Reviewed on 10/25/2021

What Is Labetalol and How Does It Work?

Labetalol is a prescription medication used to treat the symptoms of Hypertension (high blood pressure), and Hypertensive Emergency.

  • Labetalol is available under the following different brand names: Trandate

What Are Side Effects Associated with Using Labetalol?

Common side effects of Labetalol include:

  • dizziness, 
  • drowsiness, 
  • tiredness, 
  • nausea, 
  • vomiting, 
  • sudden warmth, 
  • skin redness, 
  • sweating, 
  • numbness, and 
  • tingly feeling in the scalp

Serious side effects of Labetalol include:

  • hives, 
  • difficulty breathing, 
  • swelling of face, lips, tongue, or throat, 
  • severe dizziness, 
  • lightheadedness
  • slow heart rate, 
  • weak pulse
  • fainting
  • slow breathing or breathing that may stop, 
  • shortness of breath (even with mild exertion), 
  • swelling, 
  • rapid weight gain, 
  • severe headache, 
  • blurred vision, 
  • pounding in neck or ears, 
  • loss of appetite, 
  • stomach pain (upper right side), 
  • flu-like symptoms, 
  • itching, 
  • dark urine, and
  • yellowing of the skin or eyes (jaundice)

Rare side effects of Labetalol include:

  • none 
This is not a complete list of side effects and other serious side effects or health problems may occur as a result of the use of this drug. Call your doctor for medical advice about serious side effects or adverse reactions. You may report side effects or health problems to FDA at 1-800-FDA-1088.

What Are Dosages of Labetalol?

Adult and pediatric dosage

Injectable solution

  • 5mg/mL


  • 100mg
  • 200mg
  • 300mg



  • 100 mg orally every 12 hours initially; increased by 100 mg every 12 hours every 2-3 days
  • Usual dose range: 200-400 mg orally every 12 hours; not to exceed 2400 mg/day

Hypertensive Emergency


  • 20 mg IV over 2 minutes initially, then 40-80 mg IV every 10 minutes; total dose not to exceed 300 mg
  • Alternative: 1-2 mg/min by continuous IV infusion; total dose of 300 mg has been used


  • 0.4-1 mg/kg/hr by continuous IV infusion; not to exceed 3 mg/kg/hr

Dosage Considerations – Should be Given as Follows: 

  • See "Dosages."

What Other Drugs Interact with Labetalol?

If your medical doctor is using this medicine to treat your pain, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them.  Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider or pharmacist first

  • Labetalol has severe interactions with the following drug:
  • Labetalol has serious interactions with at least 19 other drugs
  • Labetalol has moderate interactions with at least 168 other drugs.
  • Labetalol has minor interactions with at least 32 other drugs.

This information does not contain all possible interactions or adverse effects.  Visit the RxList Drug Interaction Checker for any drugs interactions. Therefore, before using this product, tell your doctor or pharmacist of all the products you use.  Keep a list of all your medications with you, and share this information with your doctor and pharmacist.  Check with your health care professional or doctor for additional medical advice, or if you have health questions, concerns.

What Are Warnings and Precautions for Labetalol?


Effects of drug abuse

  • None

Short-Term Effects

  • See “What are Side Effects Associated with Using Labetalol?”

Long-Term Effects

  • See “What Are Side Effects Associated with Using Labetalol?”


  • Use with caution in anesthesia or surgery (myocardial depression), bronchospastic disease (not recommended), cerebrovascular insufficiency, diabetes mellitus, hyperthyroidism or thyrotoxicosis, hepatic impairment, renal impairment, peripheral vascular disease, compromised left ventricular function, advanced age, heart failure, pheochromocytoma
  • Increased risk of stroke after surgery
  • Severe hepatic injury reported with use; with prolonged use, monitor liver function tests
  • Sudden discontinuance can exacerbate angina and lead to myocardial infarction
  • Use with caution in patients taking calcium channel blockers, cardiac glycosides, or inhaled anesthetics
  • Intraoperative floppy iris syndrome observed during cataract surgery in some patients treated with alpha1 blockers (labetalol is both an alpha and a beta blocker)
  • Hypotension with or without syncope may occur; monitor
  • Consider pre-existing conditions, such as, sick sinus syndrome before initiating therapy
  • Use caution in patients with history of severe anaphylaxis to allergens; patients taking beta-blockers may become more sensitive to repeated challenges; treatment with epinephrine in patients taking beta-blockers may be ineffective or promote undesirable effects
  • Use with caution in patients with myasthenia gravis, psoriasis, or psychiatric illness (may cause or exacerbate CNS depression)

Pregnancy and Lactation

  • Use with caution if benefits outweigh risks. 
  • Small amounts excreted; use with caution

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