What is the dosing frequency of labetalol for hypertension?

Labetalol Dosing Frequency for Hypertension

Intravenous Administration

For acute hypertensive emergencies, administer labetalol 10-20 mg IV over 1-2 minutes, repeating or doubling the dose every 10 minutes up to a maximum cumulative dose of 300 mg. 1

Bolus Dosing Protocol

• Initial dose: 10-20 mg IV push over 1-2 minutes 2, 1
• Repeat interval: Every 10 minutes 1
• Dose escalation: May repeat the same dose or double it with each administration 2, 1
• Maximum cumulative dose: 300 mg total 2, 1

Continuous Infusion Alternative

• Initial infusion rate: 2 mg/min (or 0.4-1.0 mg/kg/hour) 1
• Maximum infusion rate: Up to 3 mg/kg/hour 1
• Titration: Adjust based on blood pressure response every 5-15 minutes 1

Context-Specific IV Dosing

For acute ischemic stroke patients eligible for thrombolytics (BP >185/110 mmHg):

• Give 10-20 mg IV over 1-2 minutes 2, 1
• May repeat once after 10 minutes 1
• Goal: Maintain BP <185/110 mmHg 1

For acute ischemic stroke patients NOT eligible for thrombolytics (systolic >220 or diastolic 121-140 mmHg):

• Give 10-20 mg IV over 1-2 minutes 2
• Repeat or double every 10 minutes up to 300 mg maximum 2
• Goal: 10-15% reduction in blood pressure, not normalization 2, 1

For severe preeclampsia:

• Initial dose: 20 mg IV bolus 1
• Second dose: 40 mg after 10 minutes 1
• Third and fourth doses: 80 mg every 10 minutes for 2 additional doses 1
• Maximum cumulative dose: 220 mg (though up to 800 mg/24 hours has been used safely in pregnancy) 1

Oral Administration

For chronic hypertension management, start labetalol at 100 mg twice daily, titrating in increments of 100 mg twice daily every 2-3 days based on standing blood pressure response. 3

Oral Dosing Protocol

• Initial dose: 100 mg twice daily 3
• Titration interval: Every 2-3 days 3
• Titration increment: 100 mg twice daily 3
• Usual maintenance dose: 200-400 mg twice daily 3
• Maximum dose for severe hypertension: 1,200-2,400 mg per day (divided into 2-3 doses) 3

Timing Considerations for Oral Dosing

• The full antihypertensive effect occurs within 1-3 hours of each dose 3
• Assess blood pressure approximately 12 hours after a dose at follow-up visits to determine if further titration is needed 3
• If side effects (nausea, dizziness) occur with twice-daily dosing, divide the same total daily dose into three times daily 3

Elderly Patients

• Start at 100 mg twice daily 3
• Titrate upwards in 100 mg twice-daily increments as needed 3
• Most elderly patients achieve control with 100-200 mg twice daily (lower than general population due to slower elimination) 3

Monitoring Requirements

For patients receiving IV labetalol after thrombolytic therapy, check blood pressure every 15 minutes for 2 hours, then every 30 minutes for 6 hours, then hourly for 16 hours. 2, 1

General Monitoring

• During acute treatment: Every 15 minutes until stabilized 1
• Post-stabilization: Every 30 minutes for 6 hours, then hourly 2, 1

Critical Safety Points

Never exceed 300 mg cumulative dose when using repeated IV boluses without switching to continuous infusion. 1

Absolute Contraindications

• Second- or third-degree heart block 1
• Bradycardia 1
• Decompensated heart failure 1
• Reactive airways disease (asthma) or COPD 1

Blood Pressure Targets

• Aim for 10-15% reduction in mean arterial pressure for acute stroke 2, 1
• Target 20-25% reduction in mean arterial pressure over several hours for other hypertensive emergencies 1
• Avoid rapid normalization to prevent organ hypoperfusion 1