Combined Alpha-1 and Beta-Adrenergic Blocker

Labetalol (IV — Hypertensive Emergency)

Brand names: Trandate

Used in: Pre-eclampsia & Obstetric Emergencies

Labetalol is a combined alpha- and beta-blocker used for hypertension — notably in pregnancy (first-line) and, intravenously, for hypertensive emergencies.

Dosing — being independently re-sourced

ClinCalc Pro is rebuilding its dose data from primary open sources — the manufacturer SmPC (eMC), the WHO Model Formulary and other official references — under clinician review. This drug's structured dose is not yet published here. Confirm all doses against the product SmPC and your local formulary before prescribing.

US labelling (FDA)

Reference — US labelling, may differ from UK

DOSAGE AND ADMINISTRATION DOSAGE MUST BE INDIVIDUALIZED. The recommended initial dosage is 100 mg twice daily whether used alone or added to a diuretic regimen. After 2 or 3 days, using standing blood pressure as an indicator, dosage may be titrated in increments of 100 mg b.i.d.(twice daily) every 2 or 3 days. The usual maintenance dosage of labetalol hydrochloride tablets is between 200 mg and 400 mg twice daily. Since the full antihypertensive effect of labetalol hydrochloride tablets is usually seen within the first 1 to 3 hours of the initial dose or dose increment, the assurance of a lack of an exaggerated hypotensive response can be clinically established in the office setting. The …

Source: US FDA prescribing information (openFDA / DailyMed), label dated 2026-05-22. Accessed 2026-06-12. US dosing and indications can differ from UK practice — use UK sources for prescribing decisions.

Clinical monograph

How it works

It blocks alpha-1 and beta adrenoceptors, lowering blood pressure through reduced vascular resistance and cardiac effects.

Prescribing in practice

It is first-line for hypertension in pregnancy and for many hypertensive emergencies; intravenous use requires close blood-pressure monitoring.
Avoid in asthma (beta-blockade can cause bronchospasm).
Postural hypotension can occur; rare hepatotoxicity is reported.

Monitoring

Monitor blood pressure (and the fetus in pregnancy where relevant); during IV use monitor closely.

Counselling the patient

Report wheeze or marked dizziness.
Take care standing up, especially early in treatment.

Evidence & guidelines

First-line for hypertension in pregnancy (NICE NG133) and used intravenously in hypertensive emergencies.

Reference: NICE NG133 (Hypertension in Pregnancy); ESC Aortic Diseases Guidelines 2014; MHRA SPC Trandate; AHA/ACC Hypertensive Crisis Guidelines 2017; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Calculators