What is the dose of intravenous (IV) labetalol for tachycardia?

From the Guidelines

The dose of intravenous (IV) labetalol for tachycardia is 0.3-1.0 mg/kg (maximum 20 mg) slow IV injection every 10 min or 0.4-1.0 mg/kg/h IV infusion up to 3 mg/kg/h.

Key Points

• The initial dose can be repeated every 10 minutes as needed, with a maximum cumulative dose of 300 mg 1.
• The dose can also be adjusted by increasing the infusion rate up to 3 mg/kg/h 1.
• Labetalol is contraindicated in patients with reactive airways disease or chronic obstructive pulmonary disease, and should not be given to patients with second- or third-degree heart block or bradycardia 1.
• It is especially useful in hyperadrenergic syndromes, but may worsen heart failure 1.

Evidence Summary

The evidence from the American College of Cardiology/American Heart Association guidelines supports the use of labetalol for the treatment of tachycardia, with a recommended dose of 0.3-1.0 mg/kg (maximum 20 mg) slow IV injection every 10 min or 0.4-1.0 mg/kg/h IV infusion up to 3 mg/kg/h 1.

• The guidelines also provide information on the contraindications and precautions for the use of labetalol, including its potential to worsen heart failure and its contraindication in patients with reactive airways disease or chronic obstructive pulmonary disease 1.
• Additionally, the guidelines recommend adjusting the dose based on the patient's response, with a maximum cumulative dose of 300 mg 1.

From the FDA Drug Label

DOSAGE AND ADMINISTRATION Labetalol HCl Injection is intended for intravenous use in hospitalized patients. Either of two methods of administration of labetalol HCl injection may be used: a) repeated intravenous injections, b) slow continuous infusion Repeated Intravenous Injection Initially, labetalol HCl injection should be given in a dose of 20 mg labetalol HCl (which corresponds to 0. 25 mg/kg for an 80 kg patient) by slow intravenous injection over a 2-minute period. 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 intravenous (IV) labetalol for hypertension is usually in the range of 50 to 200 mg, with a total dose of up to 300 mg. However, the initial dose is 20 mg. For tachycardia, the FDA label does not provide a specific dose, but it can be inferred that the dose for tachycardia would be similar to that for hypertension.

• The initial dose is 20 mg.
• Additional doses of 40 mg or 80 mg can be given at 10-minute intervals.
• The maximum total dose is 300 mg. 2

From the Research

Dose of Intravenous Labetalol for Tachycardia

• The maximum recommended dose of intravenous labetalol in any clinical setting is 300 mg in 24 hours 3.
• However, studies have shown that higher doses of intravenous labetalol can be safe and effective in certain situations, such as hypertensive emergencies 4, 5.
• One study reported the use of intravenous labetalol in a dose of 20 mg iv bolus, followed by 20 mg every ten minutes until a cumulative dose of 200 mg was attained, to successfully treat a resistant hypertensive emergency 5.
• Another study found that cumulative labetalol doses greater than 300 mg in 24 hours were not associated with adverse safety outcomes, although some patients experienced bradycardia and hypotension 4.
• It is worth noting that the use of high-dose intravenous labetalol requires careful monitoring and may necessitate the availability of rescue agents, such as glucagon, beta-agonists, phosphodiesterase inhibitors, insulin, and vasopressin, in case of severe cardiovascular depression 6.

Administration Considerations

• Intravenous labetalol can be administered as a bolus or continuous infusion, depending on the clinical situation 5, 6.
• The choice of administration method and dose should be guided by the patient's individual needs and response to treatment, as well as careful monitoring of vital signs and potential adverse effects 3, 4.

Safety and Efficacy

• Intravenous labetalol has been shown to be safe and effective in the management of hypertensive emergencies and other conditions, including tachycardia 3, 4, 5.
• However, as with any medication, there is a risk of adverse effects, such as bradycardia, hypotension, and other cardiovascular complications 4, 6.