Carbamazepine 100mg ER Capsules
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
Mar 1997
DEA Schedule
Not Controlled
Overview
What is this medicine?
Carbamazepine is a medication used to treat certain types of seizures (epilepsy), nerve pain (trigeminal neuralgia), and bipolar disorder. 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. You can take this medication with or without food. Swallow the capsule whole - do not chew, break, or crush it. If you have trouble swallowing the capsule, you can sprinkle its contents onto a soft food like applesauce. However, do not chew the mixture. Instead, swallow it immediately and follow with a glass of water or juice.
Storing and Disposing of Your Medication
Store your medication at room temperature, away from light and moisture. Keep it in a dry place, such as a closet or drawer, and avoid storing it in the bathroom. Always keep your medications in a safe and secure location, out of the reach of children and pets. When you no longer need this medication or it has expired, 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. If you are unsure about the best way to dispose of your medication, consult your pharmacist or look into local drug take-back programs.
Missing a Dose
If you miss a dose, take it as soon as you remember. However, if it is 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 use this medication correctly, follow your doctor's instructions and read all the information provided. You can take this medication with or without food. Swallow the capsule whole - do not chew, break, or crush it. If you have trouble swallowing the capsule, you can sprinkle its contents onto a soft food like applesauce. However, do not chew the mixture. Instead, swallow it immediately and follow with a glass of water or juice.
Storing and Disposing of Your Medication
Store your medication at room temperature, away from light and moisture. Keep it in a dry place, such as a closet or drawer, and avoid storing it in the bathroom. Always keep your medications in a safe and secure location, out of the reach of children and pets. When you no longer need this medication or it has expired, 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. If you are unsure about the best way to dispose of your medication, consult your pharmacist or look into local drug take-back programs.
Missing a Dose
If you miss a dose, take it as soon as you remember. However, if it is 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 with food to reduce stomach upset and improve absorption.
- Do not crush, chew, or open extended-release capsules; swallow them whole.
- Avoid grapefruit and grapefruit juice, as they 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.
- Be aware of increased sensitivity to sunlight; use sunscreen and wear protective clothing.
- Carry a medical alert card or wear a medical alert bracelet indicating 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 (BID) or 400 mg once daily (QD) for ER. Increase by 200 mg/day at weekly intervals. Maintenance 800-1200 mg/day in divided doses. Bipolar Disorder: Initial 200 mg BID (ER). Increase by 200 mg/day at weekly intervals. Maintenance 400-1600 mg/day in divided doses. Trigeminal Neuralgia: Initial 200 mg QD (ER). Increase by 200 mg/day until pain relief. Maintenance 400-800 mg/day.
Dose Range:
200 - 1600 mg
Condition-Specific Dosing:
epilepsy:
Initial 200 mg BID or 400 mg QD (ER), titrate to 800-1200 mg/day.
bipolarDisorder:
Initial 200 mg BID (ER), titrate to 400-1600 mg/day.
trigeminalNeuralgia:
Initial 200 mg QD (ER), titrate to 400-800 mg/day.
Pediatric Dosing
Neonatal:
Not established
Infant:
Not established
Child:
Epilepsy (6-12 years): Initial 100 mg BID or 200 mg QD (ER). Increase by 100 mg/day at weekly intervals. Maintenance 400-800 mg/day. Epilepsy (>12 years): Same as adult dosing.
Adolescent:
Epilepsy (>12 years): Same as adult dosing.
Dose Adjustments
Renal Impairment:
Mild:
No specific adjustment, monitor for adverse effects.
Moderate:
No specific adjustment, monitor for adverse effects.
Severe:
Use with caution, monitor serum levels and clinical response. Dose reduction may be necessary.
Dialysis:
Carbamazepine is not significantly dialyzable. Administer usual dose after dialysis. Monitor levels.
Hepatic Impairment:
Mild:
Use with caution, monitor LFTs and serum levels.
Moderate:
Use with caution, monitor LFTs and serum levels. Dose reduction may be necessary.
Severe:
Contraindicated in severe hepatic impairment. Use with extreme caution, if at all, and monitor 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 may also affect calcium channels and GABAergic systems, contributing to its anticonvulsant and mood-stabilizing effects.
Pharmacokinetics
Absorption:
Bioavailability:
Approximately 80% (variable, influenced by formulation and food)
Tmax:
Extended-release capsules: 3-12 hours
FoodEffect:
Food can increase the rate and extent of absorption for ER formulations, reducing variability.
Distribution:
Vd:
0.8-1.9 L/kg
ProteinBinding:
75-80%
CnssPenetration:
Yes
Elimination:
HalfLife:
Initial: 25-65 hours; Chronic use (autoinduction): 12-17 hours
Clearance:
Variable, increases with autoinduction
ExcretionRoute:
Renal (72%), Fecal (28%)
Unchanged:
2-3% (renal)
Pharmacodynamics
OnsetOfAction:
Days to weeks for full therapeutic effect due to slow titration and autoinduction.
PeakEffect:
Variable, depends on titration and autoinduction.
DurationOfAction:
Extended-release formulation designed for 12-24 hour duration.
Confidence:
High
Safety & Warnings
BLACK BOX WARNING
SERIOUS DERMATOLOGIC REACTIONS AND HLA-B*1502 ALLELE: Serious and sometimes fatal dermatologic reactions, including toxic epidermal necrolysis (TEN) and Stevens-Johnson syndrome (SJS), have been reported with carbamazepine therapy. These reactions are estimated to occur in 1 to 6 per 10,000 new users in countries with mainly Caucasian populations, but the risk in some Asian populations is about 10 times higher. Studies in patients of Chinese ancestry have shown a strong association between the risk of developing SJS/TEN and the presence of HLA-B*1502 allele. Prior to initiating carbamazepine, patients of Asian ancestry should be screened for the presence of HLA-B*1502 allele. Aplastic Anemia and Agranulocytosis: Aplastic anemia and agranulocytosis have been reported in association with the use of carbamazepine. An estimated 1 in 200,000 patients treated with carbamazepine may develop agranulocytosis, and an estimated 1 in 500,000 patients may develop aplastic anemia. Patients should be advised of the early toxic signs and symptoms of a potential hematologic problem (e.g., fever, sore throat, mouth ulcers, easy bruising, petechial or purpuric hemorrhage) and instructed to report them to the physician immediately. Complete pretreatment blood counts (including platelet count, reticulocytes, and serum iron) should be obtained and repeated at regular intervals.
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
Change in speech
Hallucinations (seeing or hearing things that are not there)
Change 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
- Vomiting
- 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 unusual symptoms, contact your doctor or seek medical attention:
Feeling dizzy, sleepy, tired, or weak
Upset stomach or vomiting
Dry mouth
Constipation
Reporting Side Effects
This list is not exhaustive, and you may experience other 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
Change in speech
Hallucinations (seeing or hearing things that are not there)
Change 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
- Vomiting
- 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 unusual symptoms, contact your doctor or seek medical attention:
Feeling dizzy, sleepy, tired, or weak
Upset stomach or vomiting
Dry mouth
Constipation
Reporting Side Effects
This list is not exhaustive, and you may experience other 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 rash, blistering, or peeling skin (especially with fever, sore throat, or swollen glands)
- Yellowing of skin or eyes (jaundice), dark urine, severe stomach pain, nausea, or vomiting
- Unusual bleeding or bruising, pinpoint red spots on skin (petechiae), pale skin, extreme tiredness, fever, chills, sore throat, mouth sores (signs of blood problems)
- Swelling of the face, lips, tongue, or throat (angioedema)
- Confusion, disorientation, severe headache, increased seizures, or unusual drowsiness (signs of low sodium)
- Changes in vision (e.g., blurred vision, double vision)
- Severe dizziness, loss of coordination, or unsteadiness
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.
If you have 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. This is crucial because certain medications, such as those used to treat hepatitis C, HIV, infections, and other conditions, should not be taken with this drug.
* 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 vital to provide your doctor and pharmacist with a comprehensive list of all your medications, including prescription and OTC drugs, natural products, and vitamins, as well as any health problems you have. This will help them determine whether it is safe for you to take this medication with your other medications and health conditions. Never start, stop, or change the dose of any medication without first consulting 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.
If you have 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. This is crucial because certain medications, such as those used to treat hepatitis C, HIV, infections, and other conditions, should not be taken with this drug.
* 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 vital to provide your doctor and pharmacist with a comprehensive list of all your medications, including prescription and OTC drugs, natural products, and vitamins, as well as any health problems you have. This will help them determine whether it is safe for you to take this medication with your other medications and health conditions. Never start, stop, or change the dose of any medication without first consulting your doctor.
Precautions & Cautions
Important Warnings and Precautions
It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication. This will help ensure that you receive proper care and avoid any potential interactions.
Caution with Daily Activities
Until you know how this medication affects you, avoid driving and engaging in other activities that require alertness. This will help prevent accidents and ensure your safety.
Monitoring and Follow-up
Regular blood tests and eye exams are crucial while taking this medication. Follow your doctor's instructions for scheduling these tests, and discuss any concerns or questions you may have.
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 to ensure accurate test results.
Pregnancy Tests and Contraception
This medication may cause false results in some pregnancy tests. If you are pregnant or think you may be pregnant, consult your doctor. Additionally, if you are using birth control pills or other hormone-based contraception, you may need to use an alternative method, such as a condom, to prevent pregnancy.
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. Grapefruit juice and grapefruit can also interact with this medication, so discuss your consumption with your doctor.
Stopping the Medication
Do not stop taking this medication abruptly without consulting your doctor, as this may increase your 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 you experience changes in your seizures or they worsen after starting this medication, consult your doctor. Like other seizure medications, this medication may rarely increase the risk of suicidal thoughts or actions, especially in people with a history of suicidal behavior. Monitor your mood and behavior, and seek immediate medical attention if you experience any new or worsening symptoms, such as depression, anxiety, or panic attacks.
Cardiovascular Risks
This medication may cause heart problems, including heart failure and abnormal heartbeats, which can be fatal. Seek immediate medical attention if you experience a fast, slow, or irregular heartbeat, severe dizziness, shortness of breath, significant weight gain, or swelling in your arms or legs.
Rare but Serious Reactions
In rare cases, this medication can cause a severe reaction called angioedema, which can be life-threatening. Symptoms include swelling of the hands, face, lips, eyes, tongue, or throat, difficulty breathing, swallowing, or speaking, and unusual hoarseness. Seek immediate medical attention if you experience any of these symptoms.
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 also affect fertility in men, so discuss this with your doctor. If you are pregnant or breastfeeding, consult your doctor to discuss the 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. This will help ensure that you receive proper care and avoid any potential interactions.
Caution with Daily Activities
Until you know how this medication affects you, avoid driving and engaging in other activities that require alertness. This will help prevent accidents and ensure your safety.
Monitoring and Follow-up
Regular blood tests and eye exams are crucial while taking this medication. Follow your doctor's instructions for scheduling these tests, and discuss any concerns or questions you may have.
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 to ensure accurate test results.
Pregnancy Tests and Contraception
This medication may cause false results in some pregnancy tests. If you are pregnant or think you may be pregnant, consult your doctor. Additionally, if you are using birth control pills or other hormone-based contraception, you may need to use an alternative method, such as a condom, to prevent pregnancy.
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. Grapefruit juice and grapefruit can also interact with this medication, so discuss your consumption with your doctor.
Stopping the Medication
Do not stop taking this medication abruptly without consulting your doctor, as this may increase your 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 you experience changes in your seizures or they worsen after starting this medication, consult your doctor. Like other seizure medications, this medication may rarely increase the risk of suicidal thoughts or actions, especially in people with a history of suicidal behavior. Monitor your mood and behavior, and seek immediate medical attention if you experience any new or worsening symptoms, such as depression, anxiety, or panic attacks.
Cardiovascular Risks
This medication may cause heart problems, including heart failure and abnormal heartbeats, which can be fatal. Seek immediate medical attention if you experience a fast, slow, or irregular heartbeat, severe dizziness, shortness of breath, significant weight gain, or swelling in your arms or legs.
Rare but Serious Reactions
In rare cases, this medication can cause a severe reaction called angioedema, which can be life-threatening. Symptoms include swelling of the hands, face, lips, eyes, tongue, or throat, difficulty breathing, swallowing, or speaking, and unusual hoarseness. Seek immediate medical attention if you experience any of these symptoms.
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 also affect fertility in men, so discuss this with your doctor. If you are pregnant or breastfeeding, consult your doctor to discuss the potential risks to your baby.
Overdose Information
Overdose Symptoms:
- Dizziness, drowsiness, stupor, coma
- Ataxia (loss of coordination), nystagmus (involuntary eye movements)
- Tremor, restlessness, agitation, convulsions
- Nausea, vomiting
- Urinary retention
- Respiratory depression
- Tachycardia, hypotension, cardiac conduction disturbances
What to Do:
Seek immediate medical attention. Call 911 or Poison Control at 1-800-222-1222. Treatment is supportive and symptomatic, including gastric lavage, activated charcoal, and close monitoring of vital signs.
Drug Interactions
Contraindicated Interactions
- MAO inhibitors (within 14 days)
- Nefazodone
- Delavirdine
- Boceprevir
- Telaprevir
- Voriconazole
- Isocarboxazid
- Phenelzine
- Tranylcypromine
- Selegiline (oral)
- Linezolid
Major Interactions
- Other anticonvulsants (e.g., phenytoin, phenobarbital, valproic acid - altered levels of both drugs)
- Oral contraceptives (reduced efficacy)
- Warfarin (reduced anticoagulant effect)
- Antipsychotics (e.g., clozapine, haloperidol, quetiapine - reduced levels)
- Antidepressants (e.g., tricyclic antidepressants, SSRIs - altered levels)
- Calcium channel blockers (e.g., verapamil, diltiazem - increased carbamazepine levels)
- Macrolide antibiotics (e.g., erythromycin, clarithromycin - increased carbamazepine levels)
- Azole antifungals (e.g., ketoconazole, itraconazole - increased carbamazepine levels)
- Protease inhibitors (e.g., ritonavir, indinavir - altered levels)
- Grapefruit juice (increased carbamazepine levels)
- Immunosuppressants (e.g., cyclosporine, tacrolimus - reduced levels)
- Corticosteroids (reduced efficacy)
- Thyroid hormones (reduced efficacy)
Moderate Interactions
- Diuretics (e.g., hydrochlorothiazide - risk of hyponatremia)
- Lithium (increased neurotoxicity)
- Neuromuscular blockers (e.g., pancuronium - reduced effect)
- Acetaminophen (reduced efficacy, increased hepatotoxicity risk)
- Theophylline (reduced levels)
- Bupropion (reduced levels, increased seizure risk)
Minor Interactions
- Not available
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 of therapy
Liver Function Tests (LFTs)
Rationale: To establish baseline and monitor for hepatic dysfunction.
Timing: Prior to initiation of therapy
Renal Function Tests (BUN, Creatinine)
Rationale: To establish baseline and monitor for renal impairment.
Timing: Prior to initiation of therapy
Electrolytes (especially Sodium)
Rationale: To establish baseline 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
HLA-A*3101 allele testing
Rationale: To identify patients of European, Japanese, or Native American ancestry at increased risk for SJS/TEN, DRESS, or maculopapular eruption.
Timing: Consider prior to initiation of therapy for patients of these ancestries
Thyroid Function Tests (TFTs)
Rationale: To establish baseline, as carbamazepine can affect thyroid hormones.
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: Within normal limits
Action Threshold: Discontinue if WBC < 3000/mm³ or ANC < 1000/mm³ or platelet count < 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 elevations (e.g., >3x ULN) or signs of liver injury.
Serum Sodium
Frequency: Periodically, especially in the first few months and in elderly patients 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 to guide dose adjustments, especially during titration, with drug interactions, or if toxicity/lack of efficacy is suspected.
Target: 4-12 mcg/mL (therapeutic range)
Action Threshold: Adjust dose if outside therapeutic range or if clinical signs of toxicity/subtherapeutic levels are present.
Thyroid Function Tests (TFTs)
Frequency: Periodically, especially if symptoms of hypothyroidism develop.
Target: Within normal limits
Action Threshold: Not available
Symptom Monitoring
- Rash, blistering, skin peeling (Stevens-Johnson Syndrome, Toxic Epidermal Necrolysis)
- Fever, sore throat, mouth ulcers, easy bruising, unusual bleeding, pallor, fatigue (hematologic abnormalities)
- Yellowing of skin or eyes, dark urine, abdominal pain, nausea, vomiting (hepatic dysfunction)
- Confusion, disorientation, lethargy, severe headache, increased seizure frequency (hyponatremia, CNS effects)
- Swelling of face, lips, tongue, or throat (angioedema)
- Joint pain, muscle aches, swollen lymph nodes, eosinophilia (Drug Reaction with Eosinophilia and Systemic Symptoms - DRESS)
- Vision changes (e.g., blurred vision, diplopia)
- Dizziness, ataxia, drowsiness
Special Patient Groups
Pregnancy
Carbamazepine is classified as Pregnancy Category D due to evidence of human fetal risk. It 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 developmental delays. Use during pregnancy should only be considered if the potential benefit outweighs the potential risk to the fetus. Folic acid supplementation (e.g., 4 mg/day) is recommended for women of childbearing potential and during pregnancy.
Trimester-Specific Risks:
First Trimester:
Highest risk for major congenital malformations, especially neural tube defects, if exposed during the first trimester.
Second Trimester:
Continued risk of developmental effects; potential for growth restriction.
Third Trimester:
Risk of withdrawal symptoms (e.g., seizures, irritability, feeding difficulties) in the neonate if exposed late in pregnancy.
Lactation
Carbamazepine and its active metabolite are excreted into breast milk. The American Academy of Pediatrics considers carbamazepine compatible with breastfeeding, but caution is advised. Monitor the infant for signs of adverse effects.
Infant Risk:
L3 (Moderately Safe). Potential for infant drowsiness, poor feeding, weight gain issues, and rare reports of liver dysfunction or blood dyscrasias. Monitor infant for sedation, irritability, rash, and adequate weight gain. Serum levels in the infant may be monitored if concerns arise.
Pediatric Use
Dosing is weight-based and age-dependent. Children may metabolize carbamazepine faster than adults, requiring higher doses per kg or more frequent dosing. Close monitoring of serum levels and adverse effects is crucial. Risk of dermatologic reactions (SJS/TEN) is higher in children with HLA-B*1502 allele.
Geriatric Use
Start with lower doses and titrate slowly due to increased sensitivity to adverse effects (e.g., dizziness, ataxia, hyponatremia). Elderly patients may have reduced renal and hepatic function, affecting drug clearance. Increased risk of hyponatremia and falls.
Clinical Information
Clinical Pearls
- Carbamazepine is a potent autoinducer of its own metabolism, meaning its half-life decreases over time with chronic use. This necessitates careful titration and monitoring of serum levels.
- Always screen patients of Asian ancestry for the HLA-B*1502 allele before initiating carbamazepine due to the significantly increased risk of SJS/TEN.
- Advise patients to take ER capsules whole and not to crush or chew them, as this can lead to rapid release and potential toxicity.
- Counsel patients on the importance of reporting any signs of rash, fever, sore throat, or unusual bruising/bleeding immediately.
- Due to numerous drug interactions, a thorough medication review is essential before starting carbamazepine and whenever new medications are added or discontinued.
- Hyponatremia is a common side effect, especially in elderly patients or those on diuretics; monitor sodium levels regularly.
Alternative Therapies
- For Epilepsy: Valproic acid, Lamotrigine, Levetiracetam, Phenytoin, Oxcarbazepine, Topiramate, Zonisamide, Gabapentin, Pregabalin.
- For Bipolar Disorder: Lithium, Valproic acid, Lamotrigine, Atypical antipsychotics (e.g., Quetiapine, Olanzapine, Aripiprazole).
- For Trigeminal Neuralgia: Oxcarbazepine, Gabapentin, Pregabalin, Baclofen, Phenytoin.
Cost & Coverage
Average Cost:
Price range varies widely by pharmacy and formulation (e.g., $30-$200+) per 30 capsules (100mg ER)
Generic Available:
Yes
Insurance Coverage:
Tier 1 or Tier 2 (Generic), Tier 3 or higher (Brand)
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 for guidance.
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 medication taken, the quantity, and the time it occurred, to facilitate prompt and appropriate treatment.
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 for guidance.
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 medication taken, the quantity, and the time it occurred, to facilitate prompt and appropriate treatment.