Labetalol is a prescription medication classified as both a non-selective beta-adrenergic blocker and a selective alpha-1 adrenergic blocker. It is primarily used to treat high blood pressure (hypertension), including severe hypertension and hypertensive emergencies.
Pharmacological Classification:
- Alpha-1 adrenergic blocker
- Non-selective beta blocker (blocks both β1 and β2 receptors)
Mechanism of Action:
Labetalol works by:
- Blocking β1 receptors in the heart: decreases heart rate and contractility.
- Blocking β2 receptors in the lungs and blood vessels: reduces peripheral resistance.
- Blocking α1 receptors in blood vessels: causes vasodilation, reducing blood pressure.
Clinical Uses: Chronic hypertension, Hypertensive emergencies (IV form), Hypertension in pregnancy, including preeclampsia/eclampsia, Sometimes used for hypertensive crisis due to pheochromocytoma
Dosage Forms: Oral tablets, Intravenous (IV) injection
Common Side Effects: Dizziness, Fatigue, Orthostatic hypotension, Bradycardia, Nausea
Contraindications: Asthma or other bronchospastic conditions, Severe bradycardia or heart block, Overt cardiac failure