What is the recommended dosing for labetalol (labetalol) in the management of hypertension?

Labetalol Dosing for Hypertension

Oral Dosing for Chronic Hypertension Management

For chronic hypertension, initiate labetalol at 100 mg twice daily, titrating upward by 100 mg twice daily every 2-3 days based on standing blood pressure, with usual maintenance doses of 200-400 mg twice daily and a maximum of 2,400 mg daily if needed. 1

Initial Dosing and Titration

• Start with 100 mg twice daily, whether used alone or added to a diuretic 1
• The full antihypertensive effect occurs within 1-3 hours of each dose, allowing office-based assessment of tolerability 1
• Increase by 100 mg twice daily every 2-3 days using standing blood pressure as the indicator 1
• Measure antihypertensive effects at follow-up visits approximately 12 hours after dosing to determine if further titration is necessary 1

Maintenance and Maximum Dosing

• Usual maintenance range: 200-400 mg twice daily 1
• Severe hypertension may require 1,200-2,400 mg daily, with or without thiazide diuretics 1
• If side effects (nausea, dizziness) occur with twice-daily dosing, divide the same total daily dose into three times daily to improve tolerability 1
• Do not exceed 200 mg increments when titrating twice-daily dosing 1

Special Population: Elderly Patients

• Initiate at 100 mg twice daily and titrate upward in 100 mg increments as needed 1
• Elderly patients eliminate labetalol more slowly and may achieve adequate control at lower maintenance doses 1
• Most elderly patients require only 100-200 mg twice daily 1

Combination Therapy Considerations

• When adding a diuretic, expect an additive antihypertensive effect that may necessitate labetalol dose reduction 1
• Optimal doses are usually lower in patients also receiving a diuretic 1
• When transferring from other antihypertensives, introduce labetalol as recommended while progressively decreasing the existing therapy 1

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Intravenous Dosing for Hypertensive Emergencies

For 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, or use a continuous infusion at 0.4-1.0 mg/kg/h (up to 3 mg/kg/h). 2

Acute Bolus Dosing Protocol

• Initial dose: 0.3-1.0 mg/kg (maximum 20 mg) slow IV injection every 10 minutes 2
• Maximum cumulative dose: 300 mg per treatment session 2
• May repeat the entire protocol every 4-6 hours as needed 2
• Do not exceed 300 mg cumulative dose when using repeated IV boluses without switching to infusion 3

Continuous Infusion Protocol

• Start at 0.4-1.0 mg/kg/h 2
• May titrate up to 3 mg/kg/h as needed 3
• Requires vigilant monitoring in the intensive care unit setting 4

Blood Pressure Targets in Emergencies

• General hypertensive emergencies: Reduce mean arterial pressure by 20-25% over several hours 3
• Acute ischemic stroke (not eligible for thrombolytics) with SBP >220 mmHg or DBP 121-140 mmHg: Aim for 10-15% reduction 2
• Acute ischemic stroke (eligible for thrombolytics) with SBP >185 mmHg or DBP >110 mmHg: Give 10-20 mg IV over 1-2 minutes, may repeat once 3, 2
• Acute hemorrhagic stroke: Target SBP <180 mmHg 3
• Acute aortic disease: Target SBP ≤120 mmHg and heart rate ≤60 bpm 3

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Special Clinical Scenarios

Severe Preeclampsia/Eclampsia

• First-line therapy with target SBP <160 mmHg and DBP <105 mmHg 3
• Initial dose: 20 mg IV bolus 2
• Follow with 40 mg after 10 minutes if needed 2
• Then 80 mg every 10 minutes for 2 additional doses 2
• Maximum cumulative dose: 220 mg (not to exceed 800 mg/24h to prevent fetal bradycardia) 3, 2
• Target: Decrease mean blood pressure by 15-25% with SBP 140-150 mmHg and DBP 90-100 mmHg 3

Stroke Management Monitoring

• For thrombolytic-eligible patients: Check blood pressure every 15 minutes for 2 hours, then every 30 minutes for 6 hours, then hourly for 16 hours 3, 2
• For acute hemorrhagic stroke: Monitor blood pressure every 15 minutes until stabilized for the first 24-48 hours 3

Pregnancy Considerations

• Labetalol is first-line for hypertension in pregnancy 2
• May require three or four times daily dosing due to accelerated drug metabolism during pregnancy 2
• May be less effective postpartum compared to calcium channel blockers with higher readmission risk 2

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Contraindications and Precautions

Absolute Contraindications

• Second or third-degree heart block 3, 2
• Bradycardia 3
• Decompensated heart failure 3, 2
• Reactive airways disease or COPD 3, 2

Clinical Advantages

• Particularly useful in hyperadrenergic states 3, 2
• Preferred in hypertensive encephalopathy as it leaves cerebral blood flow relatively intact 3
• Reduces afterload without increasing heart rate in acute coronary events, decreasing myocardial oxygen demand 3

Safety Considerations

• Onset of action: 1-2 minutes 3
• Prolonged infusions exceeding 300 mg/24h require vigilance with ready availability of glucagon, beta-agonists, phosphodiesterase inhibitors, insulin, and vasopressin for severe cardiovascular depression 4
• May worsen heart failure 2