What is the dose of labetalol (alpha- and beta-adrenergic blocker) infusion?

From the Guidelines

Labetalol infusion for hypertensive emergencies should be initiated at a dose of 0.4-1.0-mg/kg/h IV infusion up to 3 mg/kg/h, with adjustments made to achieve the desired blood pressure response, as recommended by the 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA guideline 1. The dose of labetalol infusion can be adjusted up to a total cumulative dose of 300 mg, and this dose can be repeated every 4-6 hours as needed.

• The infusion is typically prepared by adding 200-300 mg of labetalol to 250 mL of compatible IV fluid, resulting in a concentration of 1 mg/mL.
• Blood pressure should be monitored every 5-10 minutes during initial titration, with the goal of reducing mean arterial pressure by no more than 25% in the first hour.
• Labetalol works as a combined alpha and beta-adrenergic blocker, with the beta-blocking effect being approximately 7 times stronger than its alpha-blocking effect, which helps reduce blood pressure while maintaining cardiac output.
• Patients should be monitored for bradycardia, hypotension, and bronchospasm during administration, and labetalol is contraindicated in patients with severe bradycardia, heart block greater than first degree, cardiogenic shock, and severe bronchospastic disease. Key considerations for labetalol infusion include:
• Initial dose: 0.4-1.0-mg/kg/h IV infusion
• Maximum dose: 3 mg/kg/h
• Total cumulative dose: 300 mg
• Repeat dose: every 4-6 hours as needed
• Monitoring: blood pressure every 5-10 minutes during initial titration
• Contraindications: severe bradycardia, heart block greater than first degree, cardiogenic shock, and severe bronchospastic disease.

From the FDA Drug Label

DOSAGE AND ADMINISTRATION Labetalol HCl Injection is intended for intravenous use in hospitalized patients. DOSAGE MUST BE INDIVIDUALIZED depending upon the severity of hypertension and the response of the patient during dosing. Slow Continuous Infusion Labetalol HCl Injection is prepared for continuous intravenous infusion by diluting the vial contents with commonly used intravenous fluids (see below) Examples of two methods of preparing the infusion solution are: The contents of either two 20-mL vials (40 mL), or one 40-mL vial, are added to 160 mL of a commonly used intravenous fluid such that the resultant 200 mL of solution contains 200 mg of labetalol HCl, 1 mg/mL. The diluted solution should be administered at a rate of 2 mL/min to deliver 2 mg/min The rate of infusion of the diluted solution may be adjusted according to the blood pressure response, at the discretion of the physician.

The dose of labetalol infusion is individualized and depends on the severity of hypertension and the patient's response. The infusion can be prepared by diluting the vial contents with intravenous fluids, and the rate of infusion can be adjusted according to blood pressure response. The effective intravenous dose is usually in the range of 50 to 200 mg, and the infusion should be continued until a satisfactory response is obtained. 2

From the Research

Dose of Labetalol Infusion

• The dose of labetalol infusion can vary depending on the patient's condition and the severity of hypertension.
• According to a study published in 1985 3, labetalol was injected at a dose of 0.25 mg/kg body weight, followed by repeat injections of 0.5 mg/kg every 15 minutes until the supine diastolic blood pressure was reduced to less than 90 mm Hg or a total of 3.25 mg/kg had been administered.
• Another study published in 1985 4 evaluated the antihypertensive effects of labetalol infusion at a rate of 2 mg/min, with a maximal dose of 150 mg.
• A more recent study published in 2018 5 compared the safety and efficacy of continuous-infusion labetalol with continuous-infusion nicardipine in patients with acute stroke, but did not specify the exact dose of labetalol used.
• A study published in 2014 6 compared the safety and efficacy of labetalol and nicardipine in patients with renal dysfunction, using the FDA-recommended doses of each medication, but did not provide specific details on the dosing regimen of labetalol.

Administration and Monitoring

• Labetalol infusion should be administered with caution and closely monitored, as it can cause significant reductions in blood pressure 3, 4.
• The infusion rate and dose of labetalol may need to be adjusted based on the patient's response to treatment and their individual characteristics, such as renal function 6.
• Patients receiving labetalol infusion should be closely monitored for signs of hypotension, bradycardia, and other adverse effects 7, 5.