Labetalol 300mg Tablets
It is used to treat high blood pressure.
Drug Class
Antihypertensive
Pharmacologic Class
Alpha- and Beta-Adrenergic Blocker
Pregnancy Category
Category C
FDA Approved
Aug 1984
DEA Schedule
Not Controlled
Overview
What is this medicine?
Labetalol is a medication used to treat high blood pressure. It works by relaxing blood vessels and slowing down the heart rate, which helps blood flow more easily and lowers blood pressure. It's a 'dual-action' medicine because it affects two different types of receptors in your body.
How to Use This Medicine
Taking Your Medication Correctly
To get the most benefit from your medication, take it exactly as directed by your doctor. Carefully read all the information provided with your prescription, and follow the instructions closely. Continue taking your medication as prescribed by your doctor or healthcare provider, even if you start to feel better.
Storing and Disposing of Your Medication
Store your medication at room temperature in a dry location, avoiding the bathroom. Keep all medications in a safe and secure place, out of reach of children and pets. Dispose of unused or expired medications properly. Do not flush them down the toilet or pour them down the drain unless instructed to do so by your doctor or pharmacist. If you have questions about disposing of your medication, consult with your pharmacist. You may also want to check if there are any drug take-back programs available in your area.
What to Do If You Miss a Dose
If you miss a dose, take it as soon as you remember. However, if it's close to the time for your next scheduled dose, skip the missed dose and resume your regular dosing schedule. Do not take two doses at the same time or take extra doses to make up for the missed one.
To get the most benefit from your medication, take it exactly as directed by your doctor. Carefully read all the information provided with your prescription, and follow the instructions closely. Continue taking your medication as prescribed by your doctor or healthcare provider, even if you start to feel better.
Storing and Disposing of Your Medication
Store your medication at room temperature in a dry location, avoiding the bathroom. Keep all medications in a safe and secure place, out of reach of children and pets. Dispose of unused or expired medications properly. Do not flush them down the toilet or pour them down the drain unless instructed to do so by your doctor or pharmacist. If you have questions about disposing of your medication, consult with your pharmacist. You may also want to check if there are any drug take-back programs available in your area.
What to Do If You Miss a Dose
If you miss a dose, take it as soon as you remember. However, if it's close to the time for your next scheduled dose, skip the missed dose and resume your regular dosing schedule. Do not take two doses at the same time or take extra doses to make up for the missed one.
Lifestyle & Tips
- Take labetalol exactly as prescribed, usually with food to improve absorption and reduce stomach upset.
- Do not stop taking labetalol suddenly, as this can lead to a sudden increase in blood pressure or chest pain. Your doctor will tell you how to gradually reduce the dose if needed.
- Avoid sudden changes in position (e.g., standing up quickly from a sitting or lying position) to minimize dizziness or lightheadedness caused by orthostatic hypotension.
- Limit alcohol consumption, as it can increase the blood pressure-lowering effects and dizziness.
- Continue to follow a healthy diet (low in sodium, rich in fruits and vegetables), engage in regular physical activity, and manage stress as part of your overall blood pressure management plan.
- Inform your doctor or dentist that you are taking labetalol before any surgery or dental procedures.
Available Forms & Alternatives
Dosing & Administration
Adult Dosing
Standard Dose:
Initial: 100 mg orally twice daily. Maintenance: 200-400 mg orally twice daily. Max: 1200-2400 mg/day in divided doses.
Dose Range:
100 - 2400 mg
Condition-Specific Dosing:
hypertension:
Initial: 100 mg BID; Titrate every 2-3 days by 100 mg BID increments. Usual maintenance: 200-400 mg BID. Max: 2400 mg/day.
Pediatric Dosing
Neonatal:
Not established (limited data, used off-label for severe hypertension, e.g., 0.25-1 mg/kg/dose every 6-12 hours)
Infant:
Not established (limited data, used off-label for severe hypertension, e.g., 0.25-1 mg/kg/dose every 6-12 hours)
Child:
Not established (limited data, used off-label for severe hypertension, e.g., 0.25-1 mg/kg/dose every 6-12 hours)
Adolescent:
Not established (limited data, may use adult dosing for severe hypertension, e.g., 0.25-1 mg/kg/dose every 6-12 hours, max 2400 mg/day)
Dose Adjustments
Renal Impairment:
Mild:
No specific adjustment needed.
Moderate:
No specific adjustment needed.
Severe:
No specific adjustment needed, but monitor for increased effects due to potential accumulation of metabolites.
Dialysis:
Labetalol is not significantly removed by hemodialysis. No supplemental dose needed post-dialysis.
Hepatic Impairment:
Mild:
Caution advised, monitor closely.
Moderate:
Reduce initial dose and titrate slowly due to extensive hepatic metabolism and potential for increased bioavailability.
Severe:
Significant reduction in initial dose and careful titration required due to impaired metabolism and increased bioavailability.
Pharmacology
Mechanism of Action
Labetalol is a non-selective beta-adrenergic receptor blocker and a selective alpha-1 adrenergic receptor blocker. It lowers blood pressure by reducing peripheral vascular resistance (via alpha-1 blockade) and by decreasing cardiac output (via beta-blockade). The ratio of beta- to alpha-blockade is approximately 7:1 orally.
Pharmacokinetics
Absorption:
Bioavailability:
25-30% (due to extensive first-pass metabolism)
Tmax:
1-2 hours (oral)
FoodEffect:
Food increases bioavailability by approximately 20% and reduces peak plasma concentrations.
Distribution:
Vd:
3-16 L/kg
ProteinBinding:
Approximately 50%
CnssPenetration:
Limited
Elimination:
HalfLife:
6-8 hours
Clearance:
Approximately 1600 mL/min
ExcretionRoute:
Renal (primarily as metabolites, ~55-60%), Biliary/Fecal (primarily as metabolites, ~35-40%)
Unchanged:
<5% (renal)
Pharmacodynamics
OnsetOfAction:
20 minutes to 2 hours (oral)
PeakEffect:
1-4 hours (oral)
DurationOfAction:
8-12 hours (oral)
Safety & Warnings
Side Effects
Urgent Side Effects: Seek Medical Attention Immediately
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you notice any of the following symptoms, contact your doctor or seek medical help right away:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Severe dizziness or fainting
Slow heartbeat
Abnormal burning, numbness, or tingling sensations
Erectile dysfunction
Heart failure or worsening of existing heart failure, characterized by:
+ Shortness of breath
+ Sudden weight gain
+ Irregular heartbeat
+ New or worsening swelling in the arms or legs
Liver problems, which may be indicated by:
+ Dark urine
+ Fatigue
+ Decreased appetite
+ Nausea or stomach pain
+ Light-colored stools
+ Vomiting
+ Yellowing of the skin or eyes
If you have a history of heart disease, inform your doctor, as this medication may increase the risk of heart failure.
Other Possible Side Effects
Like all medications, this drug can cause side effects, although many people may not experience any or may only have mild symptoms. If you are bothered by any of the following side effects or if they persist, contact your doctor or seek medical help:
Dizziness
Fatigue
Weakness
Upset stomach
Tingling sensation on the scalp
* Nasal congestion
This is not an exhaustive list of potential side effects. If you have questions or concerns about side effects, consult your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you notice any of the following symptoms, contact your doctor or seek medical help right away:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Severe dizziness or fainting
Slow heartbeat
Abnormal burning, numbness, or tingling sensations
Erectile dysfunction
Heart failure or worsening of existing heart failure, characterized by:
+ Shortness of breath
+ Sudden weight gain
+ Irregular heartbeat
+ New or worsening swelling in the arms or legs
Liver problems, which may be indicated by:
+ Dark urine
+ Fatigue
+ Decreased appetite
+ Nausea or stomach pain
+ Light-colored stools
+ Vomiting
+ Yellowing of the skin or eyes
If you have a history of heart disease, inform your doctor, as this medication may increase the risk of heart failure.
Other Possible Side Effects
Like all medications, this drug can cause side effects, although many people may not experience any or may only have mild symptoms. If you are bothered by any of the following side effects or if they persist, contact your doctor or seek medical help:
Dizziness
Fatigue
Weakness
Upset stomach
Tingling sensation on the scalp
* Nasal congestion
This is not an exhaustive list of potential side effects. If you have questions or concerns about side effects, consult your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Seek Immediate Medical Attention If You Experience:
- Severe dizziness or fainting
- Slow or irregular heartbeat
- Shortness of breath, wheezing, or difficulty breathing (especially if new or worsening)
- Swelling of the ankles or feet
- Unusual tiredness or weakness
- Yellowing of the skin or eyes (jaundice), dark urine, or persistent nausea/vomiting (signs of liver problems)
- Cold hands or feet
Before Using This Medicine
Before Taking This Medication: Important Information to Share with Your Doctor
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Be sure to describe the allergic reaction you experienced, including any symptoms that occurred.
If you have low blood pressure.
If you have any pre-existing medical conditions, including:
+ Respiratory problems, such as asthma or chronic obstructive pulmonary disease (COPD).
+ Heart conditions, including heart block, heart failure (a weakened heart), or shock caused by heart problems.
+ A slow heartbeat.
If you are currently taking diltiazem or verapamil, as these medications may interact with this drug.
Please note that this is not an exhaustive list of all potential interactions. It is crucial to discuss all of your medications, including prescription and over-the-counter (OTC) drugs, natural products, and vitamins, with your doctor and pharmacist. This will help ensure that it is safe to take this medication in conjunction with your other medications and health conditions.
Remember, do not start, stop, or change the dosage of any medication without first consulting your doctor.
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Be sure to describe the allergic reaction you experienced, including any symptoms that occurred.
If you have low blood pressure.
If you have any pre-existing medical conditions, including:
+ Respiratory problems, such as asthma or chronic obstructive pulmonary disease (COPD).
+ Heart conditions, including heart block, heart failure (a weakened heart), or shock caused by heart problems.
+ A slow heartbeat.
If you are currently taking diltiazem or verapamil, as these medications may interact with this drug.
Please note that this is not an exhaustive list of all potential interactions. It is crucial to discuss all of your medications, including prescription and over-the-counter (OTC) drugs, natural products, and vitamins, with your doctor and pharmacist. This will help ensure that it is safe to take this medication in conjunction with your other medications and health conditions.
Remember, do not start, stop, or change the dosage of any medication without first consulting your doctor.
Precautions & Cautions
Important Warnings and Cautions
It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication.
Caution with Daily Activities
Until you know how this medication affects you, avoid driving and other activities that require alertness. To minimize the risk of dizziness or fainting, rise slowly from a sitting or lying position, and be cautious when climbing stairs.
Monitoring Your Condition
Follow your doctor's instructions for checking your blood pressure and heart rate. Additionally, have your blood work and other laboratory tests done as directed by your doctor.
Interference with Lab Tests
This medication may affect certain laboratory tests. Be sure to inform all your healthcare providers and laboratory personnel that you are taking this medication.
Risk of Low Blood Sugar
This medication may mask symptoms of low blood sugar, such as rapid heartbeat, which can increase the risk of severe or prolonged low blood sugar. This risk is higher in people with diabetes, children, and those who are fasting, undergoing surgery, or experiencing nausea and vomiting. If you have questions or concerns, discuss them with your doctor. If you have diabetes, closely monitor your blood sugar levels.
Discontinuing the Medication
Do not stop taking this medication abruptly, as this can lead to worsening chest pain or even a heart attack, especially if you have certain types of heart disease. To avoid side effects, your doctor will instruct you on how to gradually discontinue the medication. If you experience new or worsening chest pain or other heart problems, contact your doctor immediately.
Allergic Reactions
If you have a history of severe allergic reactions, consult your doctor. You may be at risk of a more severe reaction if you are exposed to the allergen again. If you use epinephrine to treat severe allergic reactions, discuss this with your doctor, as epinephrine may be less effective while taking this medication.
Eye Surgery and Other Procedures
If you are scheduled to undergo cataract surgery or other eye procedures, inform your doctor.
Interactions with Over-the-Counter Products
Before using over-the-counter products that may increase blood pressure, such as cough and cold medications, diet pills, stimulants, non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen or naproxen, and certain natural products or aids, consult your doctor.
Special Considerations for Older Adults
If you are 60 years or older, use this medication with caution, as you may be more susceptible to side effects.
Pregnancy and Breastfeeding
If you are pregnant, plan to become pregnant, or are breastfeeding, discuss the benefits and risks of this medication with your doctor.
It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication.
Caution with Daily Activities
Until you know how this medication affects you, avoid driving and other activities that require alertness. To minimize the risk of dizziness or fainting, rise slowly from a sitting or lying position, and be cautious when climbing stairs.
Monitoring Your Condition
Follow your doctor's instructions for checking your blood pressure and heart rate. Additionally, have your blood work and other laboratory tests done as directed by your doctor.
Interference with Lab Tests
This medication may affect certain laboratory tests. Be sure to inform all your healthcare providers and laboratory personnel that you are taking this medication.
Risk of Low Blood Sugar
This medication may mask symptoms of low blood sugar, such as rapid heartbeat, which can increase the risk of severe or prolonged low blood sugar. This risk is higher in people with diabetes, children, and those who are fasting, undergoing surgery, or experiencing nausea and vomiting. If you have questions or concerns, discuss them with your doctor. If you have diabetes, closely monitor your blood sugar levels.
Discontinuing the Medication
Do not stop taking this medication abruptly, as this can lead to worsening chest pain or even a heart attack, especially if you have certain types of heart disease. To avoid side effects, your doctor will instruct you on how to gradually discontinue the medication. If you experience new or worsening chest pain or other heart problems, contact your doctor immediately.
Allergic Reactions
If you have a history of severe allergic reactions, consult your doctor. You may be at risk of a more severe reaction if you are exposed to the allergen again. If you use epinephrine to treat severe allergic reactions, discuss this with your doctor, as epinephrine may be less effective while taking this medication.
Eye Surgery and Other Procedures
If you are scheduled to undergo cataract surgery or other eye procedures, inform your doctor.
Interactions with Over-the-Counter Products
Before using over-the-counter products that may increase blood pressure, such as cough and cold medications, diet pills, stimulants, non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen or naproxen, and certain natural products or aids, consult your doctor.
Special Considerations for Older Adults
If you are 60 years or older, use this medication with caution, as you may be more susceptible to side effects.
Pregnancy and Breastfeeding
If you are pregnant, plan to become pregnant, or are breastfeeding, discuss the benefits and risks of this medication with your doctor.
Overdose Information
Overdose Symptoms:
- Severe hypotension (very low blood pressure)
- Severe bradycardia (very slow heart rate)
- Cardiogenic shock
- Bronchospasm (difficulty breathing)
- Acute cardiac failure
- Convulsions
What to Do:
Seek immediate medical attention. Call 911 or your local emergency number. For poison control, call 1-800-222-1222.
Drug Interactions
Contraindicated Interactions
- Severe bradycardia
- Heart block (second or third degree)
- Cardiogenic shock
- Overt cardiac failure
- Bronchial asthma or history of obstructive airway disease
- Hypersensitivity to labetalol or any component
Major Interactions
- Calcium channel blockers (e.g., verapamil, diltiazem): Risk of severe bradycardia, heart block, and hypotension.
- Anesthetics (e.g., halothane): Potentiation of hypotensive effects.
- Cimetidine: Increases labetalol bioavailability and plasma levels.
- Tricyclic antidepressants: May increase risk of tremor.
Moderate Interactions
- NSAIDs (e.g., ibuprofen, naproxen): May reduce the antihypertensive effect of labetalol.
- Alpha-adrenergic agonists (e.g., phenylephrine, pseudoephedrine): May cause paradoxical hypertension.
- Antidiabetic agents (insulin, oral hypoglycemics): Beta-blockers may mask symptoms of hypoglycemia (e.g., tachycardia).
- Digoxin: May increase digoxin levels and enhance bradycardia.
Minor Interactions
- Not available
Monitoring
Baseline Monitoring
Blood Pressure (BP)
Rationale: To establish baseline and guide initial dosing.
Timing: Prior to initiation of therapy.
Heart Rate (HR)
Rationale: To establish baseline and assess for bradycardia.
Timing: Prior to initiation of therapy.
Liver Function Tests (LFTs)
Rationale: Labetalol is extensively metabolized by the liver; to assess baseline hepatic function.
Timing: Prior to initiation of therapy.
Renal Function (BUN, Creatinine)
Rationale: To assess baseline renal function, though dose adjustment is generally not needed for renal impairment.
Timing: Prior to initiation of therapy.
Routine Monitoring
Blood Pressure (BP)
Frequency: Regularly, especially during dose titration and periodically thereafter.
Target: <140/90 mmHg (or individualized target)
Action Threshold: If BP remains elevated or drops excessively (e.g., symptomatic hypotension).
Heart Rate (HR)
Frequency: Regularly, especially during dose titration and periodically thereafter.
Target: 50-90 bpm (or individualized target)
Action Threshold: If HR <50 bpm or symptomatic bradycardia occurs.
Liver Function Tests (LFTs)
Frequency: Periodically, especially if symptoms of hepatic dysfunction develop.
Target: Within normal limits
Action Threshold: Significant elevation of liver enzymes (e.g., >3x ULN) or signs of liver injury.
Symptom Monitoring
- Dizziness or lightheadedness (especially upon standing, indicating orthostatic hypotension)
- Fatigue or weakness
- Nausea
- Headache
- Shortness of breath or wheezing (indicating bronchospasm)
- Swelling of ankles/feet or increased weight (indicating worsening heart failure)
- Unusual bruising or bleeding (rare, but indicates potential liver dysfunction)
Special Patient Groups
Pregnancy
Labetalol is often considered a first-line agent for the treatment of chronic hypertension and pre-eclampsia in pregnancy. While classified as Category C (older system), clinical experience suggests it is relatively safe and effective for managing hypertension during pregnancy.
Trimester-Specific Risks:
First Trimester:
Limited data, but generally not associated with major congenital malformations. Use only if clearly needed.
Second Trimester:
Commonly used for gestational hypertension and pre-eclampsia. Generally considered safe and effective.
Third Trimester:
Commonly used. Potential for neonatal bradycardia, hypoglycemia, and respiratory depression, especially if used close to delivery. Monitor neonate.
Lactation
Labetalol is excreted into breast milk in small amounts. It is generally considered compatible with breastfeeding (L3 - Moderately Safe) by most experts.
Infant Risk:
Low risk. Monitor breastfed infants for signs of beta-blockade such as bradycardia, hypotension, and lethargy. The amount transferred is typically too low to cause significant effects.
Pediatric Use
Safety and efficacy have not been established in pediatric patients for routine hypertension. Use is generally off-label for severe or emergent hypertension, with dosing based on body weight and careful titration. Close monitoring is essential.
Geriatric Use
Use with caution in elderly patients, starting with lower doses and titrating slowly. Elderly patients may be more sensitive to the hypotensive effects and may have age-related decreases in hepatic function, potentially leading to higher plasma concentrations. Monitor for orthostatic hypotension.
Clinical Information
Clinical Pearls
- Labetalol offers the advantage of both alpha-1 and beta-adrenergic blockade, making it effective in reducing both peripheral vascular resistance and heart rate.
- It is a preferred agent for managing hypertension in pregnancy due to its established safety profile in this population.
- Always advise patients not to discontinue labetalol abruptly to avoid rebound hypertension or angina.
- Orthostatic hypotension is a common side effect, especially at the initiation of therapy or with dose increases. Advise patients to rise slowly.
- Take with food to enhance absorption and reduce variability in plasma concentrations.
Alternative Therapies
- Other beta-blockers (e.g., metoprolol, atenolol, carvedilol)
- ACE inhibitors (e.g., lisinopril, enalapril)
- Angiotensin Receptor Blockers (ARBs) (e.g., losartan, valsartan)
- Calcium Channel Blockers (e.g., amlodipine, nifedipine, felodipine)
- Thiazide diuretics (e.g., hydrochlorothiazide)
- Other alpha-blockers (e.g., prazosin, doxazosin - less common for essential hypertension)
Cost & Coverage
Average Cost:
Varies, typically $10-$50 per 30 tablets (300mg)
Generic Available:
Yes
Insurance Coverage:
Tier 1 or Tier 2 (Generic)
General Drug Facts
If your symptoms or health issues persist or worsen, it's essential to contact your doctor for further guidance. To ensure your safety, never share your medication with others or take someone else's medication. Some medications may come with an additional patient information leaflet, so be sure to check with your pharmacist for more information. If you have any questions or concerns about this medication, don't hesitate to reach out to your doctor, nurse, pharmacist, or other healthcare provider. In the event of a suspected overdose, immediately call your local poison control center or seek medical attention. When seeking help, be prepared to provide details about the medication, including the amount taken and the time it happened, to ensure you receive the best possible care.