What is the dose of labetalol (Normodyne) 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.

Key Considerations

• The initial dose can be administered as a slow IV injection of 0.3–1.0-mg/kg dose (maximum 20 mg) every 10 min, or as an IV infusion, with a total cumulative dose not exceeding 300 mg 1.
• The infusion rate should be adjusted based on the patient's blood pressure response, with careful monitoring to avoid excessive hypotension.
• Labetalol's unique mechanism of combined alpha 1 and nonselective beta receptor antagonism provides balanced vasodilation and heart rate control, making it a valuable option for managing hypertensive emergencies.

Important Safety Information

• Common side effects of labetalol infusion include hypotension, bradycardia, and bronchospasm, and it should be used with caution in patients with heart failure, bradycardia, heart block, asthma, or COPD.
• Once blood pressure is stabilized, consideration should be given to transitioning to oral antihypertensive therapy.
• Labetalol is particularly useful in hypertensive emergencies associated with pregnancy, such as preeclampsia, due to its favorable safety profile 1.

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. The diluted solution should be administered at a rate of 2 mL/min to deliver 2 mg/min Alternatively, the contents of either two 20-mL vials (40 mL), or one 40-mL vial, of labetalol HCl injection are added to 250 mL of a commonly used intravenous fluid. The resultant solution will contain 200 mg of labetalol HCl, approximately 2 mg/3 mL. The diluted solution should be administered at a rate of 3 mL/min to deliver approximately 2 mg/min The effective intravenous dose is usually in the range of 50 to 200 mg A total dose of up to 300 mg may be required in some patients.

The dose of labetalol infusion is usually in the range of 50 to 200 mg, and it should be administered at a rate of 2 mg/min. The infusion rate can be adjusted according to the blood pressure response. A total dose of up to 300 mg may be required in some patients 2.

From the Research

Dose of Labetalol Infusion

• The dose of labetalol infusion can vary depending on the clinical setting and the patient's response to the medication 3.
• In one study, the antihypertensive effects of labetalol infusion were evaluated at a dose of 2 mg/min, with a maximal dose of 150 mg 3.
• Another study found that the maximum recommended dose of labetalol in any clinical setting is 300 mg in 24 hours, but higher doses may be safe and effective in certain situations 4.
• The safety of administering high doses of intravenous labetalol (greater than 300 mg in 24 hours) was evaluated in neurosurgical patients, with a mean dose of 623 +/- 86 mg given during 15 distinct periods of 24 hours or less 4.
• Continuous infusions of labetalol may exceed the recommended maximum daily dose of 300 mg on occasion, and prolonged administration in the intensive care unit requires vigilance and the establishment of a therapeutic rationale/policy for interventions 5.

Comparison with Other Antihypertensives

• Labetalol and nicardipine are antihypertensives commonly used in the management of elevated blood pressure, but there is limited evidence to suggest which agent should be used preferentially in certain settings 6.
• A study compared the safety, efficacy, and ease of administration of continuous-infusion labetalol with continuous-infusion nicardipine in patients with acute stroke, and found that the two agents were comparable in terms of time at goal blood pressure and blood pressure variability 6.
• Another study compared intravenous labetalol with intravenous nicardipine in the management of hypertension in critically ill patients, and found that nicardipine was associated with fewer adverse effects, including hypotension and bradycardia or atrioventricular block 7.

Clinical Outcomes and Costs

• The short-term clinical outcomes and costs of intravenous labetalol or intravenous nicardipine in the management of hypertension in critically ill patients were evaluated in a retrospective analysis, and found that there were no significant differences in the magnitude of the average change in systolic or diastolic blood pressure between the two agents 7.
• The proportion of patients achieving their blood pressure targets was significantly greater with nicardipine than with labetalol, and the proportion of patients requiring an alternate antihypertensive agent was significantly greater with labetalol than with nicardipine 7.
• The total number of all-cause adverse events was significantly greater with labetalol than with nicardipine, and the median hospital costs were not significantly different between patients receiving labetalol and patients receiving nicardipine 7.