What is the protocol for preparing a labetalol IV bolus?

Preparation of Labetalol IV Bolus

For intravenous labetalol bolus administration, prepare a solution by diluting the vial contents with commonly used intravenous fluids, with the standard initial dose being 20 mg (0.25 mg/kg for an 80 kg patient) administered by slow IV injection over 1-2 minutes. 1

Standard Preparation Methods

• Labetalol HCl injection is intended for intravenous use in hospitalized patients and must be administered with the patient in a supine position 1
• Two common preparation methods for continuous infusion include:
  • Adding 40 mL of labetalol (contents of two 20-mL vials or one 40-mL vial) to 160 mL of IV fluid to create a 1 mg/mL solution 1
  • Adding 40 mL of labetalol to 250 mL of IV fluid to create approximately a 2 mg/3 mL solution 1

IV Bolus Administration

• For bolus administration, the initial dose is 20 mg administered by slow IV injection over a 2-minute period 1
• Blood pressure should be measured immediately before injection and at 5 and 10 minutes after injection to evaluate response 1
• Additional injections of 40 mg or 80 mg can be given at 10-minute intervals until desired blood pressure is achieved or a total of 300 mg has been administered 1
• Maximum effect usually occurs within 5 minutes of each injection 1

Compatible IV Solutions

• Labetalol HCl injection is compatible with and stable for 24 hours (refrigerated or at room temperature) when mixed with: 1

  • Ringer's Injection, USP
  • Lactated Ringer's Injection, USP
  • 5% Dextrose Injection, USP
  • 0.9% Sodium Chloride Injection, USP
  • Various combinations of dextrose and sodium chloride solutions

• Labetalol is NOT compatible with 5% Sodium Bicarbonate Injection, USP 1

Clinical Considerations

• Blood pressure should be monitored during and after completion of IV injections 1
• Rapid or excessive falls in either systolic or diastolic blood pressure should be avoided 1
• The American Heart Association recommends an initial dose of 0.3-1.0 mg/kg (maximum 20 mg) by slow IV injection every 10 minutes, with a maximum cumulative dose of 300 mg 2, 3
• For hypertensive emergencies, labetalol is particularly useful in hyperadrenergic states 3, 4

Contraindications and Precautions

• Labetalol is contraindicated in patients with: 3, 4

  • Reactive airways disease or chronic obstructive pulmonary disease
  • Second or third-degree heart block or bradycardia
  • Decompensated heart failure

• Patients should always be kept in a supine position during administration as substantial fall in blood pressure on standing should be expected 1

Monitoring Parameters

• Monitor blood pressure immediately before injection, at 5 minutes, and at 10 minutes after injection 1
• For patients receiving thrombolytic therapy, check blood pressure every 15 minutes for 2 hours, then every 30 minutes for 6 hours, and finally every hour for 16 hours 5

Labetalol's onset of action is 1-2 minutes with peak effect within 5 minutes of each injection, making it suitable for rapid but controlled blood pressure reduction in emergency situations 1, 6.