Labetalol 100mg Tablets
It is used to treat high blood pressure.
Drug Class
Antihypertensive
Pharmacologic Class
Alpha- and Beta-Adrenergic Blocker
Pregnancy 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 your heart rate, which helps your heart pump blood more easily throughout your body.
How to Use This Medicine
Taking Your Medication Correctly
To get the most benefit from your medication, it's essential to use it as directed by your doctor. Carefully read all the information provided with your medication 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
To maintain the quality and safety of your medication, store it at room temperature in a dry place, avoiding bathrooms. Keep all medications in a secure location, out of the reach of children and pets. When disposing of unused or expired medications, do not flush them down the toilet or pour them down the drain unless specifically instructed to do so. Instead, consult with your pharmacist for guidance on the best disposal method. You may also want to explore local drug take-back programs 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, it's essential to use it as directed by your doctor. Carefully read all the information provided with your medication 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
To maintain the quality and safety of your medication, store it at room temperature in a dry place, avoiding bathrooms. Keep all medications in a secure location, out of the reach of children and pets. When disposing of unused or expired medications, do not flush them down the toilet or pour them down the drain unless specifically instructed to do so. Instead, consult with your pharmacist for guidance on the best disposal method. You may also want to explore local drug take-back programs 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 medication exactly as prescribed, do not stop abruptly without consulting your doctor.
- Avoid sudden changes in position (e.g., standing up quickly from sitting or lying down) to prevent dizziness or lightheadedness.
- Limit alcohol intake, as it can increase the blood pressure-lowering effect.
- Maintain a healthy diet (low in sodium, rich in fruits and vegetables).
- Engage in regular physical activity as advised by your doctor.
- Monitor your blood pressure and heart rate at home as instructed by your healthcare provider.
- 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:
100 mg orally twice daily, may be increased by 100 mg increments every 2-3 days.
Dose Range:
100 - 2400 mg
Condition-Specific Dosing:
hypertension:
Initial: 100 mg twice daily. Maintenance: 200-400 mg twice daily. Max: 2400 mg/day in divided doses.
hypertensive_emergency_oral_stepdown:
Initial: 200 mg, then 200-400 mg every 6-12 hours as needed.
Pediatric Dosing
Neonatal:
Not established
Infant:
Not established
Child:
Not established for routine use; limited data for hypertension: 0.3-1 mg/kg/dose orally, up to 10-12 mg/kg/day divided twice daily.
Adolescent:
Similar to adult dosing, but start low and titrate based on response and tolerability.
Dose Adjustments
Renal Impairment:
Mild:
No adjustment needed.
Moderate:
No adjustment needed.
Severe:
No adjustment needed, but use with caution due to potential for accumulation of metabolites.
Dialysis:
Not significantly removed by hemodialysis. No supplemental dose needed after dialysis.
Hepatic Impairment:
Mild:
Use with caution.
Moderate:
Reduced dosage may be necessary due to decreased metabolism and increased bioavailability. Start with lower doses (e.g., 50 mg twice daily) and titrate carefully.
Severe:
Reduced dosage may be necessary due to decreased metabolism and increased bioavailability. Start with lower doses (e.g., 50 mg twice daily) and titrate carefully.
Pharmacology
Mechanism of Action
Labetalol is a non-selective beta-adrenergic receptor blocker (beta1 and beta2) and a selective alpha1-adrenergic receptor blocker. It lowers blood pressure by reducing peripheral vascular resistance (alpha1 blockade) and by decreasing cardiac output (beta blockade). It also has intrinsic sympathomimetic activity (ISA) at beta2 receptors and membrane-stabilizing activity.
Pharmacokinetics
Absorption:
Bioavailability:
25-30% (highly variable due to extensive first-pass metabolism)
Tmax:
1-2 hours
FoodEffect:
Food increases bioavailability by approximately 20% and prolongs Tmax.
Distribution:
Vd:
3-16 L/kg
ProteinBinding:
50%
CnssPenetration:
Limited
Elimination:
HalfLife:
6-8 hours
Clearance:
Approximately 1600 mL/min
ExcretionRoute:
Mainly renal (approximately 55-60% as metabolites, <5% as unchanged drug); fecal (approximately 30% as metabolites).
Unchanged:
Less than 5%
Pharmacodynamics
OnsetOfAction:
Oral: 20 minutes to 2 hours
PeakEffect:
Oral: 1-4 hours
DurationOfAction:
Oral: 8-12 hours
Safety & Warnings
Side Effects
Urgent Side Effects: Seek Medical Help Right Away
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 attention immediately:
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
+ Yellow skin or eyes
Other Possible Side Effects
Like all medications, this drug can cause side effects. While many people may not experience any side effects or only minor ones, it's essential to discuss any concerns with your doctor. If you experience any of the following side effects or any other unusual symptoms, contact your doctor for guidance:
Dizziness
Fatigue
Weakness
Upset stomach
Tingling sensation on the scalp
* Stuffy nose
Reporting Side Effects
This list is not exhaustive, and you may experience other side effects not mentioned here. 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 attention immediately:
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
+ Yellow skin or eyes
Other Possible Side Effects
Like all medications, this drug can cause side effects. While many people may not experience any side effects or only minor ones, it's essential to discuss any concerns with your doctor. If you experience any of the following side effects or any other unusual symptoms, contact your doctor for guidance:
Dizziness
Fatigue
Weakness
Upset stomach
Tingling sensation on the scalp
* Stuffy nose
Reporting Side Effects
This list is not exhaustive, and you may experience other side effects not mentioned here. 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
- Very slow heart rate (less than 50 beats per minute)
- Difficulty breathing or worsening asthma/COPD symptoms
- Swelling in your ankles or feet
- Unusual weight gain
- Signs of liver problems (e.g., yellowing of skin/eyes, dark urine, persistent nausea/vomiting, severe stomach pain)
- Cold hands or feet
- Depression
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 symptoms you experienced.
If you have low blood pressure.
If you have any of the following health conditions:
+ Respiratory problems, such as asthma or chronic obstructive pulmonary disease (COPD)
+ Heart block or heart failure (a weakened heart)
+ Shock caused by heart problems
+ A slow heartbeat
If you are currently taking diltiazem or verapamil.
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 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 symptoms you experienced.
If you have low blood pressure.
If you have any of the following health conditions:
+ Respiratory problems, such as asthma or chronic obstructive pulmonary disease (COPD)
+ Heart block or heart failure (a weakened heart)
+ Shock caused by heart problems
+ A slow heartbeat
If you are currently taking diltiazem or verapamil.
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 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 understand how this medication affects you, avoid driving and other tasks 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 a rapid heartbeat, which can increase the risk of severe or prolonged low blood sugar. This risk is higher in people with diabetes, children, and individuals who are fasting, undergoing surgery, or experiencing nausea and vomiting. If you have questions or concerns, discuss them with your doctor.
Managing Diabetes
If you have high blood sugar (diabetes), it is crucial to monitor your blood sugar levels closely while taking this medication.
Stopping 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 stop taking this 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, as you may be at risk of an even more severe reaction. 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 Procedures
If you are scheduled to undergo cataract surgery or other eye procedures, inform your doctor.
Interactions with Other Medications
Before using over-the-counter (OTC) products that may increase blood pressure, such as cough or cold medications, diet pills, stimulants, non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen or naproxen, or certain natural products, 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 understand how this medication affects you, avoid driving and other tasks 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 a rapid heartbeat, which can increase the risk of severe or prolonged low blood sugar. This risk is higher in people with diabetes, children, and individuals who are fasting, undergoing surgery, or experiencing nausea and vomiting. If you have questions or concerns, discuss them with your doctor.
Managing Diabetes
If you have high blood sugar (diabetes), it is crucial to monitor your blood sugar levels closely while taking this medication.
Stopping 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 stop taking this 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, as you may be at risk of an even more severe reaction. 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 Procedures
If you are scheduled to undergo cataract surgery or other eye procedures, inform your doctor.
Interactions with Other Medications
Before using over-the-counter (OTC) products that may increase blood pressure, such as cough or cold medications, diet pills, stimulants, non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen or naproxen, or certain natural products, 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 (low blood pressure)
- Bradycardia (slow heart rate)
- Heart block
- Cardiogenic shock
- Bronchospasm
- Acute cardiac failure
- Seizures
What to Do:
Seek immediate medical attention. Call 911 or your local emergency number. For poison control, call 1-800-222-1222. Treatment is supportive and symptomatic, including IV fluids, vasopressors, atropine for bradycardia, glucagon, and bronchodilators for bronchospasm.
Drug Interactions
Contraindicated Interactions
- Bronchial asthma
- Overt cardiac failure
- Greater than first-degree heart block
- Cardiogenic shock
- Severe bradycardia
- Severe chronic obstructive pulmonary disease (COPD)
Major Interactions
- Non-dihydropyridine calcium channel blockers (e.g., verapamil, diltiazem) - risk of severe bradycardia, heart block, or heart failure.
- Class I antiarrhythmics (e.g., disopyramide, quinidine) - risk of additive myocardial depression.
- Clonidine - risk of rebound hypertension upon clonidine withdrawal.
- Fingolimod - risk of severe bradycardia.
- MAO inhibitors - risk of hypertensive crisis.
Moderate Interactions
- NSAIDs (e.g., ibuprofen, naproxen) - may reduce antihypertensive effect.
- Tricyclic antidepressants (TCAs) - may increase risk of tremor.
- Alpha-blockers (e.g., prazosin) - increased risk of first-dose hypotension.
- Insulin and oral hypoglycemics - may mask symptoms of hypoglycemia (tachycardia, palpitations).
- Inhaled anesthetics (e.g., halothane, isoflurane) - enhanced hypotensive effects.
- Cimetidine - increases labetalol bioavailability.
Minor Interactions
- Alcohol - additive hypotensive effects.
- Antacids - may decrease labetalol absorption.
Monitoring
Baseline Monitoring
Blood Pressure (BP)
Rationale: To establish baseline and guide initial dosing.
Timing: Prior to initiation.
Heart Rate (HR)
Rationale: To establish baseline and assess for bradycardia.
Timing: Prior to initiation.
Renal Function (SCr, BUN)
Rationale: To assess baseline kidney function, though no dose adjustment typically needed for renal impairment.
Timing: Prior to initiation.
Liver Function Tests (LFTs)
Rationale: To assess baseline hepatic function, as labetalol is metabolized in the liver and hepatic impairment requires dose adjustment.
Timing: Prior to initiation.
Routine Monitoring
Blood Pressure (BP)
Frequency: Regularly, especially during dose titration and periodically thereafter (e.g., weekly during titration, then monthly/quarterly).
Target: <130/80 mmHg (or individualized target based on guidelines/comorbidities).
Action Threshold: If BP remains elevated above target, consider dose increase or add therapy. If BP is too low (<90/60 mmHg or symptomatic), consider dose reduction.
Heart Rate (HR)
Frequency: Regularly, especially during dose titration and periodically thereafter.
Target: 50-90 bpm (avoiding symptomatic bradycardia).
Action Threshold: If HR <50 bpm or symptomatic bradycardia, consider dose reduction or discontinuation.
Symptoms of Orthostatic Hypotension
Frequency: Regularly, especially during initial therapy and dose increases.
Target: Absence of dizziness, lightheadedness upon standing.
Action Threshold: If symptomatic orthostasis occurs, advise slow position changes; consider dose reduction if persistent.
Symptom Monitoring
- Dizziness
- Lightheadedness
- Fatigue
- Nausea
- Headache
- Shortness of breath (especially in patients with underlying respiratory conditions)
- Bradycardia symptoms (e.g., syncope, extreme fatigue)
- Signs of liver injury (e.g., dark urine, jaundice, persistent nausea/vomiting, abdominal pain)
Special Patient Groups
Pregnancy
Labetalol is Pregnancy Category C. It should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. It is often used for hypertension in pregnancy, particularly pre-eclampsia, but careful monitoring of the fetus is required.
Trimester-Specific Risks:
First Trimester:
Limited data, but generally considered safer than some other antihypertensives. Potential for fetal growth restriction.
Second Trimester:
Commonly used for chronic hypertension or pre-eclampsia. Monitor for fetal growth and well-being.
Third Trimester:
Commonly used. Neonates exposed to beta-blockers in utero may experience bradycardia, hypoglycemia, and respiratory depression. Monitor neonate for 24-48 hours after birth.
Lactation
Labetalol is excreted in breast milk in small amounts. It is generally considered compatible with breastfeeding (Lactation Risk Category L2 - Safer). Monitor breastfed infant for signs of beta-blockade (e.g., bradycardia, lethargy, poor feeding).
Infant Risk:
Low risk; monitor for bradycardia, hypotension, and hypoglycemia.
Pediatric Use
Safety and efficacy have not been established for routine pediatric use. Limited data suggest it may be used for hypertension in children, but dosing must be carefully titrated based on weight and response. Not recommended for neonates.
Geriatric Use
Use with caution in elderly patients, starting with lower doses and titrating slowly, due to increased likelihood of decreased renal or hepatic function and increased sensitivity to hypotensive effects. Monitor closely for orthostatic hypotension and bradycardia.
Clinical Information
Clinical Pearls
- Labetalol offers the advantage of both alpha- and beta-blockade, making it effective for hypertension, especially in situations where both vasodilation and heart rate control are desired (e.g., hypertensive emergencies, pre-eclampsia).
- Unlike some other beta-blockers, labetalol has less propensity to cause bradycardia at equipotent antihypertensive doses due to its alpha-blocking effects.
- Patients should be advised to avoid abrupt discontinuation of labetalol, as this can precipitate angina, myocardial infarction, or rebound hypertension.
- Administer with food to enhance bioavailability and reduce variability in absorption.
- Monitor for orthostatic hypotension, especially during initial dosing and dose increases, as this is a common side effect due to alpha-1 blockade.
Alternative Therapies
- ACE inhibitors (e.g., lisinopril, enalapril)
- Angiotensin Receptor Blockers (ARBs) (e.g., losartan, valsartan)
- Calcium Channel Blockers (CCBs) (e.g., amlodipine, nifedipine, verapamil, diltiazem)
- Thiazide Diuretics (e.g., hydrochlorothiazide)
- Other Beta-blockers (e.g., metoprolol, atenolol, propranolol)
- Other Alpha-blockers (e.g., prazosin, doxazosin)
Cost & Coverage
Average Cost:
$10 - $50 per 30 tablets (100mg generic)
Generic Available:
Yes
Insurance Coverage:
Tier 1 or Tier 2 (preferred generic)
General Drug Facts
If your symptoms or health issues persist or worsen, it is 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 it's a good idea 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 facilitate prompt and effective treatment.