Dosage Form: tablet, film coated, extended release
FULL PRESCRIBING INFORMATION
LAMICTAL® XR™ can cause serious rashes requiring hospitalization and discontinuation of treatment. The incidence of these rashes, which have included Stevens-Johnson syndrome, is approximately 0.8% (8 per 1,000) in pediatric patients (aged 2 to 16 years) receiving immediate-release lamotrigine as adjunctive therapy for epilepsy and 0.3% (3 per 1,000) in adults on adjunctive therapy for epilepsy. In a prospectively followed cohort of 1,983 pediatric patients (aged 2 to 16 years) with epilepsy taking adjunctive immediate-release lamotrigine, there was 1 rash-related death. Lamictal XR is not approved for patients less than 13 years of age. In worldwide postmarketing experience, rare cases of toxic epidermal necrolysis and/or rash-related death have been reported in adult and pediatric patients, but their numbers are too few to permit a precise estimate of the rate.
The risk of serious rash caused by treatment with Lamictal XR is not expected to differ from that with immediate-release lamotrigine. However, the relatively limited treatment experience with Lamictal XR makes it difficult to characterize the frequency and risk of serious rashes caused by treatment with Lamictal XR.
Other than age, there are as yet no factors identified that are known to predict the risk of occurrence or the severity of rash caused by Lamictal XR. There are suggestions, yet to be proven, that the risk of rash may also be increased by (1) coadministration of Lamictal XR with valproate (includes valproic acid and divalproex sodium), (2) exceeding the recommended initial dose of Lamictal XR, or (3) exceeding the recommended dose escalation for Lamictal XR. However, cases have occurred in the absence of these factors.
Nearly all cases of life-threatening rashes caused by immediate-release lamotrigine have occurred within 2 to 8 weeks of treatment initiation. However, isolated cases have occurred after prolonged treatment (e.g., 6 months). Accordingly, duration of therapy cannot be relied upon as means to predict the potential risk heralded by the first appearance of a rash.
Although benign rashes are also caused by Lamictal XR, it is not possible to predict reliably which rashes will prove to be serious or life threatening. Accordingly, Lamictal XR should ordinarily be discontinued at the first sign of rash, unless the rash is clearly not drug related. Discontinuation of treatment may not prevent a rash from becoming life threatening or permanently disabling or disfiguring [see Warnings and Precautions (5.1)].
Indications and Usage for Lamictal XR
Adjunctive Therapy
Lamictal XR is indicated as adjunctive therapy for primary generalized tonic-clonic (PGTC) seizures and partial onset seizures with or without secondary generalization in patients ≥13 years of age.
1.2 Monotherapy
Lamictal XR is indicated for conversion to monotherapy in patients ≥13 years of age with partial seizures who are receiving treatment with a single antiepileptic drug (AED).
Safety and effectiveness of Lamictal XR have not been established (1) as initial monotherapy or (2) for simultaneous conversion to monotherapy from two or more concomitant AEDs.
Limitation of Use
Safety and effectiveness of Lamictal XR for use in patients less than 13 years of age have not been established.
Lamictal XR Dosage and Administration
Lamictal XR Extended-Release Tablets are taken once daily, with or without food. Tablets must be swallowed whole and must not be chewed, crushed, or divided.
General Dosing Considerations
Rash: There are suggestions, yet to be proven, that the risk of severe, potentially life-threatening rash may be increased by (1) coadministration of Lamictal XR with valproate, (2) exceeding the recommended initial dose of Lamictal XR, or (3) exceeding the recommended dose escalation for Lamictal XR. However, cases have occurred in the absence of these factors [see Boxed Warning]. Therefore, it is important that the dosing recommendations be followed closely.
The risk of nonserious rash may be increased when the recommended initial dose and/or the rate of dose escalation for Lamictal XR is exceeded and in patients with a history of allergy or rash to other AEDs.
Lamictal XR Patient Titration Kits provide Lamictal XR at doses consistent with the recommended titration schedule for the first 5 weeks of treatment, based upon concomitant medications for patients with partial onset seizures, and are intended to help reduce the potential for rash. The use of Lamictal XR Patient Titration Kits is recommended for appropriate patients who are starting or restarting LAMICTAL XR [see How Supplied/Storage and Handling (16)].
It is recommended that Lamictal XR not be restarted in patients who discontinued due to rash associated with prior treatment with lamotrigine, unless the potential benefits clearly outweigh the risks. If the decision is made to restart a patient who has discontinued Lamictal XR, the need to restart with the initial dosing recommendations should be assessed. The greater the interval of time since the previous dose, the greater consideration should be given to restarting with the initial dosing recommendations. If a patient has discontinued lamotrigine for a period of more than 5 half-lives, it is recommended that initial dosing recommendations and guidelines be followed. The half-life of lamotrigine is affected by other concomitant medications [see Clinical Pharmacology (12.3)].
Lamictal XR Added to Drugs Known to Induce or Inhibit Glucuronidation: Drugs other than those listed in the Clinical Pharmacology section [see Clinical Pharmacology (12.3)] have not been systematically evaluated in combination with lamotrigine. Because lamotrigine is metabolized predominantly by glucuronic acid conjugation, drugs that are known to induce or inhibit glucuronidation may affect the apparent clearance of lamotrigine and doses of Lamictal XR may require adjustment based on clinical response.
Target Plasma Levels: A therapeutic plasma concentration range has not been established for lamotrigine. Dosing of Lamictal XR should be based on therapeutic response [see Clinical Pharmacology (12.3)].
Women Taking Estrogen-Containing Oral Contraceptives:Starting Lamictal XR in Women Taking Estrogen-Containing Oral Contraceptives: Although estrogen-containing oral contraceptives have been shown to increase the clearance of lamotrigine [see Clinical Pharmacology (12.3)], no adjustments to the recommended dose-escalation guidelines for Lamictal XR should be necessary solely based on the use of estrogen-containing oral contraceptives. Therefore, dose escalation should follow the recommended guidelines for initiating adjunctive therapy with Lamictal XR based on the concomitant AED or other concomitant medications (see Table 1). See below for adjustments to maintenance doses of Lamictal XR in women taking estrogen-containing oral contraceptives.
Adjustments to the Maintenance Dose of Lamictal XR in Women Taking Estrogen-Containing Oral Contraceptives:
(1) Taking Estrogen-Containing Oral Contraceptives: For women not taking carbamazepine, phenytoin, phenobarbital, primidone, or other drugs such as rifampin that induce lamotrigine glucuronidation [see Drug Interactions (7), Clinical Pharmacology (12.3)], the maintenance dose of Lamictal XR will in most cases need to be increased by as much as 2-fold over the recommended target maintenance dose in order to maintain a consistent lamotrigine plasma level [see Clinical Pharmacology (12.3)].
(2) Starting Estrogen-Containing Oral Contraceptives: In women taking a stable dose of Lamictal XR and not taking carbamazepine, phenytoin, phenobarbital, primidone, or other drugs such as rifampin that induce lamotrigine glucuronidation [see Drug Interactions (7), Clinical Pharmacology (12.3)], the maintenance dose will in most cases need to be increased by as much as 2-fold in order to maintain a consistent lamotrigine plasma level. The dose increases should begin at the same time that the oral contraceptive is introduced and continue, based on clinical response, no more rapidly than 50 to 100 mg/day every week. Dose increases should not exceed the recommended rate (see Table 1) unless lamotrigine plasma levels or clinical response support larger increases. Gradual transient increases in lamotrigine plasma levels may occur during the week of inactive hormonal preparation (pill-free week), and these increases will be greater if dose increases are made in the days before or during the week of inactive hormonal preparation. Increased lamotrigine plasma levels could result in additional adverse reactions, such as dizziness, ataxia, and diplopia. If adverse reactions attributable to Lamictal XR consistently occur during the pill-free week, dose adjustments to the overall maintenance dose may be necessary. Dose adjustments limited to the pill-free week are not recommended. For women taking Lamictal XR in addition to carbamazepine, phenytoin, phenobarbital, primidone, or other drugs such as rifampin that induce lamotrigine glucuronidation [see Drug Interactions (7), Clinical Pharmacology (12.3)], no adjustment to the dose of Lamictal XR should be necessary.
(3) Stopping Estrogen-Containing Oral Contraceptives: For women not taking carbamazepine, phenytoin, phenobarbital, primidone, or other drugs such as rifampin that induce lamotrigine glucuronidation [see Drug Interactions (7), Clinical Pharmacology (12.3)], the maintenance dose of Lamictal XR will in most cases need to be decreased by as much as 50% in order to maintain a consistent lamotrigine plasma level. The decrease in dose of Lamictal XR should not exceed 25% of the total daily dose per week over a 2-week period, unless clinical response or lamotrigine plasma levels indicate otherwise [see Clinical Pharmacology (12.3)]. For women taking Lamictal XR in addition to carbamazepine, phenytoin, phenobarbital, primidone, or other drugs such as rifampin that induce lamotrigine glucuronidation [see Drug Interactions (7), Clinical Pharmacology (12.3)], no adjustment to the dose of Lamictal XR should be necessary.
Women and Other Hormonal Contraceptive Preparations or Hormone Replacement Therapy: The effect of other hormonal contraceptive preparations or hormone replacement therapy on the pharmacokinetics of lamotrigine has not been systematically evaluated. It has been reported that ethinylestradiol, not progestogens, increased the clearance of lamotrigine up to 2-fold, and the progestin-only pills had no effect on lamotrigine plasma levels. Therefore, adjustments to the dosage of Lamictal XR in the presence of progestogens alone will likely not be needed.
Patients With Hepatic Impairment: Experience in patients with hepatic impairment is limited. Based on a clinical pharmacology study in 24 patients with mild, moderate, and severe liver impairment [see Use in Specific Populations (8.6), Clinical Pharmacology (12.3)], the following general recommendations can be made. No dosage adjustment is needed in patients with mild liver impairment. Initial, escalation, and maintenance doses should generally be reduced by approximately 25% in patients with moderate and severe liver impairment without ascites and 50% in patients with severe liver impairment with ascites. Escalation and maintenance doses may be adjusted according to clinical response.
Patients With Renal Impairment: Initial doses of Lamictal XR should be based on patients’ concomitant medications (see Table 1); reduced maintenance doses may be effective for patients with significant renal impairment [see Use in Specific Populations (8.7), Clinical Pharmacology (12.3)]. Few patients with severe renal impairment have been evaluated during chronic treatment with immediate-release lamotrigine. Because there is inadequate experience in this population, Lamictal XR should be used with caution in these patients.
Discontinuation Strategy: For patients receiving Lamictal XR in combination with other AEDs, a re-evaluation of all AEDs in the regimen should be considered if a change in seizure control or an appearance or worsening of adverse reactions is observed.
If a decision is made to discontinue therapy with Lamictal XR, a step-wise reduction of dose over at least 2 weeks (approximately 50% per week) is recommended unless safety concerns require a more rapid withdrawal [see Warnings and Precautions (5.8)].
Discontinuing carbamazepine, phenytoin, phenobarbital, primidone, or other drugs such as rifampin that induce lamotrigine glucuronidation should prolong the half-life of lamotrigine; discontinuing valproate should shorten the half-life of lamotrigine.
Adjunctive Therapy for Primary Generalized Tonic-Clonic and Partial Onset Seizures
This section provides specific dosing recommendations for patients ≥13 years of age. Specific dosing recommendations are provided depending upon concomitant AED or other concomitant medications.
| For Patients TAKING Valproatea | For Patients NOT TAKING Carbamazepine, Phenytoin, Phenobarbital, Primidone,b or Valproatea | For Patients TAKING Carbamazepine, Phenytoin, Phenobarbital, or Primidoneb and NOT TAKING Valproatea | |
| Weeks 1 and 2 | 25 mg every other day | 25 mg every day | 50 mg every day |
| Weeks 3 and 4 | 25 mg every day | 50 mg every day | 100 mg every day |
| Week 5 | 50 mg every day | 100 mg every day | 200 mg every day |
| Week 6 | 100 mg every day | 150 mg every day | 300 mg every day |
| Week 7 | 150 mg every day | 200 mg every day | 400 mg every day |
| Maintenance range (week 8 and onward) | 200 to 250 mg every dayc | 300 to 400 mg every dayc | 400 to 600 mg every dayc |
aValproate has been shown to inhibit glucuronidation and decrease the apparent clearance of lamotrigine [see Drug Interactions (7), Clinical Pharmacology (12.3)].
bThese drugs induce lamotrigine glucuronidation and increase clearance [see Drug Interactions (7), Clinical Pharmacology (12.3)]. Other drugs that have similar effects include estrogen-containing oral contraceptives [see Drug Interactions (7), Clinical Pharmacology (12.3)]. Dosing recommendations for oral contraceptives can be found in General Dosing Considerations [see Dosage and Administration (2.1)]. Patients on rifampin, or other drugs that induce lamotrigine glucuronidation and increase clearance, should follow the same dosing titration/maintenance regimen as that used with anticonvulsants that have this effect.
cDose increases at week 8 or later should not exceed 100 mg daily at weekly intervals.
2.3 Conversion From Adjunctive Therapy to Monotherapy
The goal of the transition regimen is to attempt to maintain seizure control while mitigating the risk of serious rash associated with the rapid titration of Lamictal XR.
The recommended maintenance dosage range of Lamictal XR as monotherapy is 250 to 300 mg given once daily.
The recommended initial dose and subsequent dose escalations for Lamictal XR should not be exceeded [see Boxed Warning].
Conversion From Adjunctive Therapy With Carbamazepine, Phenytoin, Phenobarbital, or Primidone to Monotherapy With Lamictal XR: After achieving a dosage of 500 mg/day of Lamictal XR using the guidelines in Table 1, the concomitant enzyme-inducing AED should be withdrawn by 20% decrements each week over a 4-week period. Two weeks after completion of withdrawal of the enzyme-inducing AED, the dosage of LAMICTAL XR may be decreased no faster than 100 mg/day each week to achieve the monotherapy maintenance dosage range of 250 to 300 mg/day.
The regimen for the withdrawal of the concomitant AED is based on experience gained in the controlled monotherapy clinical trial using immediate-release lamotrigine.
Conversion From Adjunctive Therapy With Valproate to Monotherapy With Lamictal XR: The conversion regimen involves the 4 steps outlined in Table 2.
| Lamictal XR | Valproate | |
| Step 1 | Achieve a dosage of 150 mg/day according to guidelines in Table 1. | Maintain established stable dose. |
| Step 2 | Maintain at 150 mg/day. | Decrease dosage by decrements no greater than 500 mg/day/week to 500 mg/day and then maintain for 1 week. |
| Step 3 | Increase to 200 mg/day. | Simultaneously decrease to 250 mg/day and maintain for 1 week. |
| Step 4 | Increase to 250 or 300 mg/day. | Discontinue. |
Conversion From Adjunctive Therapy With Antiepileptic Drugs Other Than Carbamazepine, Phenytoin, Phenobarbital, Primidone, or Valproate to Monotherapy With Lamictal XR: After achieving a dosage of 250 to 300 mg/day of Lamictal XR using the guidelines in Table 1, the concomitant AED should be withdrawn by 20% decrements each week over a 4-week period. No adjustment to the monotherapy dose of Lamictal XR is needed.
Conversion From Immediate-Release Lamotrigine Tablets to Lamictal XR
Patients may be converted directly from immediate-release lamotrigine to Lamictal XR Extended-Release Tablets. The initial dose of Lamictal XR should match the total daily dose of immediate-release lamotrigine. However, some subjects on concomitant enzyme-inducing agents may have lower plasma levels of lamotrigine on conversion and should be monitored [see Clinical Pharmacology (12.3)].
Following conversion to Lamictal XR, all patients (but especially those on drugs that induce lamotrigine glucuronidation) should be closely monitored for seizure control [see Drug Interactions (7)]. Depending on the therapeutic response after conversion, the total daily dose may need to be adjusted within the recommended dosing instructions (Table 1).
Dosage Forms and Strengths
Extended-Release Tablets
25 mg, yellow with white center, round, biconvex, film-coated tablets printed with “LAMICTAL” and “XR 25.”
50 mg, green with white center, round, biconvex, film-coated tablets printed with “LAMICTAL” and “XR 50.”
100 mg, orange with white center, round, biconvex, film-coated tablets printed with “LAMICTAL” and “XR 100.”
200 mg, blue with white center, round, biconvex, film-coated tablets printed with “LAMICTAL” and “XR 200.”
250 mg, purple with white center, caplet-shaped, film-coated tablets printed with “LAMICTAL” and “XR 250.”
300 mg, gray with white center, caplet-shaped, film-coated tablets printed with “LAMICTAL” and “XR 300.”
Potential Medication Errors
Patients should be strongly advised to visually inspect their tablets to verify that they are receiving Lamictal XR, as opposed to other medications, and that they are receiving the correct formulation of lamotrigine each time they fill their prescription. Depictions of the Lamictal XR tablets can be found in the Medication Guide.
Contraindications
Lamictal XR is contraindicated in patients who have demonstrated hypersensitivity (e.g., rash, angioedema, acute urticaria, extensive pruritus, mucosal ulceration) to the drug or its ingredients [see Boxed Warning, Warnings and Precautions (5.1, 5.2)].
Warnings and Precautions
Serious Skin Rashes
The risk of serious rash caused by treatment with Lamictal XR is not expected to differ from that with immediate-release lamotrigine [see Boxed Warning]. However, the relatively limited treatment experience with Lamictal XR makes it difficult to characterize the frequency and risk of serious rashes caused by treatment with Lamictal XR.
Pediatric Population: The incidence of serious rash associated with hospitalization and discontinuation of immediate-release lamotrigine in a prospectively followed cohort of pediatric patients (aged 2 to 16 years) with epilepsy receiving adjunctive therapy with immediate-release lamotrigine was approximately 0.8% (16 of 1,983). When 14 of these cases were reviewed by 3 expert dermatologists, there was considerable disagreement as to their proper classification. To illustrate, one dermatologist considered none of the cases to be Stevens-Johnson syndrome; another assigned 7 of the 14 to this diagnosis. There was 1 rash-related death in this 1,983-patient cohort. Additionally, there have been rare cases of toxic epidermal necrolysis with and without permanent sequelae and/or death in US and foreign postmarketing experience.
There is evidence that the inclusion of valproate in a multidrug regimen increases the risk of serious, potentially life-threatening rash in pediatric patients. In pediatric patients who used valproate concomitantly, 1.2% (6 of 482) experienced a serious rash compared with 0.6% (6 of 952) patients not taking valproate.
Lamictal XR is not approved in patients less than 13 years of age.
Adult Population: Serious rash associated with hospitalization and discontinuation of immediate-release lamotrigine occurred in 0.3% (11 of 3,348) of adult patients who received immediate-release lamotrigine in premarketing clinical trials of epilepsy. In worldwide postmarketing experience, rare cases of rash-related death have been reported, but their numbers are too few to permit a precise estimate of the rate.
Among the rashes leading to hospitalization were Stevens-Johnson syndrome, toxic epidermal necrolysis, angioedema, and those associated with multiorgan hypersensitivity [see Warnings and Precautions (5.2)].
There is evidence that the inclusion of valproate in a multidrug regimen increases the risk of serious, potentially life-threatening rash in adults. Specifically, of 584 patients administered immediate-release lamotrigine with valproate in epilepsy clinical trials, 6 (1%) were hospitalized in association with rash; in contrast, 4 (0.16%) of 2,398 clinical trial patients and volunteers administered immediate-release lamotrigine in the absence of valproate were hospitalized.
Patients With History of Allergy or Rash to Other Antiepileptic Drugs: The risk of nonserious rash may be increased when the recommended initial dose and/or the rate of dose escalation for LAMICTAL XR is exceeded and in patients with a history of allergy or rash to other AEDs.
5.2 Multiorgan Hypersensitivity Reactions and Organ Failure
Multiorgan hypersensitivity reactions, also known as Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS), have occurred with LAMICTAL. Some have been fatal or life threatening. DRESS typically, although not exclusively, presents with fever, rash, and/or lymphadenopathy in association with other organ system involvement, such as hepatitis, nephritis, hematologic abnormalities, myocarditis, or myositis, sometimes resembling an acute viral infection. Eosinophilia is often present. This disorder is variable in its expression and other organ systems not noted here may be involved.
Fatalities associated with acute multiorgan failure and various degrees of hepatic failure have been reported in 2 of 3,796 adult patients and 4 of 2,435 pediatric patients who received LAMICTAL in epilepsy clinical trials. Rare fatalities from multiorgan failure have also been reported in postmarketing use.
Isolated liver failure without rash or involvement of other organs has also been reported with LAMICTAL.
It is important to note that early manifestations of hypersensitivity (e.g., fever, lymphadenopathy) may be present even though a rash is not evident. If such signs or symptoms are present, the patient should be evaluated immediately. Lamictal XR should be discontinued if an alternative etiology for the signs or symptoms cannot be established.
Prior to initiation of treatment with Lamictal XR, the patient should be instructed that a rash or other signs or symptoms of hypersensitivity (e.g., fever, lymphadenopathy) may herald a serious medical event and that the patient should report any such occurrence to a physician immediately.
Blood Dyscrasias
There have been reports of blood dyscrasias with immediate-release lamotrigine that may or may not be associated with multiorgan hypersensitivity (also known as DRESS) [see Warnings and Precautions (5.2)]. These have included neutropenia, leukopenia, anemia, thrombocytopenia, pancytopenia, and, rarely, aplastic anemia and pure red cell aplasia.
Suicidal Behavior and Ideation
AEDs, including Lamictal XR, increase the risk of suicidal thoughts or behavior in patients taking these drugs for any indication. Patients treated with any AED for any indication should be monitored for the emergence or worsening of depression, suicidal thoughts or behavior, and/or any unusual changes in mood or behavior.
Pooled analyses of 199 placebo-controlled clinical trials (monotherapy and adjunctive therapy) of 11 different AEDs showed that patients randomized to one of the AEDs had approximately twice the risk (adjusted Relative Risk 1.8, 95% CI:1.2, 2.7) of suicidal thinking or behavior compared to patients randomized to placebo. In these trials, which had a median treatment duration of 12 weeks, the estimated incidence of suicidal behavior or ideation among 27,863 AED-treated patients was 0.43%, compared to 0.24% among 16,029 placebo-treated patients, representing an increase of approximately 1 case of suicidal thinking or behavior for every 530 patients treated. There were 4 suicides in drug-treated patients in the trials and none in placebo-treated patients, but the number of events is too small to allow any conclusion about drug effect on suicide.
The increased risk of suicidal thoughts or behavior with AEDs was observed as early as 1 week after starting treatment with AEDs and persisted for the duration of treatment assessed. Because most trials included in the analysis did not extend beyond 24 weeks, the risk of suicidal thoughts or behavior beyond 24 weeks could not be assessed.
The risk of suicidal thoughts or behavior was generally consistent among drugs in the data analyzed. The finding of increased risk with AEDs of varying mechanism of action and across a range of indications suggests that the risk applies to all AEDs used for any indication. The risk did not vary substantially by age (5 to 100 years) in the clinical trials analyzed.
Table 3 shows absolute and relative risk by indication for all evaluated AEDs.
| Indication | Placebo Patients With Events per 1,000 Patients | Drug Patients With Events per 1,000 Patients | Relative Risk: Incidence of Events in Drug Patients/Incidence in Placebo Patients | Risk Difference: Additional Drug Patients With Events per 1,000 Patients |
| Epilepsy | 1.0 | 3.4 | 3.5 | 2.4 |
| Psychiatric | 5.7 | 8.5 | 1.5 | 2.9 |
| Other | 1.0 | 1.8 | 1.9 | 0.9 |
| Total | 2.4 | 4.3 | 1.8 | 1.9 |
The relative risk for suicidal thoughts or behavior was higher in clinical trials for epilepsy than in clinical trials for psychiatric or other conditions, but the absolute risk differences were similar for the epilepsy and psychiatric indications.
Anyone considering prescribing LAMICTAL XR or any other AED must balance the risk of suicidal thoughts or behavior with the risk of untreated illness. Epilepsy and many other illnesses for which AEDs are prescribed are themselves associated with morbidity and mortality and an increased risk of suicidal thoughts and behavior. Should suicidal thoughts and behavior emerge during treatment, the prescriber needs to consider whether the emergence of these symptoms in any given patient may be related to the illness being treated.
Patients, their caregivers, and families should be informed that AEDs increase the risk of suicidal thoughts and behavior and should be advised of the need to be alert for the emergence or worsening of the signs and symptoms of depression; any unusual changes in mood or behavior; or the emergence of suicidal thoughts, behavior, or thoughts about self-harm. Behaviors of concern should be reported immediately to healthcare providers.
Aseptic Meningitis
Therapy with lamotrigine increases the risk of developing aseptic meningitis. Because of the potential for serious outcomes of untreated meningitis due to other causes, patients should also be evaluated for other causes of meningitis and treated as appropriate.
Postmarketing cases of aseptic meningitis have been reported in pediatric and adult patients taking lamotrigine for various indications. Symptoms upon presentation have included headache, fever, nausea, vomiting, and nuchal rigidity. Rash, photophobia, myalgia, chills, altered consciousness, and somnolence were also noted in some cases. Symptoms have been reported to occur within 1 day to one and a half months following the initiation of treatment. In most cases, symptoms were reported to resolve after discontinuation of lamotrigine. Re-exposure resulted in a rapid return of symptoms (from within 30 minutes to 1 day following re-initiation of treatment) that were frequently more severe. Some of the patients treated with LAMICTAL who developed aseptic meningitis had underlying diagnoses of systemic lupus erythematosus or other autoimmune diseases.
Cerebrospinal fluid (CSF) analyzed at the time of clinical presentation in reported cases was characterized by a mild to moderate pleocytosis, normal glucose levels, and mild to moderate increase in protein. CSF white blood cell count differentials showed a predominance of neutrophils in a majority of the cases, although a predominance of lymphocytes was reported in approximately one third of the cases. Some patients also had new onset of signs and symptoms of involvement of other organs (predominantly hepatic and renal involvement), which may suggest that in these cases the aseptic meningitis observed was part of a hypersensitivity reaction [see Warnings and Precautions (5.2)].
Potential Medication Errors
Medication errors involving LAMICTAL have occurred. In particular, the names LAMICTAL or lamotrigine can be confused with the names of other commonly used medications. Medication errors may also occur between the different formulations of LAMICTAL. To reduce the potential of medication errors, write and say LAMICTAL XR clearly. Depictions of the LAMICTAL XR Extended-Release Tablets can be found in the Medication Guide. Each LAMICTAL XR tablet has a distinct color and white center, and is printed with “LAMICTAL XR” and the tablet strength. These distinctive features serve to identify the different presentations of the drug and thus may help reduce the risk of medication errors. LAMICTAL XR is supplied in round, unit-of-use bottles with orange caps containing 30 tablets. The label on the bottle includes a depiction of the tablets that further communicates to patients and pharmacists that the medication is LAMICTAL XR and the specific tablet strength included in the bottle. The unit-of-use bottle with a distinctive orange cap and distinctive bottle label features serves to identify the different presentations of the drug and thus may help to reduce the risk of medication errors. To avoid the medication error of using the wrong drug or formulation, patients should be strongly advised to visually inspect their tablets to verify that they are LAMICTAL XR each time they fill their prescription.
Concomitant Use With Oral Contraceptives
Some estrogen-containing oral contraceptives have been shown to decrease serum concentrations of lamotrigine [see Clinical Pharmacology (12.3)]. Dosage adjustments will be necessary in most patients who start or stop estrogen-containing oral contraceptives while taking Lamictal XR[see Dosage and Administration (2.1)]. During the week of inactive hormone preparation (pill-free week) of oral contraceptive therapy, plasma lamotrigine levels are expected to rise, as much as doubling at the end of the week. Adverse reactions consistent with elevated levels of lamotrigine, such as dizziness, ataxia, and diplopia, could occur.
Withdrawal Seizures
As with other AEDs, LAMICTAL XR should not be abruptly discontinued. In patients with epilepsy there is a possibility of increasing seizure frequency. Unless safety concerns require a more rapid withdrawal, the dose of LAMICTAL XR should be tapered over a period of at least 2 weeks (approximately 50% reduction per week) [see Dosage and Administration (2.1)].
Status Epilepticus
Valid estimates of the incidence of treatment-emergent status epilepticus among patients treated with immediate-release lamotrigine are difficult to obtain because reporters participating in clinical trials did not all employ identical rules for identifying cases. At a minimum, 7 of 2,343 adult patients had episodes that could unequivocally be described as status epilepticus. In addition, a number of reports of variably defined episodes of seizure exacerbation (e.g., seizure clusters, seizure flurries) were made.
Sudden Unexplained Death in Epilepsy
During the premarketing development of immediate-release lamotrigine, 20 sudden and unexplained deaths were recorded among a cohort of 4,700 patients with epilepsy (5,747 patient-years of exposure).
Some of these could represent seizure-related deaths in which the seizure was not observed, e.g., at night. This represents an incidence of 0.0035 deaths per patient-year. Although this rate exceeds that expected in a healthy population matched for age and sex, it is within the range of estimates for the incidence of sudden unexplained death in patients with epilepsy not receiving lamotrigine (ranging from 0.0005 for the general population of patients with epilepsy, to 0.004 for a recently studied clinical trial population similar to that in the clinical development program for immediate-release lamotrigine, to 0.005 for patients with refractory epilepsy). Consequently, whether these figures are reassuring or suggest concern depends on the comparability of the populations reported upon to the cohort receiving immediate-release lamotrigine and the accuracy of the estimates provided. Probably most reassuring is the similarity of estimated sudden unexplained death in epilepsy (SUDEP) rates in patients receiving immediate-release lamotrigine and those receiving other AEDs, chemically unrelated to each other, that underwent clinical testing in similar populations. Importantly, that drug is chemically unrelated to lamotrigine. This evidence suggests, although it certainly does not prove, that the high SUDEP rates reflect population rates, not a drug effect.
Addition of Lamictal XR to a Multidrug Regimen That Includes Valproate
Because valproate reduces the clearance of lamotrigine, the dosage of lamotrigine in the presence of valproate is less than half of that required in its absence [see Dosage and Administration (2.1, 2.2), Drug Interactions (7)].
Binding in the Eye and Other Melanin-Containing Tissues
Because lamotrigine binds to melanin, it could accumulate in melanin-rich tissues over time. This raises the possibility that lamotrigine may cause toxicity in these tissues after extended use. Although ophthalmological testing was performed in one controlled clinical trial, the testing was inadequate to exclude subtle effects or injury occurring after long-term exposure. Moreover, the capacity of available tests to detect potentially adverse consequences, if any, of lamotrigine binding to melanin is unknown [see Clinical Pharmacology (12.2)].
Accordingly, although there are no specific recommendations for periodic ophthalmological monitoring, prescribers should be aware of the possibility of long-term ophthalmologic effects.
Laboratory Tests
Plasma Concentrations of Lamotrigine: The value of monitoring plasma concentrations of lamotrigine in patients treated with Lamictal XR has not been established. Because of the possible pharmacokinetic interactions between lamotrigine and other drugs, including AEDs (see Table 6), monitoring of the plasma levels of lamotrigine and concomitant drugs may be indicated, particularly during dosage adjustments. In general, clinical judgment should be exercised regarding monitoring of plasma levels of lamotrigine and other drugs and whether or not dosage adjustments are necessary.
Effect on Leukocytes: Treatment with Lamictal XR caused an increased incidence of subnormal (below the reference range) values in some hematology analytes (e.g., total white blood cells, monocytes). The treatment effect (Lamictal XR % - Placebo %) incidence of subnormal counts was 3% for total white blood cells and 4% for monocytes.
Adverse Reactions
The following adverse reactions are described in more detail in the Warnings and Precautions section of the label:
- Serious skin rashes [see Warnings and Precautions (5.1)]
- Multiorgan hypersensitivity reactions and organ failure [see Warnings and Precautions (5.2)]
- Blood dyscrasias [see Warnings and Precautions (5.3)]
- Suicidal behavior and ideation [see Warnings and Precautions (5.4)]
- Aseptic meningitis [see Warnings and Precautions (5.5)]
- Withdrawal seizures [see Warnings and Precautions (5.8)]
- Status epilepticus [see Warnings and Precautions (5.9)]
- Sudden unexplained death in epilepsy [see Warnings and Precautions (5.10)]
Clinical Trial Experience With Lamictal XR for Treatment of Primary Generalized Tonic-Clonic and Partial Onset Seizures
Most Common Adverse Reactions in Clinical Studies:Adjunctive Therapy in Patients With Epilepsy: Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared with rates in the clinical trials of another drug and may not reflect the rates observed in practice.
Lamictal XR has been evaluated for safety in patients ≥13 years of age with PGTC and partial onset seizures. The most commonly observed adverse reactions in these 2 double-blind, placebo-controlled trials of adjunctive therapy with LAMICTAL XR were, in order of decreasing incidence (treatment difference between LAMICTAL XR and placebo ≥4%): dizziness, tremor/intention tremor, vomiting, and diplopia.
In these 2 trials, adverse reactions led to withdrawal of 4 (2%) patients in the group receiving placebo and 10 (5%) patients in the group receiving Lamictal XR. Dizziness was the most common reason for withdrawal in the group receiving Lamictal XR (5 patients [3%]). The next most common adverse reactions leading to withdrawal in 2 patients each (1%) were rash, headache, nausea, and nystagmus.
Table 4 displays the incidence of adverse reactions in these two 19-week, double-blind, placebo-controlled studies of patients with PGTC and partial onset seizures.
| Body System/Adverse Reaction | Lamictal XR (n = 190) % | Placebo (n = 195) % |
| Ear and labyrinth disorders | ||
| Vertigo | 3 | <1 |
| Eye disorders | ||
| Diplopia | 5 | <1 |
| Vision blurred | 3 | 2 |
| Gastrointestinal disorders | ||
| Nausea |
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