Labetalol


Article Author:
Michael Miller


Article Editor:
Christopher Maani


Editors In Chief:
Kranthi Sitammagari
Mayank Singhal


Managing Editors:
Avais Raja
Orawan Chaigasame
Carrie Smith
Abdul Waheed
Khalid Alsayouri
Trevor Nezwek
Radia Jamil
Erin Hughes
Patrick Le
Anoosh Zafar Gondal
Saad Nazir
William Gossman
Hassam Zulfiqar
Hussain Sajjad
Steve Bhimji
Muhammad Hashmi
John Shell
Matthew Varacallo
Heba Mahdy
Ahmad Malik
Sarosh Vaqar
Mark Pellegrini
James Hughes
Beata Beatty
Beenish Sohail
Nazia Sadiq
Hajira Basit
Phillip Hynes


Updated:
6/17/2019 4:26:06 PM

Indications

Due to their negative inotropic and chronotropic actions, beta-adrenergic receptor antagonists (e.g., carvedilol and metoprolol) are typically indicated in individuals with chronic cardiovascular disease (hypertension, coronary artery disease, congestive heart failure) with a significant reduction in mortality.[1]

The FDA-approved indication for labetalol is the treatment of arterial hypertension which ranges from acute hypertensive crises (urgent/emergency) to stable chronic hypertension. Labetalol in clinical practice has several common off-label uses that include acute hypertension in pregnancy and hypertension associated with acute ischemic stroke, and intracranial hemorrhage including subarachnoid hemorrhage. Today, labetalol is usually reserved for the acute management of hypertensive crises.

Labetalol is often chosen as treatment of acute hypertension by anesthesia providers peri-operatively as it produces a dose-related decrease in blood pressure without reflex tachycardia and without significant reduction in heart rate. These effects are produced through a mixture of its alpha- and beta-blocking effects. The hemodynamic effects of labetalol are variable, with small, insignificant changes in cardiac output seen in some studies, and small decreases in total peripheral vascular resistance. This hemodynamic profile is favorable in the perioperative setting when the anesthesia provider desires rapid reduction of blood pressure without the reflex tachycardia, which can potentially further compromise the hemodynamics of a patient under general anesthesia. Similarly, labetalol is a common anti-hypertensive given in the post-anesthesia care unit, again due to its HR sparing effects and allowing better control of blood pressure.[2]

Labetalol is one of the most commonly used anti-hypertensives medications used for the treatment of hypertension during pregnancy. Hypertension during pregnancy is an increasingly common and a leading cause of maternal mortality and morbidity worldwide.  Severe hypertension requires prompt treatment with rapid-acting antihypertensive agents such as labetalol if stroke and placental abruption are to be avoided. Previously, intravenous hydralazine was utilized as a first-line drug for this purpose, although there is a growing experience with other agents, including intravenous labetalol and oral nifedipine. There appears to be a growing concern about the neonatal effects of hydralazine. Treatment aims to lower blood pressure during pregnancy into the mild range (less than 160/100 mm Hg), reduce the risk of stroke and other maternal cardiovascular complications.[3][4]

Due to the alpha1-receptor antagonistic activity of labetalol, blood pressure is lowered more in the standing than in the supine position, but this can lead to symptoms of postural hypotension. When deciding to administer intravenous labetalol, the contribution of the postural component needs to be considered when positioning the patient for treatment. Also, the patient should not be allowed to move to an erect position unmonitored until his or her ability to do so safely is established.

Mechanism of Action

Labetalol is useful as it contains both selective, competitive, alpha1-adrenergic antagonism as well as non-selective, competitive, beta-adrenergic (B1 and B2) blocking activity in a single agent. When analyzed in the laboratory, the activity ratio of alpha to beta-blockade has been estimated to be approximately 1:3 and 1:7 following oral and intravenous (IV) administration, respectively.[5]

Administration

For acute hypertensive events (emergent/urgent) the IV formulation is indicated and an initial dose of a 10- to 20-mg IV push, with repeat boluses administered every 10 minutes until the systolic blood pressure is within the desired range or a maximum dose of 300 mg per 24-hour period is reached. A dose of 20 mg correlates with approximately 0.25 mg/kg in an 80-kg patient. A continuous infusion can also be considered and initially started at 0.5 to 2 mg per minute with the potential to titrate up to 10 mg per minute.[1]

Labetalol is metabolized by the liver resulting in an inactive glucuronide conjugate. It has an onset of action within 2 to 5 minutes, reaches its peak effects at 5 to 15 minutes, has an elimination half-life of 5.5 hours, and a duration of action up to four hours.

For a hypertensive emergency in pregnancy (systolic BP equal to 160 mm Hg or diastolic BP equal to 110 mm Hg), which is officially an off-label use, the initial dosing scheme is reportedly very similar to treating non-pregnant patients with acute hypertension with 20 mg as an initial dose. If blood pressure still exceeds this threshold, it is reasonable to consider increasing the dose every 10 minutes in increments of 20 to 40 mg to a maximum single dose of 80 mg. A maximum total cumulative dose of 300 mg is still recommended in this scenario.

Adverse Effects

Overall labetalol is usually well tolerated. Most adverse effects are typically mild and transient. As previously described above, symptomatic postural hypotension is a potential occurrence if patients are tilted or allowed to change positions from the supine or seated position to standing too quickly. This is especially important in the post-operative period (PACU or the ward) when managing a hypertensive patient with labetalol who is otherwise able to ambulate to the bathroom. Increased sweating, as well as flushing, have been reported with the use of labetalol. It seems the incidence of adverse reactions after administering labetalol seems to be dose-dependent.

As with all beta-blockers, labetalol has negative inotropic effects and has the potential to cause acute left ventricular failure if given in sufficiently large enough doses to those patients who have impaired function of the left ventricle. All beta-blockers can exacerbate intermittent claudication and Raynaud phenomenon in patients with the coexisting peripheral vascular disease. Another important consideration for anesthesia providers in the perioperative period is that non-selective beta blockers that interact with beat receptors can result in bronchospasm in patients with a history of asthma or chronic obstructive pulmonary disease due to antagonism of beta receptors. Sudden withdrawal of beta-blockers can result in increased sensitivity to catecholamines. This upregulation can lead to tachyarrhythmias, acute hypertensive crises, and palpitations although this is more common with chronic use.[6]

Contraindications

Labetalol, as a member of the beta-blocker class, is contraindicated and its use strongly cautioned in patients with bronchial asthma, overt cardiac failure, greater-than-first­ degree heart block, cardiogenic shock, severe bradycardia, as well as other conditions associated with severe and prolonged hypotension. Of course, it should be avoided in patients with a history of hypersensitivity to any component of the drug to avoid any degree of allergic reaction.[7]

Monitoring

There are no specific drug monitoring requirements for labetalol. As it is typically used for severe acute hypertension and not chronic use, no monitoring is necessary. Also, it is a safe drug with a large margin of safety with dosing permitted to an upper limit of 300 mg per day.

Toxicity

Supportive care and close monitoring are the staples of treatment for an overdose of beta-blockers with the addition of glucagon for severe refractory hypotension and bradycardia.

Glucagon provides several important clinical effects when used for beta-blocker overdose. It provides an increase in HR and improves both myocardial contractility as well as atrioventricular conduction. Its MOA seems to be independent of the beta-adrenergic binding site allowing it to be effective. The recommended initial dose of glucagon for the purpose of reversing severe symptomatic beta-blockade is 50 mcg/kg IV as a loading dose, followed by an infusion of 1 to 15 mg per hour IV, titrated to clinical response and improvement.[8]

Enhancing Healthcare Team Outcomes

As labetalol is typically used for the treatment of acute hypertension, whether that be an emergency or urgency, an interprofessional team approach and effective communication are essential for quality patient care. In the emergency department, swift intake and triaging by the nurse or medical technician to identify a patient with the dangerously elevated blood pressure and quickly, but effectively to convey the critical information to a physician or provider is necessary. If hospital admission is warranted, communicating the crucial details of the patient's presentation, medical history, and the treatment and current medical workup that have been completed are important, so time and resources are not wasted on repeating tests and exams.


Interested in Participating?

We are looking for contributors to author, edit, and peer review our vast library of review articles and multiple choice questions. In as little as 2-3 hours you can make a significant contribution to your specialty. In return for a small amount of your time, you will receive free access to all content and you will be published as an author or editor in eBooks, apps, online CME/CE activities, and an online Learning Management System for students, teachers, and program directors that allows access to review materials in over 500 specialties.

Improve Content - Become an Author or Editor

This is an academic project designed to provide inexpensive peer-reviewed Apps, eBooks, and very soon an online CME/CE system to help students identify weaknesses and improve knowledge. We would like you to consider being an author or editor. Please click here to learn more. Thank you for you for your interest, the StatPearls Publishing Editorial Team.

Labetalol - Questions

Take a quiz of the questions on this article.

Take Quiz
Which medication has both alpha and beta blocking activity?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
Which of the following adrenergic antagonist has both alpha and beta blocking activity?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
Which drug has both alpha and beta sympathetic blocking ability and is used to treat hypertension?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
Which of the following is not true of labetalol?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
Which receptor is not antagonized by labetalol?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
The metabolism of labetalol takes place in what location?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
Which pharmacological effect is NOT seen with labetalol?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
In which of the following conditions is labetalol contraindicated for blood pressure control?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
Which of the following drugs is FDA approved to treat hypertensive emergency.



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
Which of the following beta-blockers also block alpha receptors?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
A patient is on a labetalol hydrochloride continuous infusion at 2 mg/minute for severe hypertension. What cumulative dose should not be exceeded?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
You have just admitted a patient with malignant hypertension to the intensive care unit. His blood pressure is 220/110 mmHg. He has been complaining of a headache and blurry vision for the past 8 hours. After having started an intravenous line, you decide to administer him an antihypertensive with the longest half-life. What medication will you select?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
Which of the following is not a hemodynamic consequence of labetalol?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
Which of the following is not a contraindication for labetalol?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
Labetalol blocks which of the following adrenergic receptors?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
Labetalol has all of the following hemodynamic consequences except which one?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
Which of the following is not a contraindication for labetalol use?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
An adult patient is being treated with IV labetalol. What is the maximum recommended total 24-hour dose of IV labetalol?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up

Labetalol - References

References

Peacock WF 4th,Hilleman DE,Levy PD,Rhoney DH,Varon J, A systematic review of nicardipine vs labetalol for the management of hypertensive crises. The American journal of emergency medicine. 2012 Jul     [PubMed]
Bailey B, Glucagon in beta-blocker and calcium channel blocker overdoses: a systematic review. Journal of toxicology. Clinical toxicology. 2003     [PubMed]
Elatrous S,Nouira S,Ouanes Besbes L,Marghli S,Boussarssar M,Sakkouhi M,Abroug F, Short-term treatment of severe hypertension of pregnancy: prospective comparison of nicardipine and labetalol. Intensive care medicine. 2002 Sep     [PubMed]
Duley L,Henderson-Smart DJ,Meher S, Drugs for treatment of very high blood pressure during pregnancy. The Cochrane database of systematic reviews. 2006 Jul 19     [PubMed]
Baum T,Sybertz EJ, Pharmacology of labetalol in experimental animals. The American journal of medicine. 1983 Oct 17     [PubMed]
Muzzi DA,Black S,Losasso TJ,Cucchiara RF, Labetalol and esmolol in the control of hypertension after intracranial surgery. Anesthesia and analgesia. 1990 Jan     [PubMed]
Facchini E,Degiovanni A,Cavallino C,Lupi A,Rognoni A,Bongo AS, Beta-Blockers and Nitrates: Pharmacotherapy and Indications. Cardiovascular     [PubMed]
Morales DR,Jackson C,Lipworth BJ,Donnan PT,Guthrie B, Adverse respiratory effect of acute β-blocker exposure in asthma: a systematic review and meta-analysis of randomized controlled trials. Chest. 2014 Apr     [PubMed]

Disclaimer

The intent of StatPearls is to provide practice questions and explanations to assist you in identifying and resolving knowledge deficits. These questions and explanations are not intended to be a source of the knowledge base of all of medicine, nor is it intended to be a board or certification review of PA-Hospital Medicine. The authors or editors do not warrant the information is complete or accurate. The reader is encouraged to verify each answer and explanation in several references. All drug indications and dosages should be verified before administration.

StatPearls offers the most comprehensive database of free multiple-choice questions with explanations and short review chapters ever developed. This system helps physicians, medical students, dentists, nurses, pharmacists, and allied health professionals identify education deficits and learn new concepts. StatPearls is not a board or certification review system for PA-Hospital Medicine, it is a learning system that you can use to help improve your knowledge base of medicine for life-long learning. StatPearls will help you identify your weaknesses so that when you are ready to study for a board or certification exam in PA-Hospital Medicine, you will already be prepared.

Our content is updated continuously through a multi-step peer review process that will help you be prepared and review for a thorough knowledge of PA-Hospital Medicine. When it is time for the PA-Hospital Medicine board and certification exam, you will already be ready. Besides online study quizzes, we also publish our peer-reviewed content in eBooks and mobile Apps. We also offer inexpensive CME/CE, so our content can be used to attain education credits while you study PA-Hospital Medicine.