Carbamazepine 100mg Chewable Tabs
WARNING: Blood cell problems have happened, like aplastic anemia and a type of low white blood cell count. Tell your doctor right away if you feel very tired or weak or have a fever, chills, shortness of breath, any unexplained bruising or bleeding, or purple "splotches" on your skin.Call your doctor right away if you have any signs of infection like fever, chills, flu-like signs, very bad sore throat, ear or sinus pain, cough, more sputum or change in color of sputum, pain with passing urine, mouth sores, or a wound that will not heal.A severe skin reaction (Stevens-Johnson syndrome/toxic epidermal necrolysis) may happen. It can cause severe health problems that may not go away, and sometimes death. Get medical help right away if you have signs like red, swollen, blistered, or peeling skin (with or without fever); red or irritated eyes; or sores in your mouth, throat, nose, or eyes.People with a certain gene (HLA-B*1502) have a higher chance of severe and sometimes deadly skin reactions with this drug. This gene is more common in Asian people, including South Asian Indian people. If you have questions, talk with the doctor.People with a certain gene (HLA-A*3101) may have a higher chance of severe allergic reactions with this drug. Allergic reactions can be deadly. If you have questions, talk with the doctor. @ COMMON USES: It is used to treat seizures.It is used to treat pain caused by a problem with a nerve in the face.It may be given to you for other reasons. Talk with the doctor.
Drug Class
Anticonvulsant
Pharmacologic Class
Iminostilbene derivative; Sodium channel blocker
Pregnancy Category
D
FDA Approved
Apr 1974
DEA Schedule
Not Controlled
Overview
What is this medicine?
Carbamazepine is a medication used to treat certain types of seizures (epilepsy) and a specific type of facial nerve pain called trigeminal neuralgia. It works by calming overactive nerve signals in the brain.
How to Use This Medicine
Taking Your Medication
To use this medication correctly, follow your doctor's instructions and read all the information provided. Take your medication with food and chew it thoroughly before swallowing.
Storing and Disposing of Your Medication
Store your medication at room temperature, protected from light, and in a dry place. Avoid storing it in a bathroom. Keep all medications in a safe location, out of the reach of children and pets. When disposing of unused or expired medication, do not flush it down the toilet or pour it down the drain unless instructed to do so. Instead, consult with your pharmacist for guidance on the best disposal method. You may also want to check if there are drug take-back programs available in your area.
Missing 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 use this medication correctly, follow your doctor's instructions and read all the information provided. Take your medication with food and chew it thoroughly before swallowing.
Storing and Disposing of Your Medication
Store your medication at room temperature, protected from light, and in a dry place. Avoid storing it in a bathroom. Keep all medications in a safe location, out of the reach of children and pets. When disposing of unused or expired medication, do not flush it down the toilet or pour it down the drain unless instructed to do so. Instead, consult with your pharmacist for guidance on the best disposal method. You may also want to check if there are drug take-back programs available in your area.
Missing 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 with food to reduce stomach upset and improve absorption.
- Chew tablets thoroughly before swallowing.
- Do not stop taking this medication suddenly, as it can cause seizures to worsen.
- Avoid grapefruit or grapefruit juice, as it can increase carbamazepine levels and side effects.
- Avoid alcohol and other CNS depressants, as they can increase drowsiness and dizziness.
- Use effective non-hormonal birth control, as carbamazepine can make hormonal birth control less effective.
- Wear sunscreen and protective clothing, as carbamazepine can increase sensitivity to the sun.
- Carry identification stating you are taking carbamazepine.
Available Forms & Alternatives
Available Strengths:
- Carbamazepine 100mg/5ml Shake Well
- Carbamazepine 200mg Tablets
- Carbamazepine 200mg Tablets
- Carbamazepine 100mg Chewable Tabs
- Carbamazepine ER 200mg Tablets
- Carbamazepine ER 400mg Tablets
- Carbamazepine 200mg ER Capsules
- Carbamazepine 100mg ER Capsules
- Carbamazepine 100mg ER Capsules
- Carbamazepine 300mg ER Capsules
- Carbamazepine 200mg ER Capsules
- Carbamazepine ER 100mg Tablets
- Carbamazepine ER 100mg Tablets
- Carbamazepine ER 200mg Tablets
- Carbamazepine ER 400mg Tablets
- Carbamazepine 200mg Chw Tablets
Dosing & Administration
Adult Dosing
Standard Dose:
Epilepsy: Initial 200 mg twice daily (chewable tablets). Increase by up to 200 mg/day at weekly intervals. Trigeminal Neuralgia: Initial 100 mg twice daily (chewable tablets). Increase by up to 100 mg every 12 hours as needed.
Dose Range:
400 - 1200 mg
Condition-Specific Dosing:
epilepsyMaintenance:
800-1200 mg/day in divided doses (2-4 times daily)
trigeminalNeuralgiaMaintenance:
200-800 mg/day in divided doses (2-4 times daily)
Pediatric Dosing
Neonatal:
Not established
Infant:
Not established
Child:
Initial: 10-20 mg/kg/day in 2-3 divided doses (chewable tablets). Maintenance: 20-30 mg/kg/day in divided doses. Max: 35 mg/kg/day or 1000 mg/day (for children 12-15 years) or 1200 mg/day (for children >15 years).
Adolescent:
Initial: 200 mg twice daily (chewable tablets). Maintenance: 800-1200 mg/day in divided doses.
Dose Adjustments
Renal Impairment:
Mild:
No specific adjustment recommended, monitor for adverse effects.
Moderate:
No specific adjustment recommended, monitor for adverse effects.
Severe:
Use with caution. Consider lower doses and monitor plasma concentrations. Not dialyzable.
Dialysis:
Not significantly removed by hemodialysis. No supplemental dose needed post-dialysis, but monitor closely.
Hepatic Impairment:
Mild:
Use with caution, monitor liver function tests.
Moderate:
Use with caution, monitor liver function tests and plasma concentrations. Consider lower initial doses.
Severe:
Contraindicated in severe hepatic impairment. Use with extreme caution if unavoidable, monitor liver function and plasma concentrations closely.
Pharmacology
Mechanism of Action
Carbamazepine stabilizes inactivated voltage-gated sodium channels, thereby inhibiting repetitive neuronal firing and reducing synaptic propagation of excitatory impulses. It also has some effects on calcium channels and potassium channels, and may modulate central noradrenergic and serotonergic systems.
Pharmacokinetics
Absorption:
Bioavailability:
75-85% (variable and slow)
Tmax:
4-8 hours (chewable tablets may be faster than conventional tablets)
FoodEffect:
Food increases the rate and extent of absorption.
Distribution:
Vd:
0.8-1.9 L/kg
ProteinBinding:
75-85%
CnssPenetration:
Yes
Elimination:
HalfLife:
Initial: 25-65 hours; Chronic (autoinduction): 12-17 hours
Clearance:
Variable, increases with chronic use due to autoinduction.
ExcretionRoute:
Renal (72%), Fecal (28%)
Unchanged:
< 3% (renal)
Pharmacodynamics
OnsetOfAction:
Variable, typically within hours to days for therapeutic effect.
PeakEffect:
Achieved after several days to weeks of consistent dosing due to autoinduction.
DurationOfAction:
Dependent on half-life, typically requires multiple daily dosing.
Safety & Warnings
BLACK BOX WARNING
WARNING: SERIOUS DERMATOLOGIC REACTIONS AND APLASTIC ANEMIA AND AGRANULOCYTOSIS. Serious dermatologic reactions, including toxic epidermal necrolysis (TEN) and Stevens-Johnson syndrome (SJS), have been reported with carbamazepine treatment. These reactions can be fatal. The risk of these serious dermatologic reactions is increased in patients carrying the HLA-B*1502 allele. Aplastic anemia and agranulocytosis have been reported in association with the use of carbamazepine. These reactions can be fatal. Patients should be advised of the early signs and symptoms of a potential hematologic problem.
Side Effects
Serious Side Effects: Seek Medical Help 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 attention 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
Signs of low sodium levels, including:
+ Headache
+ Trouble focusing
+ Memory problems
+ Feeling confused
+ Weakness
+ Seizures
+ Change in balance
Changes in speech
Hallucinations (seeing or hearing things that are not there)
Changes in eyesight
Trouble walking
A severe and potentially life-threatening condition has been reported in people taking seizure medications like this one. Seek medical help immediately if you experience:
+ Swollen glands
+ Fever
+ Rash
+ Painful sores in the mouth or around the eyes
+ Chest pain
+ Signs of kidney problems, such as:
- Unable to pass urine
- Change in the amount of urine passed
+ Signs of liver problems, including:
- Dark urine
- Tiredness
- Decreased appetite
- Upset stomach or stomach pain
- Light-colored stools
- Vomiting
- Yellow skin or eyes
Neuroleptic malignant syndrome (NMS), a rare but potentially life-threatening condition, may occur. Seek medical help immediately if you experience:
+ Fever
+ Muscle cramps or stiffness
+ Dizziness
+ Severe headache
+ Confusion
+ Change in thinking
+ Fast heartbeat
+ Abnormal heartbeat
+ Excessive sweating
Other 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 contact your doctor or seek medical help if you notice any of the following:
Feeling dizzy, sleepy, tired, or weak
Upset stomach or vomiting
Dry mouth
Constipation
These are not all the possible side effects that may occur. If you have questions or concerns about side effects, contact 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 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
Signs of low sodium levels, including:
+ Headache
+ Trouble focusing
+ Memory problems
+ Feeling confused
+ Weakness
+ Seizures
+ Change in balance
Changes in speech
Hallucinations (seeing or hearing things that are not there)
Changes in eyesight
Trouble walking
A severe and potentially life-threatening condition has been reported in people taking seizure medications like this one. Seek medical help immediately if you experience:
+ Swollen glands
+ Fever
+ Rash
+ Painful sores in the mouth or around the eyes
+ Chest pain
+ Signs of kidney problems, such as:
- Unable to pass urine
- Change in the amount of urine passed
+ Signs of liver problems, including:
- Dark urine
- Tiredness
- Decreased appetite
- Upset stomach or stomach pain
- Light-colored stools
- Vomiting
- Yellow skin or eyes
Neuroleptic malignant syndrome (NMS), a rare but potentially life-threatening condition, may occur. Seek medical help immediately if you experience:
+ Fever
+ Muscle cramps or stiffness
+ Dizziness
+ Severe headache
+ Confusion
+ Change in thinking
+ Fast heartbeat
+ Abnormal heartbeat
+ Excessive sweating
Other 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 contact your doctor or seek medical help if you notice any of the following:
Feeling dizzy, sleepy, tired, or weak
Upset stomach or vomiting
Dry mouth
Constipation
These are not all the possible side effects that may occur. If you have questions or concerns about side effects, contact 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:
- New or worsening skin rash, blistering, peeling skin, or sores in the mouth, nose, throat, or eyes (seek immediate medical attention).
- Fever, chills, sore throat, mouth ulcers, unusual bruising or bleeding, pale skin, or extreme tiredness (signs of blood problems - seek immediate medical attention).
- Yellowing of the skin or eyes (jaundice), dark urine, or light-colored stools (signs of liver problems - seek immediate medical attention).
- Swelling of the face, lips, or tongue, difficulty breathing (signs of severe allergic reaction - seek immediate medical attention).
- New or worsening depression, suicidal thoughts or behavior, anxiety, agitation, panic attacks, insomnia, irritability, hostility, impulsivity, or restlessness (report to doctor immediately).
- Severe dizziness, drowsiness, unsteadiness, or blurred/double vision.
- Unusual weakness or fatigue.
- Confusion or hallucinations.
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 conditions and situations to ensure safe treatment:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Describe the allergic reaction you experienced, including the symptoms that occurred.
Kidney disease, as this may affect how your body processes the medication.
A history of bone marrow problems or porphyria, as these conditions may be exacerbated by the medication.
Any medications you are currently taking, including prescription and over-the-counter (OTC) drugs, natural products, and vitamins. Certain medications, such as those used to treat hepatitis C, HIV, infections, and other conditions, may interact with this medication and should be avoided.
* If you have taken specific medications for depression or Parkinson's disease within the last 14 days, including isocarboxazid, phenelzine, tranylcypromine, selegiline, or rasagiline, as this may increase the risk of very high blood pressure.
To ensure your safety, it is crucial to provide your doctor and pharmacist with a comprehensive list of all your medications, health problems, and allergies. This will help them determine whether it is safe for you to take this medication in conjunction with your other treatments. Never start, stop, or change the dose of any medication without consulting your doctor first.
It is essential to inform your doctor about the following conditions and situations to ensure safe treatment:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Describe the allergic reaction you experienced, including the symptoms that occurred.
Kidney disease, as this may affect how your body processes the medication.
A history of bone marrow problems or porphyria, as these conditions may be exacerbated by the medication.
Any medications you are currently taking, including prescription and over-the-counter (OTC) drugs, natural products, and vitamins. Certain medications, such as those used to treat hepatitis C, HIV, infections, and other conditions, may interact with this medication and should be avoided.
* If you have taken specific medications for depression or Parkinson's disease within the last 14 days, including isocarboxazid, phenelzine, tranylcypromine, selegiline, or rasagiline, as this may increase the risk of very high blood pressure.
To ensure your safety, it is crucial to provide your doctor and pharmacist with a comprehensive list of all your medications, health problems, and allergies. This will help them determine whether it is safe for you to take this medication in conjunction with your other treatments. Never start, stop, or change the dose of any medication without consulting your doctor first.
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
Avoid driving and engaging in activities that require alertness until you understand how this medication affects you.
Monitoring and Follow-up
Have blood work checked as directed by your doctor. Schedule an eye exam as recommended by your doctor.
Interference with Lab Tests
This medication may affect the results of certain lab tests. Inform all your healthcare providers and lab personnel that you are taking this medication.
Pregnancy Tests and Results
This medication may cause false results in some pregnancy tests. Discuss this with your doctor.
Interactions with Other Substances
Before consuming alcohol, marijuana, or other forms of cannabis, or taking prescription or over-the-counter (OTC) medications that may cause drowsiness, consult with your doctor.
Grapefruit Juice and Medication Interaction
If you regularly consume grapefruit juice or eat grapefruit, discuss this with your doctor, as it may interact with your medication.
Stopping the Medication
Do not stop taking this medication abruptly without consulting your doctor, as this may increase the risk of seizures. If you need to stop taking this medication, your doctor will guide you on how to gradually discontinue it.
Seizure Management
If your seizures change or worsen after starting this medication, inform your doctor.
Mental Health and Suicidal Thoughts
Like other seizure medications, this drug may rarely increase the risk of suicidal thoughts or actions, particularly in individuals with a history of suicidal ideation. Monitor your mental health and immediately report any new or worsening symptoms, such as depression, anxiety, restlessness, or mood changes, to your doctor. If you experience suicidal thoughts or actions, seek immediate medical attention.
Cardiovascular Risks
This medication may cause heart problems, including heart failure and abnormal heart rhythms, which can be fatal. Seek immediate medical attention if you experience a rapid, slow, or irregular heartbeat, severe dizziness, fainting, shortness of breath, significant weight gain, or swelling in your arms or legs.
Angioedema
Rarely, this medication can cause a severe reaction called angioedema, which can be life-threatening. Symptoms may include swelling of the hands, face, lips, eyes, tongue, or throat, difficulty breathing, swallowing, or unusual hoarseness. Seek immediate medical help if you experience any of these symptoms.
Special Considerations for Older Adults
If you are 65 or older, use this medication with caution, as you may be more susceptible to side effects.
Reproductive Health
This medication may affect fertility in men. Discuss this with your doctor.
Birth Control and Pregnancy
Birth control pills and other hormone-based contraceptives may be less effective while taking this medication. Use an additional form of birth control, such as a condom, to prevent pregnancy. If you become pregnant or are planning to become pregnant, inform your doctor, as this medication may harm the unborn baby.
Breastfeeding
If you are breastfeeding, consult with your doctor to discuss any potential risks to your baby.
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
Avoid driving and engaging in activities that require alertness until you understand how this medication affects you.
Monitoring and Follow-up
Have blood work checked as directed by your doctor. Schedule an eye exam as recommended by your doctor.
Interference with Lab Tests
This medication may affect the results of certain lab tests. Inform all your healthcare providers and lab personnel that you are taking this medication.
Pregnancy Tests and Results
This medication may cause false results in some pregnancy tests. Discuss this with your doctor.
Interactions with Other Substances
Before consuming alcohol, marijuana, or other forms of cannabis, or taking prescription or over-the-counter (OTC) medications that may cause drowsiness, consult with your doctor.
Grapefruit Juice and Medication Interaction
If you regularly consume grapefruit juice or eat grapefruit, discuss this with your doctor, as it may interact with your medication.
Stopping the Medication
Do not stop taking this medication abruptly without consulting your doctor, as this may increase the risk of seizures. If you need to stop taking this medication, your doctor will guide you on how to gradually discontinue it.
Seizure Management
If your seizures change or worsen after starting this medication, inform your doctor.
Mental Health and Suicidal Thoughts
Like other seizure medications, this drug may rarely increase the risk of suicidal thoughts or actions, particularly in individuals with a history of suicidal ideation. Monitor your mental health and immediately report any new or worsening symptoms, such as depression, anxiety, restlessness, or mood changes, to your doctor. If you experience suicidal thoughts or actions, seek immediate medical attention.
Cardiovascular Risks
This medication may cause heart problems, including heart failure and abnormal heart rhythms, which can be fatal. Seek immediate medical attention if you experience a rapid, slow, or irregular heartbeat, severe dizziness, fainting, shortness of breath, significant weight gain, or swelling in your arms or legs.
Angioedema
Rarely, this medication can cause a severe reaction called angioedema, which can be life-threatening. Symptoms may include swelling of the hands, face, lips, eyes, tongue, or throat, difficulty breathing, swallowing, or unusual hoarseness. Seek immediate medical help if you experience any of these symptoms.
Special Considerations for Older Adults
If you are 65 or older, use this medication with caution, as you may be more susceptible to side effects.
Reproductive Health
This medication may affect fertility in men. Discuss this with your doctor.
Birth Control and Pregnancy
Birth control pills and other hormone-based contraceptives may be less effective while taking this medication. Use an additional form of birth control, such as a condom, to prevent pregnancy. If you become pregnant or are planning to become pregnant, inform your doctor, as this medication may harm the unborn baby.
Breastfeeding
If you are breastfeeding, consult with your doctor to discuss any potential risks to your baby.
Overdose Information
Overdose Symptoms:
- Dizziness, drowsiness, stupor, coma
- Nausea, vomiting
- Slurred speech, nystagmus (uncontrolled eye movements)
- Ataxia (loss of coordination), tremor
- Dilated pupils
- Tachycardia, hypotension, cardiac conduction disturbances
- Respiratory depression
- Seizures (especially in children)
What to Do:
Call 911 or Poison Control (1-800-222-1222) immediately. Supportive care, gastric lavage, activated charcoal, maintain airway, monitor vital signs and cardiac function.
Drug Interactions
Contraindicated Interactions
- MAO inhibitors (concurrent use or within 14 days of discontinuation)
- Nefazodone
- Delavirdine
- Boceprevir
- Telaprevir
Major Interactions
- Strong CYP3A4 inhibitors (e.g., ketoconazole, itraconazole, voriconazole, clarithromycin, erythromycin, ritonavir, grapefruit juice) - can significantly increase carbamazepine levels.
- Strong CYP3A4 inducers (e.g., rifampin, phenytoin, phenobarbital) - can decrease carbamazepine levels.
- Drugs metabolized by CYP3A4, CYP2C9, CYP2C19, CYP2D6 (e.g., oral contraceptives, warfarin, lamotrigine, valproic acid, tricyclic antidepressants, benzodiazepines, calcium channel blockers, some statins) - carbamazepine can decrease their levels.
- Other CNS depressants (e.g., alcohol, opioids, benzodiazepines) - increased sedation.
- Diuretics (e.g., hydrochlorothiazide, furosemide) - increased risk of hyponatremia.
- Lithium - increased risk of neurotoxicity.
- Clozapine - increased risk of agranulocytosis.
Moderate Interactions
- Acetaminophen (increased risk of hepatotoxicity with chronic carbamazepine use)
- Bupropion (lowers seizure threshold)
- Theophylline (carbamazepine decreases levels)
- Cyclosporine, tacrolimus (carbamazepine decreases levels)
- Thyroid hormones (carbamazepine decreases levels)
- Neuromuscular blockers (carbamazepine may antagonize effect)
Minor Interactions
- Folic acid (carbamazepine may decrease levels)
- Vitamin D (carbamazepine may decrease levels)
Monitoring
Baseline Monitoring
Complete Blood Count (CBC) with differential and platelet count
Rationale: To establish baseline and monitor for severe hematologic adverse reactions (aplastic anemia, agranulocytosis).
Timing: Prior to initiation
Liver Function Tests (LFTs)
Rationale: To establish baseline and monitor for hepatotoxicity.
Timing: Prior to initiation
Serum Electrolytes (especially sodium)
Rationale: To establish baseline and monitor for hyponatremia.
Timing: Prior to initiation
Renal Function Tests (BUN, creatinine)
Rationale: To establish baseline and assess renal clearance.
Timing: Prior to initiation
HLA-B*1502 allele testing
Rationale: To screen for increased risk of Stevens-Johnson Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN) in patients of Asian ancestry.
Timing: Prior to initiation (recommended for Asian ancestry)
HLA-A*3101 allele testing
Rationale: To screen for increased risk of SJS/TEN, DRESS, or maculopapular rash in various populations, including European and Japanese ancestry.
Timing: Prior to initiation (consider for all ancestries)
Routine Monitoring
Carbamazepine Plasma Concentrations
Frequency: Initially after 1-2 weeks, then every 1-3 months during titration, then every 3-6 months or as clinically indicated.
Target: 4-12 mcg/mL (therapeutic range)
Action Threshold: Levels >12 mcg/mL may be associated with increased toxicity; levels <4 mcg/mL may indicate subtherapeutic dosing.
Complete Blood Count (CBC) with differential and platelet count
Frequency: Weekly for the first month, then monthly for 2-3 months, then quarterly or as clinically indicated.
Target: WBC >3000/mm³, ANC >1500/mm³, Platelets >100,000/mm³
Action Threshold: Discontinue if WBC <2000/mm³ or ANC <1000/mm³ or Platelets <50,000/mm³.
Liver Function Tests (LFTs)
Frequency: Monthly for the first few months, then quarterly or as clinically indicated.
Target: Within normal limits
Action Threshold: Discontinue if significant abnormalities or signs of liver damage occur.
Serum Sodium
Frequency: Monthly for the first few months, then quarterly or as clinically indicated, especially in elderly or those on diuretics.
Target: 135-145 mEq/L
Action Threshold: Monitor closely if <135 mEq/L; consider dose reduction or discontinuation if symptomatic hyponatremia occurs.
Symptom Monitoring
- Skin rash (any severity, especially blistering or peeling)
- Fever, sore throat, mouth ulcers (signs of hematologic abnormalities)
- Unusual bruising or bleeding
- Yellowing of skin or eyes (jaundice)
- Dark urine, light-colored stools (signs of liver dysfunction)
- Severe fatigue or weakness
- Swelling of face, lips, or tongue
- Difficulty breathing
- Changes in mood or behavior (e.g., suicidal ideation, aggression, agitation)
- Dizziness, drowsiness, ataxia, blurred vision (signs of toxicity)
Special Patient Groups
Pregnancy
Carbamazepine is associated with an increased risk of major congenital malformations, particularly neural tube defects (e.g., spina bifida), craniofacial defects (e.g., cleft lip/palate), and cardiovascular malformations. It should only be used during pregnancy if the potential benefit outweighs the risk to the fetus. Folic acid supplementation is recommended for women of childbearing potential.
Trimester-Specific Risks:
First Trimester:
Highest risk for neural tube defects and other major congenital malformations.
Second Trimester:
Continued risk, but lower for major structural malformations compared to first trimester.
Third Trimester:
Risk of withdrawal symptoms (e.g., seizures, irritability, feeding difficulties) in the neonate if exposed late in pregnancy. Risk of bleeding disorders in the neonate due to vitamin K deficiency (prophylactic vitamin K administration to mother before delivery and to neonate at birth is recommended).
Lactation
Carbamazepine and its active metabolite are excreted into breast milk. While generally considered compatible with breastfeeding with careful monitoring, infants should be monitored for drowsiness, poor feeding, weight gain, and signs of liver dysfunction. The benefits of breastfeeding should be weighed against the potential risks.
Infant Risk:
Low to moderate risk. Monitor for sedation, poor suckling, weight loss, and signs of hepatotoxicity.
Pediatric Use
Dosing is weight-based and requires careful titration. Children may metabolize carbamazepine faster than adults, requiring higher mg/kg doses. Close monitoring for adverse effects, especially hematologic and dermatologic reactions, is crucial. Chewable tablets are suitable for children who can chew and swallow.
Geriatric Use
Elderly patients may be more susceptible to adverse effects, particularly hyponatremia, dizziness, ataxia, and confusion. Lower initial doses and slower titration are recommended. Close monitoring of serum sodium, renal function, and CNS effects is important.
Clinical Information
Clinical Pearls
- Carbamazepine is a potent enzyme inducer, significantly affecting the metabolism of many co-administered drugs, including oral contraceptives, warfarin, and other AEDs. Always check for drug interactions.
- Autoinduction of metabolism occurs, meaning the drug induces its own breakdown, leading to a shorter half-life over time. This necessitates dose adjustments after several weeks of stable dosing.
- Genetic testing for HLA-B*1502 (Asian ancestry) and HLA-A*3101 (various ancestries) is strongly recommended before initiation to reduce the risk of severe skin reactions (SJS/TEN).
- Hyponatremia is a common side effect, especially in the elderly or those on diuretics. Monitor serum sodium levels regularly.
- Chewable tablets should be chewed thoroughly and not swallowed whole to ensure proper absorption and avoid choking hazards, especially in children.
- Therapeutic drug monitoring (TDM) is important to optimize dosing and minimize toxicity, with a target range of 4-12 mcg/mL.
Alternative Therapies
- Phenytoin (for epilepsy, trigeminal neuralgia)
- Valproic Acid (for epilepsy)
- Lamotrigine (for epilepsy)
- Levetiracetam (for epilepsy)
- Oxcarbazepine (structurally related, for epilepsy, trigeminal neuralgia)
- Gabapentin (for neuropathic pain, including trigeminal neuralgia)
- Pregabalin (for neuropathic pain)
- Topiramate (for epilepsy)
- Zonisamide (for epilepsy)
Cost & Coverage
Average Cost:
$10 - $50 per 30 tablets
Generic Available:
Yes
Insurance Coverage:
Tier 1 or Tier 2 (Generic)
General Drug Facts
If your symptoms or health issues persist or worsen, it is essential to contact your doctor promptly. To ensure safe and effective treatment, never share your medication with others or take someone else's medication.
This medication is accompanied by a Medication Guide, a patient fact sheet that provides crucial information. It is vital to read this guide carefully and review it again whenever your prescription is refilled. If you have any questions or concerns about this medication, consult your doctor, pharmacist, or other healthcare provider.
In the event of a suspected overdose, immediately call your local poison control center or seek emergency medical attention. When reporting the incident, be prepared to provide details about the medication taken, the quantity, and the time it occurred.
This medication is accompanied by a Medication Guide, a patient fact sheet that provides crucial information. It is vital to read this guide carefully and review it again whenever your prescription is refilled. If you have any questions or concerns about this medication, consult your doctor, pharmacist, or other healthcare provider.
In the event of a suspected overdose, immediately call your local poison control center or seek emergency medical attention. When reporting the incident, be prepared to provide details about the medication taken, the quantity, and the time it occurred.