patient up the first times; watch for orthostatic symptoms
- Ask about wheezing; teach the patient to report dark urine, jaundice or itching
- In pregnancy, monitor the mother's blood pressure and the fetal heart rate

## Pregnancy and breastfeeding

One of the preferred antihypertensives in pregnancy; low blood pressure, slow heart rate, low glucose and breathing depression have been reported in babies exposed before birth, so the newborn is watched.

## Memory aid

LABETalol is the LABor-and-pregnancy beta blocker: α to dilate, β to keep the pulse calm.

## Test yourself

Think of the answer, then tap the question to see it.

## Which receptors does labetalol block?

α1 receptors selectively plus β1 and β2 receptors, with stronger β block.

## Why does labetalol not cause reflex tachycardia like a pure vasodilator?

Its β block stops the heart from speeding up in response to the vasodilation from α1 block.

## Why is the patient kept lying down during IV labetalol?

Blood pressure falls more when standing, so standing up can cause marked orthostatic hypotension.

## Which antihypertensives are used in pregnancy, and which are contraindicated?

Used: labetalol and nifedipine (also methyldopa). Contraindicated: ACE inhibitors and ARBs.

[Add to my cards (4)](https://durgical.app/estudiar/?add=/en/pharmacology/labetalol/)

## Related drugs

- [Carvedilol](https://durgical.com/en/pharmacology/carvedilol/)
- [Esmolol](https://durgical.com/en/pharmacology/esmolol/)
- [Nifedipine](https://durgical.com/en/pharmacology/nifedipine/)

## Related conditions

- [Arterial hypertension](https://durgical.com/en/conditions/arterial-hypertension/)
- [Preeclampsia](https://durgical.com/en/conditions/preeclampsia/)

[← Back to the class: Beta blockers](https://durgical.com/en/pharmacology/classes/beta-blockers/)

Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: [DailyMed - LABETALOL HYDROCHLORIDE injection, solution](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=abfc6b75-1ed5-41f1-0484-4597488237bc) (DailyMed (U.S. National Library of Medicine), 2026); [ATCDDD - ATC/DDD Index](https://atcddd.fhi.no/atc_ddd_index/?code=C07AG01) (WHO Collaborating Centre for Drug Statistics Methodology, 2026); Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed., ch. 32 (McGraw Hill, 2023).

## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake

Representative model, for educational purposes only.

---
Source: https://durgical.com/en/pharmacology/labetalol/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/pharmacology/labetalol/