Labetalol
Non-Selective Beta-Blocker with Alpha-1 Blocking Activity
Generic Name
Labetalol
Drug Class
Non-selective beta-adrenergic blocker with alpha-1 blocking activity
Indications
- Hypertension (including hypertensive emergencies)
- Preeclampsia/eclampsia (blood pressure control)
- Chronic heart failure (selected cases)
Dosage
- Hypertension (oral, adults): 100 mg twice daily initially; may titrate to 200–400 mg/day
- Hypertensive emergency (IV): 20 mg IV over 2 minutes; may repeat or continuous infusion 1–2 mg/min
- Preeclampsia (IV): 20 mg IV bolus, repeat 40 mg after 10 min if needed; infusion 1–2 mg/min
- Children: Use under specialist guidance; dose individualized
Note: Adjust dose in hepatic impairment; monitor blood pressure and heart rate.
Route of Administration
Oral (tablet), Intravenous
Mechanism of Action
Labetalol blocks beta-1 and beta-2 adrenergic receptors, reducing heart rate and myocardial contractility. Alpha-1 blockade causes vasodilation, reducing systemic vascular resistance and blood pressure.
Common Adverse Effects
- Dizziness
- Fatigue
- Bradycardia
- Orthostatic hypotension
- Headache
Serious Adverse Effects
- Severe bradycardia or AV block
- Heart failure exacerbation
- Severe hypotension
- Bronchospasm in asthma/COPD patients
Contraindications
- Asthma with bronchospasm
- Second- or third-degree AV block
- Severe bradycardia
- Cardiogenic shock
- Hypersensitivity to labetalol
Precautions
- Monitor heart rate, blood pressure, and cardiac status
- Use caution in diabetes; may mask hypoglycemia
- Gradually taper if discontinuing therapy
- Adjust dose in hepatic impairment
Drug Interactions
- Other antihypertensives – additive hypotensive effect
- Antiarrhythmics – increased risk of bradycardia or AV block
- Insulin or oral hypoglycemics – may mask hypoglycemia
- CYP2D6 inhibitors – may increase labetalol plasma levels
Pregnancy & Lactation
Preferred for blood pressure control in pregnancy when indicated. Use caution in breastfeeding; monitor infant for bradycardia or hypotension.
Patient Counseling
- Take with or immediately after meals to improve absorption
- Do not stop abruptly; taper gradually
- Monitor heart rate and blood pressure
- Report dizziness, fainting, or respiratory issues