Lamotrigine ER 25mg Tablets
WARNING: Severe skin reactions may happen with this drug. These include Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and other serious reactions. Sometimes, body organs may also be affected. These reactions can be deadly. Get medical help right away if you have signs like red, swollen, blistered, or peeling skin; red or irritated eyes; sores in your mouth, throat, nose, eyes, genitals, or any areas of skin; fever; chills; body aches; shortness of breath; or swollen glands. The chance of a skin reaction is raised in children between 2 and 17 years old. It may also be raised if you take valproic acid or divalproex sodium with this drug, if you start taking this drug at too high of a dose, or if your dose is raised too fast. Skin reactions have also happened without any of these. Talk with your doctor.Most cases of skin reactions have happened within 2 to 8 weeks of starting this drug, but some show up after longer treatment like 6 months. Talk with the doctor.This drug is not approved for use in children younger than 13 years old. Talk with the doctor. @ COMMON USES: It is used to help control certain kinds of seizures.It may be given to you for other reasons. Talk with the doctor.
Drug Class
Anticonvulsant, Mood Stabilizer
Pharmacologic Class
Phenyltriazine derivative, Voltage-gated sodium channel blocker
Pregnancy Category
C
FDA Approved
Jun 2009
DEA Schedule
Not Controlled
Overview
What is this medicine?
Lamotrigine ER is an extended-release medication used to help control seizures in people with epilepsy and to help stabilize mood in people with bipolar disorder. It works by calming overactive nerve signals in the brain. The 'ER' means it releases the medicine slowly over time, so you usually take it once a day.
How to Use This Medicine
Taking Your Medication Correctly
To get the most benefit from your medication, follow your doctor's instructions carefully. Read all the information provided to you and follow the instructions closely. You can take this medication with or without food. Continue taking your medication as directed by your doctor or healthcare provider, even if you start to feel well.
Important Administration Instructions
Swallow the medication whole; do not chew, break, or crush it.
If you have difficulty swallowing, consult your doctor for guidance.
Do not alter your dose or stop taking this medication without consulting your doctor, as this may lead to seizures.
If you need to stop taking this medication, your doctor will instruct you on how to gradually taper off the dose to minimize the risk of side effects.
If you stop taking this medication and need to restart, your doctor may recommend starting at a lower dose and gradually increasing it.
Storing and Disposing of Your Medication
Store your medication at room temperature, protected from light and moisture.
Keep your medication in a dry place, away from the bathroom.
Store all medications in a safe location, out of the reach of children and pets.
Dispose of unused or expired medications properly. Do not flush them down the toilet or pour them down the drain unless instructed to do so by your pharmacist.
Check with your pharmacist for guidance on the best way to dispose of your medication, and consider participating in local drug take-back programs.
What to Do If You Miss a Dose
If you miss a dose, take it as soon as you remember.
If it is close to the time for your next 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 dose.
To get the most benefit from your medication, follow your doctor's instructions carefully. Read all the information provided to you and follow the instructions closely. You can take this medication with or without food. Continue taking your medication as directed by your doctor or healthcare provider, even if you start to feel well.
Important Administration Instructions
Swallow the medication whole; do not chew, break, or crush it.
If you have difficulty swallowing, consult your doctor for guidance.
Do not alter your dose or stop taking this medication without consulting your doctor, as this may lead to seizures.
If you need to stop taking this medication, your doctor will instruct you on how to gradually taper off the dose to minimize the risk of side effects.
If you stop taking this medication and need to restart, your doctor may recommend starting at a lower dose and gradually increasing it.
Storing and Disposing of Your Medication
Store your medication at room temperature, protected from light and moisture.
Keep your medication in a dry place, away from the bathroom.
Store all medications in a safe location, out of the reach of children and pets.
Dispose of unused or expired medications properly. Do not flush them down the toilet or pour them down the drain unless instructed to do so by your pharmacist.
Check with your pharmacist for guidance on the best way to dispose of your medication, and consider participating in local drug take-back programs.
What to Do If You Miss a Dose
If you miss a dose, take it as soon as you remember.
If it is close to the time for your next 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 dose.
Lifestyle & Tips
- Take exactly as prescribed, usually once daily at the same time each day. Do not crush, chew, or split the extended-release tablets.
- Do not stop taking this medication suddenly, as it can lead to increased seizure frequency or other withdrawal symptoms. Any dose changes should be made under the guidance of your doctor.
- Be aware of the risk of serious skin rash. Contact your doctor immediately if you develop any rash, fever, swollen glands, or facial swelling.
- Avoid activities requiring mental alertness, such as driving or operating machinery, until you know how this medication affects you, as it can cause dizziness or drowsiness.
- Report any changes in mood, behavior, or suicidal thoughts to your doctor immediately.
- Use sun protection as lamotrigine may cause photosensitivity.
- If you are a woman of childbearing potential, discuss contraception options with your doctor, as oral contraceptives can affect lamotrigine levels.
Available Forms & Alternatives
Available Strengths:
- Lamotrigine 150mg Tablets
- Lamotrigine 200mg Tablets
- Lamotrigine 25mg Tablets
- Lamotrigine 100mg Tablets
- Lamotrigine 25mg Chew/disprsbl Tab
- Lamotrigine 5mg Chew/disprsbl Tab
- Lamotrigine ER 50mg Tablets
- Lamotrigine ER 200mg Tablets
- Lamotrigine ER 100mg Tablets
- Lamotrigine 300mg ER Tablets
- Lamotrigine ER 25mg Tablets
- Lamotrigine ODT 25mg Tablets
- Lamotrigine ODT 50mg Tablets
- Lamotrigine Orge Strt Kit25/100mg
- Lamotrigine Blue Starter Kit 25mg T
- Lamotrigine Green Str Kit 25/100mg
- Lamotrigine ODT 100mg Tablets
- Lamotrigine ODT 200mg Tablets
- Lamotrigine ER 250mg Tablets
- Lamotrigine ODT 25-50-100mg Tb Kit
Dosing & Administration
Adult Dosing
Standard Dose:
Highly variable, requires slow titration based on concomitant medications. Initial dose for patients not taking valproate or enzyme-inducing AEDs is typically 25 mg once daily for 2 weeks, then 50 mg once daily for 2 weeks, then 100 mg once daily for 1 week, then 150 mg once daily for 1 week, then 200 mg once daily. Further increases to 300-400 mg/day may be needed.
Dose Range:
25 - 400 mg
Condition-Specific Dosing:
concomitant_valproate:
Initial dose 25 mg every other day for 2 weeks, then 25 mg once daily for 2 weeks, then 50 mg once daily for 1 week, then 75 mg once daily for 1 week, then 100 mg once daily. Max 200 mg/day.
concomitant_enzyme_inducing_aeds_without_valproate:
Initial dose 50 mg once daily for 2 weeks, then 100 mg once daily for 2 weeks, then 200 mg once daily for 1 week, then 300 mg once daily for 1 week, then 400 mg once daily. Max 600 mg/day.
Pediatric Dosing
Neonatal:
Not established
Infant:
Not established
Child:
Not established for ER formulation under 13 years.
Adolescent:
For partial-onset seizures (âĨ13 years): Dosing similar to adults, based on concomitant medications and titration schedule. Initial dose 25 mg once daily for 2 weeks (if not on valproate or enzyme-inducing AEDs).
Dose Adjustments
Renal Impairment:
Mild:
No specific adjustment needed, but caution advised.
Moderate:
No specific adjustment needed, but caution advised.
Severe:
Reduced maintenance doses may be effective; use with caution. Consider lower initial doses and slower titration.
Dialysis:
Supplemental doses after dialysis are generally not required as lamotrigine is minimally dialyzed. Use with caution and monitor clinical response.
Hepatic Impairment:
Mild:
No specific adjustment needed.
Moderate:
Reduce initial, escalation, and maintenance doses by approximately 25%.
Severe:
Reduce initial, escalation, and maintenance doses by approximately 50%. Use with extreme caution and monitor closely.
Pharmacology
Mechanism of Action
Lamotrigine is a phenyltriazine derivative that stabilizes neuronal membranes and inhibits the release of excitatory neurotransmitters (primarily glutamate and aspartate) by blocking voltage-sensitive sodium channels. This action prevents repetitive firing of neurons and reduces the propagation of seizure activity. It also has weak effects on voltage-gated calcium channels.
Pharmacokinetics
Absorption:
Bioavailability:
Approximately 98% (oral)
Tmax:
Approximately 4-12 hours (extended-release formulation)
FoodEffect:
Food does not significantly affect the rate or extent of absorption.
Distribution:
Vd:
Approximately 0.97-1.36 L/kg
ProteinBinding:
Approximately 55%
CnssPenetration:
Yes
Elimination:
HalfLife:
Approximately 25-33 hours (monotherapy, can be significantly altered by concomitant medications: ~15 hours with enzyme inducers, ~59 hours with valproate)
Clearance:
Approximately 0.3-0.5 mL/min/kg
ExcretionRoute:
Renal (approximately 94% as metabolites, 2% unchanged drug)
Unchanged:
Approximately 2%
Pharmacodynamics
OnsetOfAction:
Gradual (due to slow titration to minimize rash risk)
PeakEffect:
Achieved after reaching stable maintenance dose, typically weeks to months after initiation.
DurationOfAction:
Once daily dosing due to extended-release formulation and half-life.
Safety & Warnings
BLACK BOX WARNING
Serious skin rashes requiring hospitalization and discontinuation of treatment have been reported, including Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN). The incidence of these rashes, which have resulted in deaths, is approximately 0.3% to 0.8% in pediatric patients (aged 2 to 16 years) and 0.08% to 0.3% in adults. The risk of serious rash is increased by coadministration with valproate, exceeding the recommended initial dose, or exceeding the recommended dose escalation.
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 immediately or seek emergency medical attention:
Signs of an allergic reaction, such as:
+ Rash or hives
+ Itching or red, swollen, blistered, or peeling skin (with or without fever)
+ Wheezing or tightness in the chest or throat
+ Difficulty breathing, swallowing, or talking
+ Unusual hoarseness or swelling of the mouth, face, lips, tongue, or throat
Signs of kidney problems, including:
+ Inability to urinate or changes in urine output
+ Blood in the urine or significant weight gain
Signs of liver problems, such as:
+ Dark urine
+ Fatigue or decreased appetite
+ Upset stomach or stomach pain
+ Light-colored stools or vomiting
+ Yellow skin or eyes
Shortness of breath, significant weight gain, or swelling in the arms or legs
Severe muscle pain or weakness
Severe joint pain or swelling
Changes in vision
Chest pain or pressure
Abnormal heartbeat (fast, slow, or irregular)
Severe dizziness or fainting
Balance problems or difficulty controlling eye movements
Flu-like symptoms
Painful or irregular menstrual periods
Low blood cell counts, which can increase the risk of bleeding, infection, or anemia. If you experience any of the following, contact your doctor right away:
+ Fever, chills, or sore throat
+ Unexplained bruising or bleeding
+ Feeling extremely tired or weak
Hemophagocytic lymphohistiocytosis (HLH), a potentially life-threatening immune system disorder. If you experience any of the following, contact your doctor immediately:
+ Fever
+ Swollen glands
+ Rash
+ Seizures
+ Confusion or decreased alertness
+ Balance problems or difficulty walking
Other Possible Side Effects
Like all medications, this drug can cause side effects. While many people may not experience any side effects or only minor ones, it's essential to discuss any concerns with your doctor. If you experience any of the following side effects, contact your doctor if they bother you or persist:
Dizziness, drowsiness, fatigue, or weakness
Constipation, diarrhea, stomach pain, upset stomach, vomiting, or decreased appetite
Shakiness or tremors
Difficulty sleeping
Nose or throat irritation
Weight loss
Dry mouth
* Back pain
This is not an exhaustive list of possible side effects. If you have questions or concerns about side effects, consult your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you notice any of the following symptoms, contact your doctor immediately or seek emergency medical attention:
Signs of an allergic reaction, such as:
+ Rash or hives
+ Itching or red, swollen, blistered, or peeling skin (with or without fever)
+ Wheezing or tightness in the chest or throat
+ Difficulty breathing, swallowing, or talking
+ Unusual hoarseness or swelling of the mouth, face, lips, tongue, or throat
Signs of kidney problems, including:
+ Inability to urinate or changes in urine output
+ Blood in the urine or significant weight gain
Signs of liver problems, such as:
+ Dark urine
+ Fatigue or decreased appetite
+ Upset stomach or stomach pain
+ Light-colored stools or vomiting
+ Yellow skin or eyes
Shortness of breath, significant weight gain, or swelling in the arms or legs
Severe muscle pain or weakness
Severe joint pain or swelling
Changes in vision
Chest pain or pressure
Abnormal heartbeat (fast, slow, or irregular)
Severe dizziness or fainting
Balance problems or difficulty controlling eye movements
Flu-like symptoms
Painful or irregular menstrual periods
Low blood cell counts, which can increase the risk of bleeding, infection, or anemia. If you experience any of the following, contact your doctor right away:
+ Fever, chills, or sore throat
+ Unexplained bruising or bleeding
+ Feeling extremely tired or weak
Hemophagocytic lymphohistiocytosis (HLH), a potentially life-threatening immune system disorder. If you experience any of the following, contact your doctor immediately:
+ Fever
+ Swollen glands
+ Rash
+ Seizures
+ Confusion or decreased alertness
+ Balance problems or difficulty walking
Other Possible Side Effects
Like all medications, this drug can cause side effects. While many people may not experience any side effects or only minor ones, it's essential to discuss any concerns with your doctor. If you experience any of the following side effects, contact your doctor if they bother you or persist:
Dizziness, drowsiness, fatigue, or weakness
Constipation, diarrhea, stomach pain, upset stomach, vomiting, or decreased appetite
Shakiness or tremors
Difficulty sleeping
Nose or throat irritation
Weight loss
Dry mouth
* Back pain
This is not an exhaustive list of possible side effects. If you have questions or concerns about side effects, consult your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Seek Immediate Medical Attention If You Experience:
- Any new skin rash (especially if it spreads, blisters, or involves mucous membranes like mouth, eyes, nose, genitals)
- Fever, swollen glands, or facial swelling (signs of a serious allergic reaction)
- Sore throat, mouth sores, or unusual bruising/bleeding
- Yellowing of skin or eyes (jaundice)
- Severe fatigue or weakness
- Worsening seizures or new types of seizures
- Changes in mood or behavior, including new or worsening depression, anxiety, agitation, panic attacks, insomnia, irritability, hostility, impulsivity, severe restlessness, or thoughts of self-harm.
- Signs of aseptic meningitis (headache, fever, nausea, vomiting, stiff neck, rash, sensitivity to light)
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, any of its components, or other substances, such as foods or drugs. Be sure to describe the allergic reaction you experienced, including any symptoms that occurred.
If you are currently taking dofetilide, as this may interact with the medication.
To ensure your safety, it is crucial to provide your doctor and pharmacist with a comprehensive list of:
All prescription and over-the-counter (OTC) medications you are taking
Any natural products or vitamins you are using
* Your complete medical history, including any health problems you have
This will enable your doctor to verify that it is safe for you to take this medication in conjunction with your other medications and health conditions. Never start, stop, or adjust the dosage of any medication without first consulting your doctor.
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, any of its components, or other substances, such as foods or drugs. Be sure to describe the allergic reaction you experienced, including any symptoms that occurred.
If you are currently taking dofetilide, as this may interact with the medication.
To ensure your safety, it is crucial to provide your doctor and pharmacist with a comprehensive list of:
All prescription and over-the-counter (OTC) medications you are taking
Any natural products or vitamins you are using
* Your complete medical history, including any health problems you have
This will enable your doctor to verify that it is safe for you to take this medication in conjunction with your other medications and health conditions. Never start, stop, or adjust the dosage of any medication without first consulting your doctor.
Precautions & Cautions
Important Warnings and Cautions
When taking this medication, it is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, about your treatment. This will help ensure your safety and prevent potential interactions with other medications.
Caution with Daily Activities
Avoid driving and engaging in activities that require alertness until you understand how this medication affects you. It may take several weeks to experience the full effects of the medication.
Monitoring and Lab Tests
Regular blood tests will be necessary, as directed by your doctor. Be sure to discuss any concerns or questions with your doctor. Additionally, inform all your healthcare providers and laboratory personnel that you are taking this medication, as it may affect certain lab test results.
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 with 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 behavior. If you experience new or worsening symptoms such as depression, anxiety, restlessness, irritability, panic attacks, or mood changes, contact your doctor immediately. If you have suicidal thoughts or actions, seek medical attention right away.
Risk of Aseptic Meningitis
This medication may increase the risk of a severe brain condition called aseptic meningitis. If you experience symptoms such as headache, fever, chills, severe nausea or vomiting, stiff neck, rash, sensitivity to light, drowsiness, or confusion, contact your doctor immediately.
Medication Verification
To avoid confusion, always verify that you have the correct medication, as some drugs may have similar names or appearances. If you notice any changes in the medication's shape, color, size, or packaging, consult with your pharmacist.
Heart Problems
If you have a history of abnormal heart rhythms, heart failure, or other heart conditions, discuss your treatment with your doctor. Abnormal heartbeats can increase the risk of sudden death in individuals with pre-existing heart problems.
Pediatric Use
When administering this medication to children, use caution, as the risk of certain side effects may be higher in pediatric patients.
Birth Control and Hormone Interactions
If you are taking birth control pills or other hormone-based contraceptives, inform your doctor, as these medications may affect the levels of this medication in your body. Additionally, the effectiveness of birth control pills may be reduced when taking this medication, increasing the risk of pregnancy. Consider using alternative forms of birth control, such as condoms, to prevent pregnancy.
Pregnancy and Breastfeeding
If you are pregnant, plan to become pregnant, or are breastfeeding, discuss the benefits and risks of this medication with your doctor.
Seizure Management
If your seizures change or worsen after starting this medication, consult with your doctor to adjust your treatment plan as needed.
When taking this medication, it is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, about your treatment. This will help ensure your safety and prevent potential interactions with other medications.
Caution with Daily Activities
Avoid driving and engaging in activities that require alertness until you understand how this medication affects you. It may take several weeks to experience the full effects of the medication.
Monitoring and Lab Tests
Regular blood tests will be necessary, as directed by your doctor. Be sure to discuss any concerns or questions with your doctor. Additionally, inform all your healthcare providers and laboratory personnel that you are taking this medication, as it may affect certain lab test results.
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 with 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 behavior. If you experience new or worsening symptoms such as depression, anxiety, restlessness, irritability, panic attacks, or mood changes, contact your doctor immediately. If you have suicidal thoughts or actions, seek medical attention right away.
Risk of Aseptic Meningitis
This medication may increase the risk of a severe brain condition called aseptic meningitis. If you experience symptoms such as headache, fever, chills, severe nausea or vomiting, stiff neck, rash, sensitivity to light, drowsiness, or confusion, contact your doctor immediately.
Medication Verification
To avoid confusion, always verify that you have the correct medication, as some drugs may have similar names or appearances. If you notice any changes in the medication's shape, color, size, or packaging, consult with your pharmacist.
Heart Problems
If you have a history of abnormal heart rhythms, heart failure, or other heart conditions, discuss your treatment with your doctor. Abnormal heartbeats can increase the risk of sudden death in individuals with pre-existing heart problems.
Pediatric Use
When administering this medication to children, use caution, as the risk of certain side effects may be higher in pediatric patients.
Birth Control and Hormone Interactions
If you are taking birth control pills or other hormone-based contraceptives, inform your doctor, as these medications may affect the levels of this medication in your body. Additionally, the effectiveness of birth control pills may be reduced when taking this medication, increasing the risk of pregnancy. Consider using alternative forms of birth control, such as condoms, to prevent pregnancy.
Pregnancy and Breastfeeding
If you are pregnant, plan to become pregnant, or are breastfeeding, discuss the benefits and risks of this medication with your doctor.
Seizure Management
If your seizures change or worsen after starting this medication, consult with your doctor to adjust your treatment plan as needed.
Overdose Information
Overdose Symptoms:
- Ataxia (loss of coordination)
- Nystagmus (involuntary eye movements)
- Increased seizures
- Decreased consciousness
- Coma
- QRS prolongation (cardiac conduction abnormality)
What to Do:
Seek immediate medical attention or call 911. For poison control, call 1-800-222-1222. Management is primarily supportive, including gastric lavage, activated charcoal, and close monitoring of vital signs and cardiac function. There is no specific antidote.
Drug Interactions
Major Interactions
- Valproate (increases lamotrigine levels significantly, requiring dose reduction)
- Carbamazepine, Phenytoin, Phenobarbital, Primidone (decrease lamotrigine levels, requiring dose increase)
- Estrogen-containing oral contraceptives (decrease lamotrigine levels, requiring dose increase and potential for breakthrough seizures)
Moderate Interactions
- Rifampin (decreases lamotrigine levels)
- Lopinavir/ritonavir (decreases lamotrigine levels)
- Atazanavir/ritonavir (decreases lamotrigine levels)
- Dofetilide (potential for increased dofetilide levels, though clinical significance unclear)
- Risperidone (lamotrigine may decrease risperidone levels)
Minor Interactions
- Paracetamol (acetaminophen) (may slightly decrease lamotrigine levels with chronic high-dose use)
- Bupropion (may slightly increase lamotrigine levels)
Monitoring
Baseline Monitoring
Complete Blood Count (CBC)
Rationale: To establish baseline and monitor for rare but serious hematologic reactions (e.g., aplastic anemia, agranulocytosis).
Timing: Prior to initiation
Liver Function Tests (LFTs)
Rationale: To establish baseline and monitor for rare but serious hepatic dysfunction.
Timing: Prior to initiation
Renal Function Tests (Creatinine, BUN)
Rationale: To establish baseline, especially important for dose adjustments in severe renal impairment.
Timing: Prior to initiation
Skin Examination
Rationale: To establish baseline and educate patient on signs of serious rash.
Timing: Prior to initiation
Routine Monitoring
Clinical monitoring for rash (e.g., Stevens-Johnson Syndrome, Toxic Epidermal Necrolysis)
Frequency: Daily during titration, then regularly
Target: Absence of rash
Action Threshold: Any new rash should prompt immediate discontinuation and medical evaluation.
Monitoring for signs of hypersensitivity syndrome (Drug Reaction with Eosinophilia and Systemic Symptoms - DRESS)
Frequency: Regularly, especially during first 8 weeks
Target: Absence of fever, lymphadenopathy, facial swelling, organ involvement
Action Threshold: Any signs should prompt immediate discontinuation and medical evaluation.
Seizure frequency and severity (for epilepsy)
Frequency: Regularly, at each visit
Target: Reduction or elimination of seizures
Action Threshold: Worsening seizures or lack of efficacy may require dose adjustment or alternative therapy.
Mood stability (for bipolar disorder)
Frequency: Regularly, at each visit
Target: Stabilization of mood, reduction in depressive or manic episodes
Action Threshold: Worsening mood symptoms may require dose adjustment or alternative therapy.
Adverse effects (e.g., dizziness, ataxia, blurred vision, headache, nausea)
Frequency: Regularly, at each visit
Target: Tolerable side effect profile
Action Threshold: Intolerable side effects may require dose adjustment or discontinuation.
Therapeutic Drug Monitoring (TDM)
Frequency: Not routinely recommended, but may be considered in specific situations (e.g., suspected non-adherence, toxicity, pregnancy, significant drug interactions, renal/hepatic impairment)
Target: Generally 3-14 mcg/mL (though correlation with efficacy/toxicity is variable)
Action Threshold: Levels outside target range, especially if correlated with clinical symptoms or lack of efficacy.
Symptom Monitoring
- New or worsening skin rash (especially blistering, peeling, or involving mucous membranes)
- Fever
- Swollen lymph nodes (lymphadenopathy)
- Facial swelling
- Sore throat
- Mouth sores
- Unusual bruising or bleeding
- Yellowing of skin or eyes (jaundice)
- Dark urine
- Severe fatigue
- Worsening seizures
- Changes in mood or behavior (e.g., new or worsening depression, suicidal thoughts, anxiety, agitation, panic attacks, insomnia, irritability, hostility, impulsivity, severe restlessness, hypomania, mania)
- Unexplained muscle pain or weakness
- Signs of aseptic meningitis (headache, fever, nausea, vomiting, stiff neck, rash, sensitivity to light)
Special Patient Groups
Pregnancy
Lamotrigine is classified as Pregnancy Category C. It should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. There is an increased risk of oral clefts (cleft lip/palate) in infants exposed to lamotrigine during the first trimester, though the absolute risk is low. Levels of lamotrigine may decrease significantly during pregnancy, requiring dose adjustments.
Trimester-Specific Risks:
First Trimester:
Increased risk of oral clefts (cleft lip/palate). Monitor lamotrigine levels and adjust dose as needed.
Second Trimester:
Lamotrigine levels may continue to decrease. Monitor and adjust dose.
Third Trimester:
Lamotrigine levels may continue to decrease. Monitor and adjust dose. Consider higher doses of folic acid supplementation.
Lactation
Lamotrigine is excreted into breast milk. The concentration in breast milk can be significant, potentially leading to infant serum concentrations that are 50% of maternal levels. Monitor breastfed infants for adverse effects such as rash, drowsiness, poor feeding, and apnea. Weigh the benefits of breastfeeding against the potential risks to the infant.
Infant Risk:
L3 (Moderately Safe) - Monitor infant for rash, drowsiness, poor feeding, apnea. Consider therapeutic drug monitoring in the infant if concerns arise.
Pediatric Use
Lamotrigine ER is approved for partial-onset seizures in patients 13 years and older. Safety and efficacy in pediatric patients younger than 13 years have not been established for the ER formulation. The risk of serious rash is higher in pediatric patients (2-16 years) compared to adults.
Geriatric Use
Use with caution in elderly patients. Start with lower doses and titrate more slowly, as elderly patients may be more sensitive to the effects of the drug and may have age-related decreases in renal or hepatic function. Monitor for adverse effects, particularly dizziness and ataxia, which can increase fall risk.
Clinical Information
Clinical Pearls
- The most critical aspect of lamotrigine therapy is slow dose titration to minimize the risk of serious skin rash. Never accelerate the titration schedule.
- Patients must be educated to report any rash immediately and discontinue the drug if a rash develops, unless clearly non-drug related.
- Concomitant medications, especially valproate and enzyme-inducing AEDs (like carbamazepine, phenytoin), significantly alter lamotrigine levels and require specific dose adjustments.
- Oral contraceptives containing estrogen can decrease lamotrigine levels, potentially leading to loss of seizure control or mood stabilization. Dose adjustments may be needed.
- Lamotrigine ER is taken once daily and should not be crushed, chewed, or split.
- While TDM is not routinely recommended, it can be very useful in specific situations such as pregnancy, suspected non-adherence, or when managing complex drug interactions.
Alternative Therapies
- Levetiracetam (Keppra)
- Topiramate (Topamax)
- Oxcarbazepine (Trileptal)
- Carbamazepine (Tegretol)
- Valproate (Depakote)
- Zonisamide (Zonegran)
- Gabapentin (Neurontin)
- Pregabalin (Lyrica)
Cost & Coverage
Average Cost:
$30 - $150 per 30 tablets (generic 25mg 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's 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. Please read this guide carefully and review it again whenever you receive a refill. If you have any questions or concerns about this medication, don't hesitate to 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 amount, and the time it occurred.