Carbamazepine 200mg Chw Tablets
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, Mood Stabilizer, Trigeminal Neuralgia Agent
Pharmacologic Class
Iminostilbene derivative, Sodium channel blocker
Pregnancy Category
Category D
FDA Approved
Sep 1968
DEA Schedule
Not Controlled
Overview
What is this medicine?
Carbamazepine is a medication used to treat certain types of seizures (epilepsy), nerve pain (like trigeminal neuralgia), and bipolar disorder. It works by calming overactive nerves in the brain.
How to Use This Medicine
Taking Your Medication
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. Take your medication with food to help your body absorb it properly. Be sure to chew the medication thoroughly before swallowing.
Storing and Disposing of Your Medication
To maintain the effectiveness and safety of your medication, store it at room temperature, away from direct light and moisture. Keep it in a dry place, such as a closet or cabinet, and avoid storing it in the bathroom. Always keep your medication in a secure location, out of the reach of children and pets. If you have unused or expired medication, dispose of it properly. Do not flush it down the toilet or pour it down the drain unless instructed to do so by your pharmacist or healthcare provider. If you're unsure about the best way to dispose of your medication, consult with your pharmacist, who may be aware of local drug take-back programs.
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 a 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. Take your medication with food to help your body absorb it properly. Be sure to chew the medication thoroughly before swallowing.
Storing and Disposing of Your Medication
To maintain the effectiveness and safety of your medication, store it at room temperature, away from direct light and moisture. Keep it in a dry place, such as a closet or cabinet, and avoid storing it in the bathroom. Always keep your medication in a secure location, out of the reach of children and pets. If you have unused or expired medication, dispose of it properly. Do not flush it down the toilet or pour it down the drain unless instructed to do so by your pharmacist or healthcare provider. If you're unsure about the best way to dispose of your medication, consult with your pharmacist, who may be aware of local drug take-back programs.
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 a missed one.
Lifestyle & Tips
- Take exactly as prescribed, do not stop abruptly without consulting your doctor.
- Chew chewable tablets thoroughly before swallowing.
- Avoid alcohol, as it can increase side effects like dizziness and drowsiness.
- Be aware that this medication can cause dizziness or drowsiness, especially when starting or changing doses. Avoid driving or operating heavy machinery until you know how it affects you.
- Use effective non-hormonal birth control methods, as carbamazepine can make hormonal birth control less effective.
- Avoid excessive sun exposure and use sunscreen, as carbamazepine can cause photosensitivity.
- Maintain good oral hygiene, as chewable tablets contain sugar and can contribute to dental caries.
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 (BID) for conventional tablets or 100 mg four times daily (QID) for chewable/suspension. Increase by up to 200 mg/day at weekly intervals. Maintenance: 800-1200 mg/day in divided doses. Trigeminal Neuralgia: Initial 100 mg BID. Increase by 100 mg every 12 hours as needed. Maintenance: 200-400 mg BID.
Dose Range:
200 - 1600 mg
Condition-Specific Dosing:
Epilepsy:
Initial 200 mg BID (conventional) or 100 mg QID (chewable/suspension), max 1600 mg/day.
Trigeminal Neuralgia:
Initial 100 mg BID, max 1200 mg/day.
Pediatric Dosing
Neonatal:
Not established
Infant:
Not established
Child:
Epilepsy (6-12 years): Initial 100 mg BID or 50 mg QID (chewable/suspension). Increase by 100 mg/day at weekly intervals. Maintenance: 400-800 mg/day. Epilepsy (>12 years): Same as adult initial dosing, maintenance 800-1200 mg/day.
Adolescent:
Epilepsy (>12 years): Same as adult initial dosing, maintenance 800-1200 mg/day.
Dose Adjustments
Renal Impairment:
Mild:
No specific adjustment, monitor for adverse effects.
Moderate:
No specific adjustment, monitor for adverse effects.
Severe:
Use with caution. Consider lower doses and monitor drug levels and clinical response. Not dialyzable.
Dialysis:
Not significantly removed by hemodialysis. Supplemental dose not typically needed after dialysis, but monitor closely.
Hepatic Impairment:
Mild:
Use with caution, monitor LFTs.
Moderate:
Use with caution, consider lower initial doses and monitor LFTs and drug levels.
Severe:
Contraindicated in severe hepatic impairment due to risk of liver damage and altered metabolism.
Pharmacology
Mechanism of Action
Carbamazepine stabilizes hyperexcited nerve membranes, inhibits repetitive neuronal discharges, and reduces synaptic propagation of excitatory impulses. It is thought to act by blocking voltage-gated sodium channels in the neuronal membrane, thereby limiting the influx of sodium ions and preventing the generation of action potentials.
Pharmacokinetics
Absorption:
Bioavailability:
75-85%
Tmax:
4-8 hours (conventional tablets), 3-12 hours (chewable/suspension)
FoodEffect:
Food can increase the rate and extent of absorption.
Distribution:
Vd:
0.8-1.9 L/kg
ProteinBinding:
75-80%
CnssPenetration:
Yes
Elimination:
HalfLife:
Initial: 25-65 hours; Chronic (due to autoinduction): 12-17 hours
Clearance:
Variable, increases with chronic use due to autoinduction.
ExcretionRoute:
Renal (72%), Fecal (28%)
Unchanged:
2-3% (renal)
Pharmacodynamics
OnsetOfAction:
Variable, typically within hours to days for therapeutic effect.
PeakEffect:
Correlates with Tmax (4-8 hours for conventional, 3-12 hours for chewable/suspension).
DurationOfAction:
Related to half-life, requiring multiple daily doses due to autoinduction.
Confidence:
Medium
Safety & Warnings
BLACK BOX WARNING
WARNINGS: APLASTIC ANEMIA AND AGRANULOCYTOSIS. Serious dermatologic reactions, including toxic epidermal necrolysis (TEN) and Stevens-Johnson syndrome (SJS).
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
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 occurred in people taking seizure medications like this one. Seek medical help right away 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
- Throwing up
- Yellow skin or eyes
Neuroleptic malignant syndrome (NMS), a rare but potentially life-threatening condition, may occur. Seek medical help right away if you experience:
+ Fever
+ Muscle cramps or stiffness
+ Dizziness
+ Severe headache
+ Confusion
+ Change in thinking
+ Fast heartbeat
+ Abnormal heartbeat
+ Excessive sweating
Other Possible Side Effects
Like all medications, this drug may cause side effects. Many people experience no side effects or only mild ones. If you notice any of the following side effects or any other symptoms that bother you or do not go away, contact your doctor or seek medical attention:
Feeling dizzy, sleepy, tired, or weak
Upset stomach or vomiting
Dry mouth
Constipation
Reporting Side Effects
This is not an exhaustive list of possible side effects. 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 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
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 occurred in people taking seizure medications like this one. Seek medical help right away 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
- Throwing up
- Yellow skin or eyes
Neuroleptic malignant syndrome (NMS), a rare but potentially life-threatening condition, may occur. Seek medical help right away if you experience:
+ Fever
+ Muscle cramps or stiffness
+ Dizziness
+ Severe headache
+ Confusion
+ Change in thinking
+ Fast heartbeat
+ Abnormal heartbeat
+ Excessive sweating
Other Possible Side Effects
Like all medications, this drug may cause side effects. Many people experience no side effects or only mild ones. If you notice any of the following side effects or any other symptoms that bother you or do not go away, contact your doctor or seek medical attention:
Feeling dizzy, sleepy, tired, or weak
Upset stomach or vomiting
Dry mouth
Constipation
Reporting Side Effects
This is not an exhaustive list of possible side effects. 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, eyes, or genitals (signs of severe skin reactions like SJS/TEN). Seek immediate medical attention.
- Fever, chills, sore throat, mouth sores, unusual bruising or bleeding, pale skin, extreme tiredness (signs of blood problems). Contact your doctor immediately.
- Yellowing of the skin or eyes (jaundice), dark urine, persistent nausea/vomiting, severe stomach pain (signs of liver problems). Contact your doctor immediately.
- Swelling of the face, lips, tongue, or throat (angioedema). Seek immediate medical attention.
- Confusion, disorientation, severe dizziness, unsteadiness, or unusual muscle movements (signs of toxicity or hyponatremia).
- Increased seizures or changes in seizure pattern.
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. Be sure to describe the allergic reaction you experienced, including any symptoms that occurred.
If you have kidney disease, as this may affect how your body processes the medication.
A history of certain health conditions, such as bone marrow problems or porphyria, which may impact your ability to take this medication safely.
Any medications you are currently taking, including prescription and over-the-counter drugs, natural products, and vitamins. This is crucial because some medications, such as those used to treat hepatitis C, HIV, infections, and other conditions, may interact with this medication and should not be taken together.
* 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.
Please note that this is not an exhaustive list of all potential interactions or health problems that may affect your ability to take this medication. To ensure your safety, it is vital to discuss all of your medications, health conditions, and concerns with your doctor and pharmacist. Never start, stop, or change the dose of any medication without first consulting your doctor to confirm that it is safe to do so.
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances. Be sure to describe the allergic reaction you experienced, including any symptoms that occurred.
If you have kidney disease, as this may affect how your body processes the medication.
A history of certain health conditions, such as bone marrow problems or porphyria, which may impact your ability to take this medication safely.
Any medications you are currently taking, including prescription and over-the-counter drugs, natural products, and vitamins. This is crucial because some medications, such as those used to treat hepatitis C, HIV, infections, and other conditions, may interact with this medication and should not be taken together.
* 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.
Please note that this is not an exhaustive list of all potential interactions or health problems that may affect your ability to take this medication. To ensure your safety, it is vital to discuss all of your medications, health conditions, and concerns with your doctor and pharmacist. Never start, stop, or change the dose of any medication without first consulting your doctor to confirm that it is safe to do so.
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
Regular blood tests are necessary, as directed by your doctor. Additionally, schedule an eye exam as recommended by your doctor.
Interference with Lab Tests
This medication may affect certain laboratory test results. Inform all your healthcare providers and laboratory personnel that you are taking this medication.
Pregnancy Testing
This medication may cause false results in some pregnancy tests. Discuss this with your doctor if you are pregnant or suspect you may be pregnant.
Interactions with Other Substances
Before consuming alcohol, marijuana, or other forms of cannabis, or taking prescription or over-the-counter medications that may cause drowsiness, consult your doctor. If you regularly drink grapefruit juice or eat grapefruit, discuss this with your doctor as well.
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 discontinue the medication, your doctor will guide you on how to gradually stop taking it.
Seizure Management
If your seizures change or worsen after starting this medication, inform your doctor promptly.
Mental Health
Like other seizure medications, this drug may rarely increase the risk of suicidal thoughts or behaviors, particularly in individuals with a history of suicidal ideation. Monitor your mood and behavior, 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 behaviors, seek medical attention right away.
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
A rare but potentially life-threatening reaction called angioedema can occur with this medication. Symptoms include swelling of the hands, face, lips, eyes, tongue, or throat, difficulty breathing, swallowing, or unusual hoarseness. If you experience any of these symptoms, seek medical help immediately.
Special Considerations
If you are 65 or older, use this medication with caution, as you may be more susceptible to side effects.
This medication may affect fertility in men. Discuss this with your doctor if you are concerned about fathering a child.
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 are pregnant or become pregnant while taking this medication, inform your doctor immediately, as it may harm the unborn baby.
* If you are breastfeeding, consult 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
Regular blood tests are necessary, as directed by your doctor. Additionally, schedule an eye exam as recommended by your doctor.
Interference with Lab Tests
This medication may affect certain laboratory test results. Inform all your healthcare providers and laboratory personnel that you are taking this medication.
Pregnancy Testing
This medication may cause false results in some pregnancy tests. Discuss this with your doctor if you are pregnant or suspect you may be pregnant.
Interactions with Other Substances
Before consuming alcohol, marijuana, or other forms of cannabis, or taking prescription or over-the-counter medications that may cause drowsiness, consult your doctor. If you regularly drink grapefruit juice or eat grapefruit, discuss this with your doctor as well.
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 discontinue the medication, your doctor will guide you on how to gradually stop taking it.
Seizure Management
If your seizures change or worsen after starting this medication, inform your doctor promptly.
Mental Health
Like other seizure medications, this drug may rarely increase the risk of suicidal thoughts or behaviors, particularly in individuals with a history of suicidal ideation. Monitor your mood and behavior, 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 behaviors, seek medical attention right away.
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
A rare but potentially life-threatening reaction called angioedema can occur with this medication. Symptoms include swelling of the hands, face, lips, eyes, tongue, or throat, difficulty breathing, swallowing, or unusual hoarseness. If you experience any of these symptoms, seek medical help immediately.
Special Considerations
If you are 65 or older, use this medication with caution, as you may be more susceptible to side effects.
This medication may affect fertility in men. Discuss this with your doctor if you are concerned about fathering a child.
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 are pregnant or become pregnant while taking this medication, inform your doctor immediately, as it may harm the unborn baby.
* If you are breastfeeding, consult your doctor to discuss any potential risks to your baby.
Overdose Information
Overdose Symptoms:
- Dizziness, drowsiness, stupor, coma
- Nausea, vomiting
- Uncontrolled jerky eye movements (nystagmus)
- Unsteady gait (ataxia)
- Slurred speech
- Blurred vision, double vision
- Tremors, involuntary movements
- Seizures
- Respiratory depression
- Cardiac conduction disturbances (e.g., tachycardia, bradycardia, AV block)
- Hypotension or hypertension
What to Do:
Call 911 or your local emergency number immediately. For poison control, call 1-800-222-1222. Overdose management is supportive, including gastric lavage, activated charcoal, and monitoring of vital signs and cardiac function.
Drug Interactions
Contraindicated Interactions
- Monoamine Oxidase Inhibitors (MAOIs) (within 14 days of use)
- Nefazodone
- Delavirdine
- Boceprevir
- Telaprevir
Major Interactions
- Other CNS depressants (e.g., alcohol, benzodiazepines, opioids) - increased sedation
- Bone marrow suppressants (e.g., clozapine, methotrexate) - increased risk of hematologic toxicity
- Oral contraceptives - decreased efficacy of contraception
- Warfarin - decreased anticoagulant effect
- Lamotrigine, Valproic acid, Phenytoin, Phenobarbital - altered levels of both drugs
- CYP3A4 inhibitors (e.g., azole antifungals, macrolide antibiotics, grapefruit juice) - increased carbamazepine levels
- CYP3A4 inducers (e.g., rifampin, St. John's Wort) - decreased carbamazepine levels
- Immunosuppressants (e.g., cyclosporine, tacrolimus) - decreased levels of immunosuppressants
- Calcium channel blockers (e.g., felodipine, verapamil) - altered levels of both drugs
- Antidepressants (e.g., tricyclics, SSRIs) - altered levels of both drugs, increased risk of serotonin syndrome with some SSRIs
Moderate Interactions
- Diuretics (e.g., hydrochlorothiazide, furosemide) - increased risk of hyponatremia
- Lithium - increased neurotoxicity
- Thyroid hormones - decreased thyroid hormone levels
- Acetaminophen - increased risk of hepatotoxicity with chronic carbamazepine use
- Corticosteroids - decreased corticosteroid efficacy
Minor Interactions
- Not available
Monitoring
Baseline Monitoring
Complete Blood Count (CBC) with differential and platelet count
Rationale: To detect baseline hematologic abnormalities and monitor for aplastic anemia and agranulocytosis (Black Box Warning).
Timing: Prior to initiation of therapy.
Liver Function Tests (LFTs)
Rationale: To assess baseline hepatic function and monitor for liver injury.
Timing: Prior to initiation of therapy.
Renal Function Tests (BUN, Creatinine)
Rationale: To assess baseline renal function.
Timing: Prior to initiation of therapy.
Serum Electrolytes (especially Sodium)
Rationale: To assess baseline electrolyte balance and monitor for hyponatremia.
Timing: Prior to initiation of therapy.
HLA-B*1502 allele testing
Rationale: To identify patients of Asian ancestry at increased risk for Stevens-Johnson Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN).
Timing: Prior to initiation of therapy for patients of Asian ancestry.
Ophthalmologic examination
Rationale: To establish baseline and monitor for visual disturbances.
Timing: Prior to initiation of therapy.
Routine Monitoring
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 <3000/mm³ or ANC <1000/mm³ or Platelets <100,000/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 elevation (e.g., >3x ULN) or signs of liver injury.
Serum Sodium
Frequency: Periodically, especially in the 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.
Carbamazepine Serum Levels
Frequency: After 3-5 days of therapy, then periodically, especially with dose changes or suspected toxicity/non-adherence.
Target: 4-12 mcg/mL (therapeutic range)
Action Threshold: Adjust dose to maintain within therapeutic range or based on clinical response/toxicity.
Symptom Monitoring
- Rash, blistering, skin peeling (SJS/TEN)
- Fever, sore throat, mouth ulcers, easy bruising, unusual bleeding, petechiae (hematologic abnormalities)
- Yellowing of skin/eyes, dark urine, abdominal pain, nausea, vomiting (liver dysfunction)
- Dizziness, drowsiness, ataxia, blurred vision, diplopia, nystagmus (CNS effects, toxicity)
- Confusion, disorientation, lethargy, seizures (hyponatremia, toxicity)
- Swelling of face, lips, tongue (angioedema)
Special Patient Groups
Pregnancy
Carbamazepine is associated with an increased risk of major congenital malformations, particularly neural tube defects (e.g., spina bifida), and other developmental abnormalities. It should only be used during pregnancy if the potential benefit outweighs the risk to the fetus. Folic acid supplementation (at least 4 mg/day) is recommended for women of childbearing potential and during pregnancy.
Trimester-Specific Risks:
First Trimester:
Highest risk for neural tube defects and other major congenital malformations (e.g., craniofacial defects, cardiovascular malformations, hypospadias).
Second Trimester:
Continued risk of developmental effects, though major structural malformations are less likely to originate in this trimester.
Third Trimester:
Risk of withdrawal symptoms in the neonate (e.g., irritability, tremors, feeding difficulties) and potential for bleeding disorders due to vitamin K deficiency.
Lactation
Carbamazepine and its active metabolite are excreted into breast milk. While generally considered moderately safe (L3), infants should be monitored for adverse effects such as drowsiness, poor feeding, weight gain, and liver toxicity. Breastfeeding may be considered with careful monitoring of the infant.
Infant Risk:
Risk level L3 (Moderately Safe). Monitor for sedation, poor feeding, weight gain, and signs of liver dysfunction.
Pediatric Use
Dosing is weight-based and age-dependent. Children may metabolize carbamazepine faster than adults, requiring higher mg/kg doses. Close monitoring for adverse effects, including hematologic and dermatologic reactions, is crucial. Chewable tablets are often preferred for pediatric patients.
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 and CNS side effects is important.
Clinical Information
Clinical Pearls
- Carbamazepine exhibits autoinduction of its own metabolism, meaning its half-life shortens over time with chronic use. This necessitates dose adjustments and careful therapeutic drug monitoring.
- Therapeutic drug monitoring (TDM) is crucial for carbamazepine, with a target serum concentration of 4-12 mcg/mL. However, clinical response and tolerability should guide dosing, not solely drug levels.
- HLA-B*1502 allele testing is strongly recommended for patients of Asian ancestry prior to initiation due to a significantly increased risk of severe dermatologic reactions (SJS/TEN). If positive, carbamazepine is generally contraindicated unless benefits clearly outweigh risks.
- The chewable tablet formulation may have different absorption characteristics compared to conventional or extended-release forms. Ensure patients understand how to properly administer the chewable form (chew thoroughly).
- Carbamazepine is a potent enzyme inducer, leading to numerous significant drug-drug interactions, particularly with oral contraceptives, warfarin, and many other medications metabolized by CYP450 enzymes. Always review concomitant medications.
- Hyponatremia is a common side effect, especially in the elderly or those on diuretics. Monitor serum sodium levels periodically.
Alternative Therapies
- For Epilepsy: Valproic acid, Lamotrigine, Levetiracetam, Oxcarbazepine, Phenytoin, Topiramate, Gabapentin, Pregabalin.
- For Trigeminal Neuralgia: Oxcarbazepine, Gabapentin, Pregabalin, Baclofen, Phenytoin.
- For Bipolar Disorder: Lithium, Valproic acid, Lamotrigine, Atypical antipsychotics (e.g., olanzapine, quetiapine).
Cost & Coverage
Average Cost:
Varies widely, typically $20-$100+ 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 use, never share your medication with others or take someone else's medication. This medication is accompanied by a Medication Guide, which provides crucial information for patients. Please read this guide carefully and review it again whenever you receive a refill of this medication. 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. Be prepared to provide detailed information about the overdose, including the substance taken, the amount, and the time it occurred.