DRUG INTERACTIONS
7 Significant drug interactions with lamotrigine are summarized in Table 13.
Additional details of these drug interaction studies are provided in the Clinical Pharmacology section [see Clinical Pharmacology (12.3)] .
Table 13.
Established and Other Potentially Significant Drug Interactions Concomitant Drug Effect on Concentration of Lamotrigine or Concomitant Drug Clinical Comment Estrogen-containing oral contraceptive preparations containing 30 mcg ethinylestradiol and 150 mcg levonorgestrel ↓ lamotrigine Decreased lamotrigine levels approximately 50%.
↓ levonorgestrel Decrease in levonorgestrel component by 19%.
Carbamazepine (CBZ) and CBZ epoxide ↓ lamotrigine Addition of carbamazepine decreases lamotrigine concentration approximately 40%.
? CBZ epoxide May increase CBZ epoxide levels Phenobarbital/Primidone ↓ lamotrigine Decreased lamotrigine concentration approximately 40%.
Phenytoin (PHT) ↓ lamotrigine Decreased lamotrigine concentration approximately 40%.
Rifampin ↓ lamotrigine Decreased lamotrigine AUC approximately 40%.
Valproate ↑ lamotrigine Increased lamotrigine concentrations slightly more than 2-fold.
? valproate Decreased valproate concentrations an average of 25% over a 3-week period then stabilized in healthy volunteers; no change in controlled clinical trials in epilepsy patients.
↓= Decreased (induces lamotrigine glucuronidation).
↑= Increased (inhibits lamotrigine glucuronidation).
? = Conflicting data.
Valproate increases lamotrigine concentrations more than 2-fold.
(7, 12.3) Carbamazepine, phenytoin, phenobarbital, and primidone decrease lamotrigine concentrations by approximately 40%.
(7, 12.3) Oral estrogen-containing contraceptives and rifampin also decrease lamotrigine concentrations by approximately 50%.
(7, 12.3)
OVERDOSAGE
10 10.1 Human Overdose Experience Overdoses involving quantities up to 15 g have been reported for LAMICTAL, some of which have been fatal.
Overdose has resulted in ataxia, nystagmus, increased seizures, decreased level of consciousness, coma, and intraventricular conduction delay.
10.2 Management of Overdose There are no specific antidotes for lamotrigine.
Following a suspected overdose, hospitalization of the patient is advised.
General supportive care is indicated, including frequent monitoring of vital signs and close observation of the patient.
If indicated, emesis should be induced; usual precautions should be taken to protect the airway.
It should be kept in mind that lamotrigine is rapidly absorbed [see Clinical Pharmacology (12.3)] .
It is uncertain whether hemodialysis is an effective means of removing lamotrigine from the blood.
In 6 renal failure patients, about 20% of the amount of lamotrigine in the body was removed by hemodialysis during a 4-hour session.
A Poison Control Center should be contacted for information on the management of overdosage of LAMICTAL.
DESCRIPTION
11 LAMICTAL (lamotrigine), an AED of the phenyltriazine class, is chemically unrelated to existing AEDs.
Its chemical name is 3,5-diamino-6-(2,3-dichlorophenyl)- as -triazine, its molecular formula is C 9 H 7 N 5 Cl 2 , and its molecular weight is 256.09.
Lamotrigine is a white to pale cream-colored powder and has a pK a of 5.7.
Lamotrigine is very slightly soluble in water (0.17 mg/mL at 25°C) and slightly soluble in 0.1 M HCl (4.1 mg/mL at 25°C).
The structural formula is: LAMICTAL Tablets are supplied for oral administration as 25 mg (white), 100 mg (peach), 150 mg (cream), and 200 mg (blue) tablets.
Each tablet contains the labeled amount of lamotrigine and the following inactive ingredients: lactose; magnesium stearate; microcrystalline cellulose; povidone; sodium starch glycolate; FD&C Yellow No.
6 Lake (100-mg tablet only); ferric oxide, yellow (150-mg tablet only); and FD&C Blue No.
2 Lake (200-mg tablet only).
LAMICTAL Chewable Dispersible Tablets are supplied for oral administration.
The tablets contain 2 mg (white), 5 mg (white), or 25 mg (white) of lamotrigine and the following inactive ingredients: blackcurrant flavor, calcium carbonate, low-substituted hydroxypropylcellulose, magnesium aluminum silicate, magnesium stearate, povidone, saccharin sodium, and sodium starch glycolate.
LAMICTAL ODT Orally Disintegrating Tablets are supplied for oral administration.
The tablets contain 25 mg (white to off-white), 50 mg (white to off-white), 100 mg (white to off-white), or 200 mg (white to off-white) of lamotrigine and the following inactive ingredients: artificial cherry flavor, crospovidone, ethylcellulose, magnesium stearate, mannitol, polyethylene, and sucralose.
LAMICTAL ODT Orally Disintegrating Tablets are formulated using technologies (Microcaps ® and AdvaTab ® ) designed to mask the bitter taste of lamotrigine and achieve a rapid dissolution profile.
Tablet characteristics including flavor, mouth-feel, after-taste, and ease of use were rated as favorable in a study of 108 healthy volunteers.
lamotrigine chemical structure
CLINICAL STUDIES
14 14.1 Epilepsy Monotherapy With LAMICTAL in Adults With Partial Seizures Already Receiving Treatment With Carbamazepine, Phenytoin, Phenobarbital, or Primidone as the Single Antiepileptic Drug: The effectiveness of monotherapy with LAMICTAL was established in a multicenter, double-blind clinical trial enrolling 156 adult outpatients with partial seizures.
The patients experienced at least 4 simple partial, complex partial, and/or secondarily generalized seizures during each of 2 consecutive 4-week periods while receiving carbamazepine or phenytoin monotherapy during baseline.
LAMICTAL (target dose of 500 mg/day) or valproate (1,000 mg/day) was added to either carbamazepine or phenytoin monotherapy over a 4-week period.
Patients were then converted to monotherapy with LAMICTAL or valproate during the next 4 weeks, then continued on monotherapy for an additional 12-week period.
Study endpoints were completion of all weeks of study treatment or meeting an escape criterion.
Criteria for escape relative to baseline were: (1) doubling of average monthly seizure count, (2) doubling of highest consecutive 2-day seizure frequency, (3) emergence of a new seizure type (defined as a seizure that did not occur during the 8-week baseline) that is more severe than seizure types that occur during study treatment, or (4) clinically significant prolongation of generalized tonic-clonic seizures.
The primary efficacy variable was the proportion of patients in each treatment group who met escape criteria.
The percentages of patients who met escape criteria were 42% (32/76) in the group receiving LAMICTAL and 69% (55/80) in the valproate group.
The difference in the percentage of patients meeting escape criteria was statistically significant ( P = 0.0012) in favor of LAMICTAL.
No differences in efficacy based on age, sex, or race were detected.
Patients in the control group were intentionally treated with a relatively low dose of valproate; as such, the sole objective of this study was to demonstrate the effectiveness and safety of monotherapy with LAMICTAL, and cannot be interpreted to imply the superiority of LAMICTAL to an adequate dose of valproate.
Adjunctive Therapy With LAMICTAL in Adults With Partial Seizures: The effectiveness of LAMICTAL as adjunctive therapy (added to other AEDs) was established in 3 multicenter, placebo-controlled, double-blind clinical trials in 355 adults with refractory partial seizures.
The patients had a history of at least 4 partial seizures per month in spite of receiving one or more AEDs at therapeutic concentrations and, in 2 of the studies, were observed on their established AED regimen during baselines that varied between 8 to 12 weeks.
In the third, patients were not observed in a prospective baseline.
In patients continuing to have at least 4 seizures per month during the baseline, LAMICTAL or placebo was then added to the existing therapy.
In all 3 studies, change from baseline in seizure frequency was the primary measure of effectiveness.
The results given below are for all partial seizures in the intent-to-treat population (all patients who received at least one dose of treatment) in each study, unless otherwise indicated.
The median seizure frequency at baseline was 3 per week while the mean at baseline was 6.6 per week for all patients enrolled in efficacy studies.
One study (n = 216) was a double-blind, placebo-controlled, parallel trial consisting of a 24-week treatment period.
Patients could not be on more than 2 other anticonvulsants and valproate was not allowed.
Patients were randomized to receive placebo, a target dose of 300 mg/day of LAMICTAL, or a target dose of 500 mg/day of LAMICTAL.
The median reductions in the frequency of all partial seizures relative to baseline were 8% in patients receiving placebo, 20% in patients receiving 300 mg/day of LAMICTAL, and 36% in patients receiving 500 mg/day of LAMICTAL.
The seizure frequency reduction was statistically significant in the 500-mg/day group compared with the placebo group, but not in the 300-mg/day group.
A second study (n = 98) was a double-blind, placebo-controlled, randomized, crossover trial consisting of two 14-week treatment periods (the last 2 weeks of which consisted of dose tapering) separated by a 4-week washout period.
Patients could not be on more than 2 other anticonvulsants and valproate was not allowed.
The target dose of LAMICTAL was 400 mg/day.
When the first 12 weeks of the treatment periods were analyzed, the median change in seizure frequency was a 25% reduction on LAMICTAL compared with placebo (P <0.001).
The third study (n = 41) was a double-blind, placebo-controlled, crossover trial consisting of two 12-week treatment periods separated by a 4-week washout period.
Patients could not be on more than 2 other anticonvulsants.
Thirteen patients were on concomitant valproate; these patients received 150 mg/day of LAMICTAL.
The 28 other patients had a target dose of 300 mg/day of LAMICTAL.
The median change in seizure frequency was a 26% reduction on LAMICTAL compared with placebo ( P <0.01).
No differences in efficacy based on age, sex, or race, as measured by change in seizure frequency, were detected.
Adjunctive Therapy With LAMICTAL in Pediatric Patients With Partial Seizures: The effectiveness of LAMICTAL as adjunctive therapy in pediatric patients with partial seizures was established in a multicenter, double-blind, placebo-controlled trial in 199 patients 2 to 16 years of age (n = 98 on LAMICTAL, n = 101 on placebo).
Following an 8-week baseline phase, patients were randomized to 18 weeks of treatment with LAMICTAL or placebo added to their current AED regimen of up to 2 drugs.
Patients were dosed based on body weight and valproate use.
Target doses were designed to approximate 5 mg/kg/day for patients taking valproate (maximum dose: 250 mg/day) and 15 mg/kg/day for the patients not taking valproate (maximum dose: 750 mg/day).
The primary efficacy endpoint was percentage change from baseline in all partial seizures.
For the intent-to-treat population, the median reduction of all partial seizures was 36% in patients treated with LAMICTAL and 7% on placebo, a difference that was statistically significant ( P <0.01).
Adjunctive Therapy With LAMICTAL in Pediatric and Adult Patients With Lennox-Gastaut Syndrome: The effectiveness of LAMICTAL as adjunctive therapy in patients with Lennox-Gastaut syndrome was established in a multicenter, double-blind, placebo-controlled trial in 169 patients 3 to 25 years of age (n = 79 on LAMICTAL, n = 90 on placebo).
Following a 4-week single-blind, placebo phase, patients were randomized to 16 weeks of treatment with LAMICTAL or placebo added to their current AED regimen of up to 3 drugs.
Patients were dosed on a fixed-dose regimen based on body weight and valproate use.
Target doses were designed to approximate 5 mg/kg/day for patients taking valproate (maximum dose: 200 mg/day) and 15 mg/kg/day for patients not taking valproate (maximum dose: 400 mg/day).
The primary efficacy endpoint was percentage change from baseline in major motor seizures (atonic, tonic, major myoclonic, and tonic-clonic seizures).
For the intent-to-treat population, the median reduction of major motor seizures was 32% in patients treated with LAMICTAL and 9% on placebo, a difference that was statistically significant ( P <0.05).
Drop attacks were significantly reduced by LAMICTAL (34%) compared with placebo (9%), as were tonic-clonic seizures (36% reduction versus 10% increase for LAMICTAL and placebo, respectively).
Adjunctive Therapy With LAMICTAL in Pediatric and Adult Patients With Primary Generalized Tonic-Clonic Seizures: The effectiveness of LAMICTAL as adjunctive therapy in patients with primary generalized tonic-clonic seizures was established in a multicenter, double-blind, placebo-controlled trial in 117 pediatric and adult patients ≥2 years (n = 58 on LAMICTAL, n = 59 on placebo).
Patients with at least 3 primary generalized tonic-clonic seizures during an 8-week baseline phase were randomized to 19 to 24 weeks of treatment with LAMICTAL or placebo added to their current AED regimen of up to 2 drugs.
Patients were dosed on a fixed-dose regimen, with target doses ranging from 3 mg/kg/day to 12 mg/kg/day for pediatric patients and from 200 mg/day to 400 mg/day for adult patients based on concomitant AED.
The primary efficacy endpoint was percentage change from baseline in primary generalized tonic-clonic seizures.
For the intent-to-treat population, the median percent reduction of primary generalized tonic-clonic seizures was 66% in patients treated with LAMICTAL and 34% on placebo, a difference that was statistically significant ( P = 0.006).
14.2 Bipolar Disorder The effectiveness of LAMICTAL in the maintenance treatment of Bipolar I Disorder was established in 2 multicenter, double-blind, placebo-controlled studies in adult patients who met DSM-IV criteria for Bipolar I Disorder.
Study 1 enrolled patients with a current or recent (within 60 days) depressive episode as defined by DSM-IV and Study 2 included patients with a current or recent (within 60 days) episode of mania or hypomania as defined by DSM-IV.
Both studies included a cohort of patients (30% of 404 patients in Study 1 and 28% of 171 patients in Study 2) with rapid cycling Bipolar Disorder (4 to 6 episodes per year).
In both studies, patients were titrated to a target dose of 200 mg of LAMICTAL, as add-on therapy or as monotherapy, with gradual withdrawal of any psychotropic medications during an 8- to 16-week open-label period.
Overall 81% of 1,305 patients participating in the open-label period were receiving 1 or more other psychotropic medications, including benzodiazepines, selective serotonin reuptake inhibitors (SSRIs), atypical antipsychotics (including olanzapine), valproate, or lithium, during titration of LAMICTAL.
Patients with a CGI-severity score of 3 or less maintained for at least 4 continuous weeks, including at least the final week on monotherapy with LAMICTAL, were randomized to a placebo-controlled, double-blind treatment period for up to 18 months.
The primary endpoint was TIME (time to intervention for a mood episode or one that was emerging, time to discontinuation for either an adverse event that was judged to be related to Bipolar Disorder, or for lack of efficacy).
The mood episode could be depression, mania, hypomania, or a mixed episode.
In Study 1, patients received double-blind monotherapy with LAMICTAL 50 mg/day (n = 50), LAMICTAL 200 mg/day (n = 124), LAMICTAL 400 mg/day (n = 47), or placebo (n = 121).
LAMICTAL (200- and 400-mg/day treatment groups combined) was superior to placebo in delaying the time to occurrence of a mood episode.
Separate analyses of the 200- and 400-mg/day dose groups revealed no added benefit from the higher dose.
In Study 2, patients received double-blind monotherapy with LAMICTAL (100 to 400 mg/day, n = 59), or placebo (n = 70).
LAMICTAL was superior to placebo in delaying time to occurrence of a mood episode.
The mean dose of LAMICTAL was about 211 mg/day.
Although these studies were not designed to separately evaluate time to the occurrence of depression or mania, a combined analysis for the 2 studies revealed a statistically significant benefit for LAMICTAL over placebo in delaying the time to occurrence of both depression and mania, although the finding was more robust for depression.
HOW SUPPLIED
16 /STORAGE AND HANDLING LAMICTAL (lamotrigine) Tablets 25 mg, white, scored, shield-shaped tablets debossed with “LAMICTAL” and “25”, bottles of 100 (NDC 0173-0633-02).
Store at 25°C (77°F); excursions permitted to 15-30°C (59-86°F) [see USP Controlled Room Temperature] in a dry place.
100 mg, peach, scored, shield-shaped tablets debossed with “LAMICTAL” and “100”, bottles of 100 (NDC 0173-0642-55).
150 mg, cream, scored, shield-shaped tablets debossed with “LAMICTAL” and “150”, bottles of 60 (NDC 0173-0643-60).
200 mg, blue, scored, shield-shaped tablets debossed with “LAMICTAL” and “200”, bottles of 60 (NDC 0173-0644-60).
Store at 25°C (77°F); excursions permitted to 15-30°C (59-86°F) [see USP Controlled Room Temperature] in a dry place and protect from light.
LAMICTAL (lamotrigine) Starter Kit for Patients Taking Valproate (Blue Kit) 25 mg, white, scored, shield-shaped tablets debossed with “LAMICTAL” and “25”, blisterpack of 35 tablets (NDC 0173-0633-10).
Store at 25°C (77°F); excursions permitted to 15-30°C (59-86°F) [see USP Controlled Room Temperature] in a dry place.
LAMICTAL (lamotrigine) Starter Kit for Patients Taking Carbamazepine, Phenytoin, Phenobarbital, or Primidone and Not Taking Valproate (Green Kit) 25 mg, white, scored, shield-shaped tablets debossed with “LAMICTAL” and “25” and 100 mg, peach, scored, shield-shaped tablets debossed with “LAMICTAL” and “100”, blisterpack of 98 tablets (84/25-mg tablets and 14/100-mg tablets) (NDC 0173-0817-28).
Store at 25°C (77°F); excursions permitted to 15-30°C (59-86°F) [see USP Controlled Room Temperature] in a dry place and protect from light.
LAMICTAL (lamotrigine) Starter Kit for Patients Not Taking Carbamazepine, Phenytoin, Phenobarbital, Primidone, or Valproate (Orange Kit) 25 mg, white, scored, shield-shaped tablets debossed with “LAMICTAL” and “25” and 100 mg, peach, scored, shield-shaped tablets debossed with “LAMICTAL” and “100”, blisterpack of 49 tablets (42/25-mg tablets and 7/100-mg tablets) (NDC 0173-0594-02).
Store at 25°C (77°F); excursions permitted to 15-30°C (59-86°F) [see USP Controlled Room Temperature] in a dry place and protect from light.
LAMICTAL (lamotrigine) Chewable Dispersible Tablets 2 mg, white to off-white, round tablets debossed with “LTG” over “2”, bottles of 30 (NDC 0173-0699-00).
ORDER DIRECTLY FROM GlaxoSmithKline 1-800-334-4153.
5 mg, white to off-white, caplet-shaped tablets debossed with “GX CL2”, bottles of 100 (NDC 0173-0526-00).
25 mg, white, super elliptical-shaped tablets debossed with “GX CL5”, bottles of 100 (NDC 0173-0527-00).
Store at 25°C (77°F); excursions permitted to 15-30°C (59-86°F) [see USP Controlled Room Temperature] in a dry place.
LAMICTAL ODT (lamotrigine) Orally Disintegrating Tablets 25 mg, white to off-white, round, flat-faced, radius edge, tablets debossed with “LMT” on one side and “25” on the other, Maintenance Packs of 30 (NDC 0173-0772-02).
50 mg, white to off-white, round, flat-faced, radius edge, tablets debossed with “LMT” on one side and “50” on the other, Maintenance Packs of 30 (NDC 0173-0774-02).
100 mg, white to off-white, round, flat-faced, radius edge, tablets debossed with “LAMICTAL” on one side and “100” on the other, Maintenance Packs of 30 (NDC 0173-0776-02).
200 mg, white to off-white, round, flat-faced, radius edge, tablets debossed with “LAMICTAL” on one side and “200” on the other, Maintenance Packs of 30 (NDC 0173-0777-02).
Store between 20°C to 25°C (68°F to 77°F); with excursions permitted between 15°C and 30°C (59°F and 86°F).
LAMICTAL ODT (lamotrigine) Patient Titration Kit for Patients Taking Valproate (Blue ODT Kit) 25 mg, white to off-white, round, flat-faced, radius edge, tablets debossed with “LMT” on one side and “25” on the other, and 50 mg, white to off-white, round, flat-faced, radius edge, tablets debossed with “LMT” on one side and “50” on the other, blisterpack of 28 tablets (21/25-mg tablets and 7/50-mg tablets) (NDC 0173-0779-00).
LAMICTAL ODT (lamotrigine) Patient Titration Kit for Patients Taking Carbamazepine, Phenytoin, Phenobarbital, or Primidone and Not Taking Valproate (Green ODT Kit) 50 mg, white to off-white, round, flat-faced, radius edge, tablets debossed with “LMT” on one side and “50” on the other, and 100 mg, white to off-white, round, flat-faced, radius edge, tablets debossed with “LAMICTAL” on one side and “100” on the other, blisterpack of 56 tablets (42/50-mg tablets and 14/100-mg tablets) (NDC 0173-0780-00).
LAMICTAL ODT (lamotrigine) Patient Titration Kit for Patients Not Taking Carbamazepine, Phenytoin, Phenobarbital, Primidone, or Valproate (Orange ODT Kit) 25 mg, white to off-white, round, flat-faced, radius edge, tablets debossed with “LMT” on one side and “25” on the other, 50 mg, white to off-white, round, flat-faced, radius edge, tablets debossed with “LMT” on one side and “50” on the other, and 100 mg, white to off-white, round, flat-faced, radius edge, tablets debossed with “LAMICTAL” on one side and “100” on the other, blisterpack of 35 (14/25-mg tablets, 14/50-mg tablets, and 7/100-mg tablets) (NDC 0173-0778-00).
Store between 20°C to 25°C (68°F to 77°F); with excursions permitted between 15°C and 30°C (59°F and 86°F).
Blisterpacks: If the product is dispensed in a blisterpack, the patient should be advised to examine the blisterpack before use and not use if blisters are torn, broken, or missing.
RECENT MAJOR CHANGES
Warnings and Precautions, Multiorgan Hypersensitivity Reactions and Organ Failure (5.2) August 2011
GERIATRIC USE
8.5 Geriatric Use Clinical studies of LAMICTAL for epilepsy and in Bipolar Disorder did not include sufficient numbers of subjects 65 years of age and over to determine whether they respond differently from younger subjects or exhibit a different safety profile than that of younger patients.
In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy.
DOSAGE FORMS AND STRENGTHS
3 Tablets: 25 mg, 100 mg, 150 mg, and 200 mg scored.
(3.1, 16) Chewable Dispersible Tablets: 2 mg, 5 mg, and 25 mg.
(3.2, 16) Orally Disintegrating Tablets : 25 mg, 50 mg, 100 mg, and 200 mg.
(3.3, 16) 3.1 Tablets 25 mg, white, scored, shield-shaped tablets debossed with “LAMICTAL” and “25.” 100 mg, peach, scored, shield-shaped tablets debossed with “LAMICTAL” and “100.” 150 mg, cream, scored, shield-shaped tablets debossed with “LAMICTAL” and “150.” 200 mg, blue, scored, shield-shaped tablets debossed with “LAMICTAL” and “200.” 3.2 Chewable Dispersible Tablets 2 mg, white to off-white, round tablets debossed with “LTG” over “2.” 5 mg, white to off-white, caplet-shaped tablets debossed with “GX CL2.” 25 mg, white, super elliptical-shaped tablets debossed with “GX CL5.” 3.3 Orally Disintegrating Tablets 25 mg, white to off-white, round, flat-faced, radius edge, tablets debossed with “LMT” on one side and “25” on the other side.
50 mg, white to off-white, round, flat-faced, radius edge, tablets debossed with “LMT” on one side and “50” on the other side.
100 mg, white to off-white, round, flat-faced, radius edge, tablets debossed with “LAMICTAL” on one side and “100” on the other side.
200 mg, white to off-white, round, flat-faced, radius edge, tablets debossed with “LAMICTAL” on one side and “200” on the other side.
3.4 Potential Medication Errors Patients should be strongly advised to visually inspect their tablets to verify that they are receiving LAMICTAL as well as the correct formulation of LAMICTAL each time they fill their prescription.
Depictions of the LAMICTAL Tablets, Chewable Dispersible Tablets, and Orally Disintegrating Tablets can be found in the Medication Guide that accompanies the product.
MECHANISM OF ACTION
12.1 Mechanism of Action The precise mechanism(s) by which lamotrigine exerts its anticonvulsant action are unknown.
In animal models designed to detect anticonvulsant activity, lamotrigine was effective in preventing seizure spread in the maximum electroshock (MES) and pentylenetetrazol (scMet) tests, and prevented seizures in the visually and electrically evoked after-discharge (EEAD) tests for antiepileptic activity.
Lamotrigine also displayed inhibitory properties in the kindling model in rats both during kindling development and in the fully kindled state.
The relevance of these models to human epilepsy, however, is not known.
One proposed mechanism of action of lamotrigine, the relevance of which remains to be established in humans, involves an effect on sodium channels.
In vitro pharmacological studies suggest that lamotrigine inhibits voltage-sensitive sodium channels, thereby stabilizing neuronal membranes and consequently modulating presynaptic transmitter release of excitatory amino acids (e.g., glutamate and aspartate).
Although the relevance for human use is unknown, the following data characterize the performance of lamotrigine in receptor binding assays.
Lamotrigine had a weak inhibitory effect on the serotonin 5-HT 3 receptor (IC 50 = 18 µM).
It does not exhibit high affinity binding (IC 50 >100 µM) to the following neurotransmitter receptors: adenosine A 1 and A 2 ; adrenergic α 1 , α 2 , and β; dopamine D 1 and D 2 ; γ-aminobutyric acid (GABA) A and B; histamine H 1 ; kappa opioid; muscarinic acetylcholine; and serotonin 5-HT 2 .
Studies have failed to detect an effect of lamotrigine on dihydropyridine-sensitive calcium channels.
It had weak effects at sigma opioid receptors (IC 50 = 145 µM).
Lamotrigine did not inhibit the uptake of norepinephrine, dopamine, or serotonin (IC 50 >200 µM) when tested in rat synaptosomes and/or human platelets in vitro.
Effect of Lamotrigine on N-Methyl d-Aspartate-Receptor Mediated Activity: Lamotrigine did not inhibit N-methyl d-aspartate (NMDA)-induced depolarizations in rat cortical slices or NMDA-induced cyclic GMP formation in immature rat cerebellum, nor did lamotrigine displace compounds that are either competitive or noncompetitive ligands at this glutamate receptor complex (CNQX, CGS, TCHP).
The IC 50 for lamotrigine effects on NMDA-induced currents (in the presence of 3 µM of glycine) in cultured hippocampal neurons exceeded 100 µM.
The mechanisms by which lamotrigine exerts its therapeutic action in Bipolar Disorder have not been established.
INDICATIONS AND USAGE
1 LAMICTAL is an antiepileptic drug (AED) indicated for: Epilepsy—adjunctive therapy in patients ≥2 years of age: (1.1) partial seizures.
primary generalized tonic-clonic seizures.
generalized seizures of Lennox-Gastaut syndrome.
Epilepsy—monotherapy in patients ≥16 years of age: conversion to monotherapy in patients with partial seizures who are receiving treatment with carbamazepine, phenobarbital, phenytoin, primidone, or valproate as the single AED.
(1.1) Bipolar Disorder in patients ≥18 years of age: maintenance treatment of Bipolar I Disorder to delay the time to occurrence of mood episodes in patients treated for acute mood episodes with standard therapy.
(1.2) 1.1 Epilepsy Adjunctive Therapy: LAMICTAL is indicated as adjunctive therapy for the following seizure types in patients ≥2 years of age: partial seizures primary generalized tonic-clonic seizures generalized seizures of Lennox-Gastaut syndrome Monotherapy: LAMICTAL is indicated for conversion to monotherapy in adults (≥16 years of age) with partial seizures who are receiving treatment with carbamazepine, phenytoin, phenobarbital, primidone, or valproate as the single antiepileptic drug (AED).
Safety and effectiveness of LAMICTAL have not been established (1) as initial monotherapy; (2) for conversion to monotherapy from AEDs other than carbamazepine, phenytoin, phenobarbital, primidone, or valproate; or (3) for simultaneous conversion to monotherapy from 2 or more concomitant AEDs.
1.2 Bipolar Disorder LAMICTAL is indicated for the maintenance treatment of Bipolar I Disorder to delay the time to occurrence of mood episodes (depression, mania, hypomania, mixed episodes) in adults (≥18 years of age) treated for acute mood episodes with standard therapy.
The effectiveness of LAMICTAL in the acute treatment of mood episodes has not been established.
The effectiveness of LAMICTAL as maintenance treatment was established in 2 placebo-controlled trials in patients with Bipolar I Disorder as defined by DSM-IV [see Clinical Studies (14.2)] .
The physician who elects to prescribe LAMICTAL for periods extending beyond 16 weeks should periodically re-evaluate the long-term usefulness of the drug for the individual patient.
PEDIATRIC USE
8.4 Pediatric Use LAMICTAL is indicated for adjunctive therapy in patients ≥2 years of age for partial seizures, the generalized seizures of Lennox-Gastaut syndrome, and primary generalized tonic-clonic seizures.
Safety and efficacy of LAMICTAL, used as adjunctive treatment for partial seizures, were not demonstrated in a small randomized, double-blind, placebo-controlled, withdrawal study in very young pediatric patients (1 to 24 months of age).
LAMICTAL was associated with an increased risk for infectious adverse reactions (LAMICTAL 37%, placebo 5%), and respiratory adverse reactions (LAMICTAL 26%, placebo 5%).
Infectious adverse reactions included bronchiolitis, bronchitis, ear infection, eye infection, otitis externa, pharyngitis, urinary tract infection, and viral infection.
Respiratory adverse reactions included nasal congestion, cough, and apnea.
Safety and effectiveness in patients below the age of 18 years with Bipolar Disorder have not been established.
PREGNANCY
8.1 Pregnancy Teratogenic Effects: Pregnancy Category C.
No evidence of teratogenicity was found in mice, rats, or rabbits when lamotrigine was orally administered to pregnant animals during the period of organogenesis at doses up to 1.2, 0.5, and 1.1 times, respectively, on a mg/m 2 basis, the highest usual human maintenance dose (i.e., 500 mg/day).
However, maternal toxicity and secondary fetal toxicity producing reduced fetal weight and/or delayed ossification were seen in mice and rats, but not in rabbits at these doses.
Teratology studies were also conducted using bolus intravenous administration of the isethionate salt of lamotrigine in rats and rabbits.
In rat dams administered an intravenous dose at 0.6 times the highest usual human maintenance dose, the incidence of intrauterine death without signs of teratogenicity was increased.
A behavioral teratology study was conducted in rats dosed during the period of organogenesis.
At day 21 postpartum, offspring of dams receiving 5 mg/kg/day or higher displayed a significantly longer latent period for open field exploration and a lower frequency of rearing.
In a swimming maze test performed on days 39 to 44 postpartum, time to completion was increased in offspring of dams receiving 25 mg/kg/day.
These doses represent 0.1 and 0.5 times the clinical dose on a mg/m 2 basis, respectively.
Lamotrigine did not affect fertility, teratogenesis, or postnatal development when rats were dosed prior to and during mating, and throughout gestation and lactation at doses equivalent to 0.4 times the highest usual human maintenance dose on a mg/m 2 basis.
When pregnant rats were orally dosed at 0.1, 0.14, or 0.3 times the highest human maintenance dose (on a mg/m 2 basis) during the latter part of gestation (days 15 to 20), maternal toxicity and fetal death were seen.
In dams, food consumption and weight gain were reduced, and the gestation period was slightly prolonged (22.6 vs.
22.0 days in the control group).
Stillborn pups were found in all 3 drug-treated groups with the highest number in the high-dose group.
Postnatal death was also seen, but only in the 2 highest doses, and occurred between days 1 and 20.
Some of these deaths appear to be drug-related and not secondary to the maternal toxicity.
A no-observed-effect level (NOEL) could not be determined for this study.
Although lamotrigine was not found to be teratogenic in the above studies, lamotrigine decreases fetal folate concentrations in rats, an effect known to be associated with teratogenesis in animals and humans.
There are no adequate and well-controlled studies in pregnant women.
Because animal reproduction studies are not always predictive of human response, this drug should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.
Non-Teratogenic Effects: As with other AEDs, physiological changes during pregnancy may affect lamotrigine concentrations and/or therapeutic effect.
There have been reports of decreased lamotrigine concentrations during pregnancy and restoration of pre-partum concentrations after delivery.
Dosage adjustments may be necessary to maintain clinical response.
Pregnancy Exposure Registry: To provide information regarding the effects of in utero exposure to LAMICTAL, physicians are advised to recommend that pregnant patients taking LAMICTAL enroll in the North American Antiepileptic Drug (NAAED) Pregnancy Registry.
This can be done by calling the toll-free number 1-888-233-2334, and must be done by patients themselves.
Information on the registry can also be found at the website http://www.aedpregnancyregistry.org/.
Physicians are also encouraged to register patients in the Lamotrigine Pregnancy Registry; enrollment in this registry must be done prior to any prenatal diagnostic tests and before fetal outcome is known .
Physicians can obtain information by calling the Lamotrigine Pregnancy Registry at 1-800-336-2176 (toll-free).
NUSRING MOTHERS
8.3 Nursing Mothers Lamotrigine is present in milk from lactating women taking LAMICTAL.
Data from multiple small studies indicate that lamotrigine plasma levels in human milk-fed infants have been reported to be as high as 50% of the maternal serum levels.
Neonates and young infants are at risk for high serum levels because maternal serum and milk levels can rise to high levels postpartum if lamotrigine dosage has been increased during pregnancy but not later reduced to the pre-pregnancy dosage.
Lamotrigine exposure is further increased due to the immaturity of the infant glucuronidation capacity needed for drug clearance.
Events including apnea, drowsiness, and poor sucking have been reported in infants who have been human milk-fed by mothers using lamotrigine; whether or not these events were caused by lamotrigine is unknown.
Human milk-fed infants should be closely monitored for adverse events resulting from lamotrigine.
Measurement of infant serum levels should be performed to rule out toxicity if concerns arise.
Human milk-feeding should be discontinued in infants with lamotrigine toxicity.
Caution should be exercised when LAMICTAL is administered to a nursing woman.
BOXED WARNING
WARNING: SERIOUS SKIN RASHES LAMICTAL ® 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 (2 to 16 years of age) receiving LAMICTAL as adjunctive therapy for epilepsy and 0.3% (3 per 1,000) in adults on adjunctive therapy for epilepsy.
In clinical trials of bipolar and other mood disorders, the rate of serious rash was 0.08% (0.8 per 1,000) in adult patients receiving LAMICTAL as initial monotherapy and 0.13% (1.3 per 1,000) in adult patients receiving LAMICTAL as adjunctive therapy.
In a prospectively followed cohort of 1,983 pediatric patients (2 to 16 years of age) with epilepsy taking adjunctive LAMICTAL, there was 1 rash-related death.
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.
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.
There are suggestions, yet to be proven, that the risk of rash may also be increased by (1) coadministration of LAMICTAL with valproate (includes valproic acid and divalproex sodium), (2) exceeding the recommended initial dose of LAMICTAL, or (3) exceeding the recommended dose escalation for LAMICTAL.
However, cases have occurred in the absence of these factors.
Nearly all cases of life-threatening rashes caused by LAMICTAL 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, it is not possible to predict reliably which rashes will prove to be serious or life threatening.
Accordingly, LAMICTAL 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)] .
WARNING: SERIOUS SKIN RASHES See full prescribing information for complete boxed warning.
Cases of life-threatening serious rashes, including Stevens-Johnson syndrome, toxic epidermal necrolysis, and/or rash-related death, have been caused by LAMICTAL.
The rate of serious rash is greater in pediatric patients than in adults.
Additional factors that may increase the risk of rash include (5.1): coadministration with valproate exceeding recommended initial dose of LAMICTAL exceeding recommended dose escalation of LAMICTAL Benign rashes are also caused by LAMICTAL; however, it is not possible to predict which rashes will prove to be serious or life threatening.
LAMICTAL should be discontinued at the first sign of rash, unless the rash is clearly not drug related.
(5.1)
WARNING AND CAUTIONS
5 WARNINGS AND PRECAUTIONS Life-threatening serious rash and/or rash-related death may result.
(Boxed Warning, 5.1) Fatal or life-threatening hypersensitivity reaction: Multiorgan hypersensitivity reactions, also known as Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS), may be fatal or life threatening.
Early signs may include rash, fever, and lymphadenopathy.
These reactions may be associated with other organ involvement, such as hepatitis, hepatic failure, blood dyscrasias, or acute multiorgan failure.
LAMICTAL should be discontinued if alternate etiology for this reaction is not found.
(5.2) Blood dyscrasias (e.g., neutropenia, thrombocytopenia, pancytopenia): May occur, either with or without an associated hypersensitivity syndrome.
(5.3) Suicidal behavior and ideation.
(5.4) Clinical worsening, emergence of new symptoms, and suicidal ideation/behaviors may be associated with treatment of bipolar disorder.
Patients should be closely monitored, particularly early in treatment or during dosage changes.
(5.5) Aseptic meningitis reported in pediatric and adult patients.
(5.6) Medication errors involving LAMICTAL have occurred.
In particular the names LAMICTAL or lamotrigine can be confused with names of other commonly used medications.
Medication errors may also occur between the different formulations of LAMICTAL.
(3.4, 5.7, 16, 17.10) 5.1 Serious Skin Rashes [see Boxed Warning] Pediatric Population: The incidence of serious rash associated with hospitalization and discontinuation of LAMICTAL in a prospectively followed cohort of pediatric patients (2 to 16 years of age) with epilepsy receiving adjunctive therapy 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.
Adult Population: Serious rash associated with hospitalization and discontinuation of LAMICTAL occurred in 0.3% (11 of 3,348) of adult patients who received LAMICTAL in premarketing clinical trials of epilepsy.
In the bipolar and other mood disorders clinical trials, the rate of serious rash was 0.08% (1 of 1,233) of adult patients who received LAMICTAL as initial monotherapy and 0.13% (2 of 1,538) of adult patients who received LAMICTAL as adjunctive therapy.
No fatalities occurred among these individuals.
However, 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 LAMICTAL 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 LAMICTAL 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 of LAMICTAL 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 should be discontinued if an alternative etiology for the signs or symptoms cannot be established.
Prior to initiation of treatment with LAMICTAL, 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.
5.3 Blood Dyscrasias There have been reports of blood dyscrasias 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.
5.4 Suicidal Behavior and Ideation Antiepileptic drugs (AEDs), including LAMICTAL, 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 (mono- 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 7 shows absolute and relative risk by indication for all evaluated AEDs.
Table 7.
Risk by Indication for Antiepileptic Drugs in the Pooled Analysis 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 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.
5.5 Use in Patients With Bipolar Disorder Acute Treatment of Mood Episodes: Safety and effectiveness of LAMICTAL in the acute treatment of mood episodes have not been established.
Children and Adolescents (less than 18 years of age): Safety and effectiveness of LAMICTAL in patients below the age of 18 years with mood disorders have not been established [see Suicidal Behavior and Ideation (5.4)] .
Clinical Worsening and Suicide Risk Associated With Bipolar Disorder: Patients with bipolar disorder may experience worsening of their depressive symptoms and/or the emergence of suicidal ideation and behaviors (suicidality) whether or not they are taking medications for bipolar disorder.
Patients should be closely monitored for clinical worsening (including development of new symptoms) and suicidality, especially at the beginning of a course of treatment or at the time of dose changes.
In addition, patients with a history of suicidal behavior or thoughts, those patients exhibiting a significant degree of suicidal ideation prior to commencement of treatment, and young adults are at an increased risk of suicidal thoughts or suicide attempts, and should receive careful monitoring during treatment [see Suicidal Behavior and Ideation (5.5)] .
Consideration should be given to changing the therapeutic regimen, including possibly discontinuing the medication, in patients who experience clinical worsening (including development of new symptoms) and/or the emergence of suicidal ideation/behavior especially if these symptoms are severe, abrupt in onset, or were not part of the patient’s presenting symptoms.
Prescriptions for LAMICTAL should be written for the smallest quantity of tablets consistent with good patient management in order to reduce the risk of overdose.
Overdoses have been reported for LAMICTAL, some of which have been fatal [see Overdosage (10.1)] .
5.6 Aseptic Meningitis Therapy with LAMICTAL 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 LAMICTAL 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 LAMICTAL.
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)] .
5.7 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 clearly.
Depictions of the LAMICTAL Tablets, Chewable Dispersible Tablets, and Orally Disintegrating Tablets can be found in the Medication Guide that accompanies the product to highlight the distinctive markings, colors, and shapes that serve to identify the different presentations of the drug and thus may help 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, as well as the correct formulation of LAMICTAL, each time they fill their prescription.
5.8 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 [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.
5.9 Withdrawal Seizures As with other AEDs, LAMICTAL should not be abruptly discontinued.
In patients with epilepsy there is a possibility of increasing seizure frequency.
In clinical trials in patients with Bipolar Disorder, 2 patients experienced seizures shortly after abrupt withdrawal of LAMICTAL; however, there were confounding factors that may have contributed to the occurrence of seizures in these bipolar patients.
Unless safety concerns require a more rapid withdrawal, the dose of LAMICTAL should be tapered over a period of at least 2 weeks (approximately 50% reduction per week) [see Dosage and Administration (2.1)] .
5.10 Status Epilepticus Valid estimates of the incidence of treatment-emergent status epilepticus among patients treated with LAMICTAL 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.
5.11 Sudden Unexplained Death in Epilepsy (SUDEP) During the premarketing development of LAMICTAL, 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 deaths in patients with epilepsy not receiving LAMICTAL (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 LAMICTAL, 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 LAMICTAL and the accuracy of the estimates provided.
Probably most reassuring is the similarity of estimated SUDEP rates in patients receiving LAMICTAL and those receiving other AEDs, chemically unrelated to each other, that underwent clinical testing in similar populations.
Importantly, that drug is chemically unrelated to LAMICTAL.
This evidence suggests, although it certainly does not prove, that the high SUDEP rates reflect population rates, not a drug effect.
5.12 Addition of LAMICTAL 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.
5.13 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’s 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.
5.14 Laboratory Tests The value of monitoring plasma concentrations of lamotrigine in patients treated with LAMICTAL has not been established.
Because of the possible pharmacokinetic interactions between lamotrigine and other drugs including AEDs (see Table 15), 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.
INFORMATION FOR PATIENTS
17 PATIENT COUNSELING INFORMATION See FDA-approved patient labeling (Medication Guide).
17.1 Rash Prior to initiation of treatment with LAMICTAL, 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.
17.2 Multiorgan Hypersensitivity Reactions, Blood Dyscrasias, and Organ Failure Patients should be instructed that multiorgan hypersensitivity reactions and acute multiorgan failure may occur with LAMICTAL.
Isolated organ failure or isolated blood dyscrasias without evidence of multiorgan hypersensitivity may also occur.
Patients should contact their physician immediately if they experience any signs or symptoms of these conditions [see Warnings and Precautions (5.2, 5.3)] .
17.3 Suicidal Thinking and Behavior Patients, their caregivers, and families should be counseled that AEDs, including LAMICTAL, may increase the risk of suicidal thoughts and behavior and should be advised of the need to be alert for the emergence or worsening of 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.
17.4 Worsening of Seizures Patients should be advised to notify their physician if worsening of seizure control occurs.
17.5 Central Nervous System Adverse Effects Patients should be advised that LAMICTAL may cause dizziness, somnolence, and other symptoms and signs of CNS depression.
Accordingly, they should be advised neither to drive a car nor to operate other complex machinery until they have gained sufficient experience on LAMICTAL to gauge whether or not it adversely affects their mental and/or motor performance.
17.6 Pregnancy and Nursing Patients should be advised to notify their physicians if they become pregnant or intend to become pregnant during therapy.
Patients should be advised to notify their physicians if they intend to breastfeed or are breastfeeding an infant.
Patients should also be encouraged to enroll in the NAAED Pregnancy Registry if they become pregnant.
This registry is collecting information about the safety of antiepileptic drugs during pregnancy.
To enroll, patients can call the toll-free number 1-888-233-2334 [see Use in Specific Populations (8.1)] .
Patients who intend to breastfeed should be informed that LAMICTAL is present in breast milk and that they should monitor their child for potential adverse effects of this drug.
Benefits and risks of continuing breastfeeding should be discussed with the patient.
17.7 Oral Contraceptive Use Women should be advised to notify their physician if they plan to start or stop use of oral contraceptives or other female hormonal preparations.
Starting estrogen-containing oral contraceptives may significantly decrease lamotrigine plasma levels and stopping estrogen-containing oral contraceptives (including the “pill-free” week) may significantly increase lamotrigine plasma levels [see Warnings and Precautions (5.8), Clinical Pharmacology (12.3)] .
Women should also be advised to promptly notify their physician if they experience adverse reactions or changes in menstrual pattern (e.g., break-through bleeding) while receiving LAMICTAL in combination with these medications.
17.8 Discontinuing LAMICTAL Patients should be advised to notify their physician if they stop taking LAMICTAL for any reason and not to resume LAMICTAL without consulting their physician.
17.9 Aseptic Meningitis Patients should be advised that LAMICTAL may cause aseptic meningitis.
Patients should be advised to notify their physician immediately if they develop signs and symptoms of meningitis such as headache, fever, nausea, vomiting, stiff neck, rash, abnormal sensitivity to light, myalgia, chills, confusion, or drowsiness while taking LAMICTAL.
17.10 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 clearly.
Depictions of the LAMICTAL Tablets, Chewable Dispersible Tablets, and Orally Disintegrating Tablets can be found in the Medication Guide that accompanies the product to highlight the distinctive markings, colors, and shapes that serve to identify the different presentations of the drug and thus may help reduce the risk of medication errors.
To avoid a 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, as well as the correct formulation of LAMICTAL, each time they fill their prescription [see Dosage Forms and Strengths (3.1, 3.2, 3.3), How Supplied/Storage and Handling (16)] .
LAMICTAL is a registered trademark of GlaxoSmithKline.
Microcaps and AdvaTab are registered trademarks of Eurand, Inc.
GlaxoSmithKline Research Triangle Park, NC 27709 LAMICTAL Tablets and Chewable Dispersible Tablets are manufactured by DSM Pharmaceuticals, Inc., Greenville, NC 27834 or GlaxoSmithKline, Research Triangle Park, NC 27709 LAMICTAL Orally Disintegrating Tablets are manufactured by Eurand, Inc., Vandalia, OH 45377 ©2011, GlaxoSmithKline.
All rights reserved.
November 2011 LMT:7PI
DOSAGE AND ADMINISTRATION
2 Dosing is based on concomitant medications, indication, and patient age.
(2.2, 2.4) To avoid an increased risk of rash, the recommended initial dose and subsequent dose escalations should not be exceeded.
LAMICTAL Starter Kits and LAMICTAL ODT Patient Titration Kits are available for the first 5 weeks of treatment.
(2.1, 16) Do not restart LAMICTAL in patients who discontinued due to rash unless the potential benefits clearly outweigh the risks.
(2.1) Adjustments to maintenance doses will in most cases be required in patients starting or stopping estrogen-containing oral contraceptives.
(2.1, 5.8) LAMICTAL should be discontinued over a period of at least 2 weeks (approximately 50% reduction per week).
(2.1, 5.9) Epilepsy Adjunctive therapy—See Table 1 for patients >12 years of age and Tables 2 and 3 for patients 2 to 12 years.
(2.2) Conversion to monotherapy—See Table 4.
(2.3) Bipolar Disorder: See Tables 5 and 6.
(2.4) 2.1 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 with valproate, (2) exceeding the recommended initial dose of LAMICTAL, or (3) exceeding the recommended dose escalation for LAMICTAL.
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 of LAMICTAL is exceeded and in patients with a history of allergy or rash to other AEDs.
LAMICTAL Starter Kits and LAMICTAL ® ODT ™ Patient Titration Kits provide LAMICTAL at doses consistent with the recommended titration schedule for the first 5 weeks of treatment, based upon concomitant medications for patients with epilepsy (>12 years of age) and Bipolar I Disorder (≥18 years of age) and are intended to help reduce the potential for rash.
The use of LAMICTAL Starter Kits and LAMICTAL ODT Patient Titration Kits is recommended for appropriate patients who are starting or restarting LAMICTAL [see How Supplied/Storage and Handling (16)] .
It is recommended that LAMICTAL 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 lamotrigine, 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 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 may require adjustment based on clinical response.
Target Plasma Levels for Patients With Epilepsy or Bipolar Disorder: A therapeutic plasma concentration range has not been established for lamotrigine.
Dosing of LAMICTAL should be based on therapeutic response [see Clinical Pharmacology (12.3)] .
Women Taking Estrogen-Containing Oral Contraceptives: Starting LAMICTAL 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 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 based on the concomitant AED or other concomitant medications (see Table 1 or Table 5).
See below for adjustments to maintenance doses of LAMICTAL in women taking estrogen-containing oral contraceptives.
Adjustments to the Maintenance Dose of LAMICTAL 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 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 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 or Table 5) 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 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 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 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 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 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 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 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 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 should be based on patients’ concomitant medications (see Tables 1-3 or Table 5); 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 LAMICTAL.
Because there is inadequate experience in this population, LAMICTAL should be used with caution in these patients.
Discontinuation Strategy: Epilepsy: For patients receiving LAMICTAL in combination with other AEDs, a reevaluation 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, 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 (5.9)] .
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.
Bipolar Disorder: In the controlled clinical trials, there was no increase in the incidence, type, or severity of adverse reactions following abrupt termination of LAMICTAL.
In clinical trials in patients with Bipolar Disorder, 2 patients experienced seizures shortly after abrupt withdrawal of LAMICTAL.
However, there were confounding factors that may have contributed to the occurrence of seizures in these bipolar patients.
Discontinuation of LAMICTAL should involve a step-wise reduction of dose over at least 2 weeks (approximately 50% per week) unless safety concerns require a more rapid withdrawal [see Warnings and Precautions (5.9)] .
2.2 Epilepsy – Adjunctive Therapy This section provides specific dosing recommendations for patients greater than 12 years of age and patients 2 to 12 years of age.
Within each of these age-groups, specific dosing recommendations are provided depending upon concomitant AED or other concomitant medications (Table 1 for patients greater than 12 years of age and Table 2 for patients 2 to 12 years of age).
A weight-based dosing guide for patients 2 to 12 years of age on concomitant valproate is provided in Table 3.
Patients Over 12 Years of Age: Recommended dosing guidelines are summarized in Table 1.
Table 1.
Escalation Regimen for LAMICTAL in Patients Over 12 Years of Age With Epilepsy For Patients TAKING Valproate a For Patients NOT TAKING Carbamazepine, Phenytoin, Phenobarbital, Primidone, b or Valproate a For Patients TAKING Carbamazepine, Phenytoin, Phenobarbital, or Primidone b and NOT TAKING Valproate a Weeks 1 and 2 25 mg every other day 25 mg every day 50 mg/day Weeks 3 and 4 25 mg every day 50 mg/day 100 mg/day (in 2 divided doses) Week 5 onwards to maintenance Increase by 25 to 50 mg/day every 1 to 2 weeks Increase by 50 mg/day every 1 to 2 weeks Increase by 100 mg/day every 1 to 2 weeks.
Usual maintenance dose 100 to 200 mg/day with valproate alone 100 to 400 mg/day with valproate and other drugs that induce glucuronidation (in 1 or 2 divided doses) 225 to 375 mg/day (in 2 divided doses) 300 to 500 mg/day (in 2 divided doses) a Valproate has been shown to inhibit glucuronidation and decrease the apparent clearance of lamotrigine [see Drug Interactions (7), Clinical Pharmacology (12.3)] .
b These 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.
Patients 2 to 12 Years of Age: Recommended dosing guidelines are summarized in Table 2.
Smaller starting doses and slower dose escalations than those used in clinical trials are recommended because of the suggestion that the risk of rash may be decreased by smaller starting doses and slower dose escalations.
Therefore, maintenance doses will take longer to reach in clinical practice than in clinical trials.
It may take several weeks to months to achieve an individualized maintenance dose.
Maintenance doses in patients weighing less than 30 kg, regardless of age or concomitant AED, may need to be increased as much as 50%, based on clinical response.
The smallest available strength of LAMICTAL Chewable Dispersible Tablets is 2 mg, and only whole tablets should be administered.
If the calculated dose cannot be achieved using whole tablets, the dose should be rounded down to the nearest whole tablet [see How Supplied/Storage and Handling (16) and Medication Guide] .
Table 2.
Escalation Regimen for LAMICTAL in Patients 2 to 12 Years of Age With Epilepsy For Patients TAKING Valproate a For Patients NOT TAKING Carbamazepine, Phenytoin, Phenobarbital, Primidone, b or Valproate a For Patients TAKING Carbamazepine, Phenytoin, Phenobarbital, or Primidone b and NOT TAKING Valproate a Weeks 1 and 2 0.15 mg/kg/day in 1 or 2 divided doses, rounded down to the nearest whole tablet (see Table 3 for weight-based dosing guide) 0.3 mg/kg/day in 1 or 2 divided doses, rounded down to the nearest whole tablet 0.6 mg/kg/day in 2 divided doses, rounded down to the nearest whole tablet Weeks 3 and 4 0.3 mg/kg/day in 1 or 2 divided doses, rounded down to the nearest whole tablet (see Table 3 for weight-based dosing guide) 0.6 mg/kg/day in 2 divided doses, rounded down to the nearest whole tablet 1.2 mg/kg/day in 2 divided doses, rounded down to the nearest whole tablet Week 5 onwards to maintenance The dose should be increased every 1 to 2 weeks as follows: calculate 0.3 mg/kg/day, round this amount down to the nearest whole tablet, and add this amount to the previously administered daily dose The dose should be increased every 1 to 2 weeks as follows: calculate 0.6 mg/kg/day, round this amount down to the nearest whole tablet, and add this amount to the previously administered daily dose The dose should be increased every 1 to 2 weeks as follows: calculate 1.2 mg/kg/day, round this amount down to the nearest whole tablet, and add this amount to the previously administered daily dose Usual maintenance dose 1 to 5 mg/kg/day (maximum 200 mg/day in 1 or 2 divided doses) 1 to 3 mg/kg/day with valproate alone 4.5 to 7.5 mg/kg/day (maximum 300 mg/day in 2 divided doses) 5 to 15 mg/kg/day (maximum 400 mg/day in 2 divided doses) Maintenance dose in patients less than 30 kg May need to be increased by as much as 50%, based on clinical response May need to be increased by as much as 50%, based on clinical response May need to be increased by as much as 50%, based on clinical response Note: Only whole tablets should be used for dosing.
a Valproate has been shown to inhibit glucuronidation and decrease the apparent clearance of lamotrigine [see Drug Interactions (7), Clinical Pharmacology (12.3)] .
b These 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.
Table 3.
The Initial Weight-Based Dosing Guide for Patients 2 to 12 Years of Age Taking Valproate (Weeks 1 to 4) With Epilepsy If the patient’s weight is Give this daily dose, using the most appropriate combination of LAMICTAL 2-mg and 5-mg tablets Greater than And less than Weeks 1 and 2 Weeks 3 and 4 6.7 kg 14 kg 2 mg every other day 2 mg every day 14.1 kg 27 kg 2 mg every day 4 mg every day 27.1 kg 34 kg 4 mg every day 8 mg every day 34.1 kg 40 kg 5 mg every day 10 mg every day Usual Adjunctive Maintenance Dose for Epilepsy: The usual maintenance doses identified in Tables 1 and 2 are derived from dosing regimens employed in the placebo-controlled adjunctive studies in which the efficacy of LAMICTAL was established.
In patients receiving multidrug regimens employing carbamazepine, phenytoin, phenobarbital, or primidone without valproate , maintenance doses of adjunctive LAMICTAL as high as 700 mg/day have been used.
In patients receiving valproate alone , maintenance doses of adjunctive LAMICTAL as high as 200 mg/day have been used.
The advantage of using doses above those recommended in Tables 1 through 4 has not been established in controlled trials.
2.3 Epilepsy – Conversion From Adjunctive Therapy to Monotherapy The goal of the transition regimen is to effect the conversion to monotherapy with LAMICTAL under conditions that ensure adequate seizure control while mitigating the risk of serious rash associated with the rapid titration of LAMICTAL.
The recommended maintenance dose of LAMICTAL as monotherapy is 500 mg/day given in 2 divided doses.
To avoid an increased risk of rash, the recommended initial dose and subsequent dose escalations of LAMICTAL should not be exceeded [see Boxed Warning] .
Conversion From Adjunctive Therapy With Carbamazepine, Phenytoin, Phenobarbital, or Primidone to Monotherapy With LAMICTAL: After achieving a dose of 500 mg/day of LAMICTAL according to the guidelines in Table 1, the concomitant AED should be withdrawn by 20% decrements each week over a 4-week period.
The regimen for the withdrawal of the concomitant AED is based on experience gained in the controlled monotherapy clinical trial.
Conversion From Adjunctive Therapy With Valproate to Monotherapy With LAMICTAL: The conversion regimen involves 4 steps outlined in Table 4.
Table 4.
Conversion From Adjunctive Therapy With Valproate to Monotherapy With LAMICTAL in Patients ≥16 Years of Age With Epilepsy LAMICTAL Valproate Step 1 Achieve a dose of 200 mg/day according to guidelines in Table 1 (if not already on 200 mg/day).
Maintain previous stable dose.
Step 2 Maintain at 200 mg/day.
Decrease to 500 mg/day by decrements no greater than 500 mg/day/week and then maintain the dose of 500 mg/day for 1 week.
Step 3 Increase to 300 mg/day and maintain for 1 week.
Simultaneously decrease to 250 mg/day and maintain for 1 week.
Step 4 Increase by 100 mg/day every week to achieve maintenance dose of 500 mg/day.
Discontinue.
Conversion From Adjunctive Therapy With Antiepileptic Drugs Other Than Carbamazepine, Phenytoin, Phenobarbital, Primidone, or Valproate to Monotherapy With LAMICTAL: No specific dosing guidelines can be provided for conversion to monotherapy with LAMICTAL with AEDs other than carbamazepine, phenobarbital, phenytoin, primidone, or valproate.
2.4 Bipolar Disorder The goal of maintenance treatment with LAMICTAL is to delay the time to occurrence of mood episodes (depression, mania, hypomania, mixed episodes) in patients treated for acute mood episodes with standard therapy.
The target dose of LAMICTAL is 200 mg/day (100 mg/day in patients taking valproate, which decreases the apparent clearance of lamotrigine, and 400 mg/day in patients not taking valproate and taking either carbamazepine, phenytoin, phenobarbital, primidone, or other drugs such as rifampin that increase the apparent clearance of lamotrigine).
In the clinical trials, doses up to 400 mg/day as monotherapy were evaluated; however, no additional benefit was seen at 400 mg/day compared with 200 mg/day [see Clinical Studies (14.2)] .
Accordingly, doses above 200 mg/day are not recommended.
Treatment with LAMICTAL is introduced, based on concurrent medications, according to the regimen outlined in Table 5.
If other psychotropic medications are withdrawn following stabilization, the dose of LAMICTAL should be adjusted.
For patients discontinuing valproate, the dose of LAMICTAL should be doubled over a 2-week period in equal weekly increments (see Table 6).
For patients discontinuing carbamazepine, phenytoin, phenobarbital, primidone, or other drugs such as rifampin that induce lamotrigine glucuronidation, the dose of LAMICTAL should remain constant for the first week and then should be decreased by half over a 2-week period in equal weekly decrements (see Table 6).
The dose of LAMICTAL may then be further adjusted to the target dose (200 mg) as clinically indicated.
If other drugs are subsequently introduced, the dose of LAMICTAL may need to be adjusted.
In particular, the introduction of valproate requires reduction in the dose of LAMICTAL [see Drug Interactions (7), Clinical Pharmacology (12.3)] .
To avoid an increased risk of rash, the recommended initial dose and subsequent dose escalations of LAMICTAL should not be exceeded [see Boxed Warning] .
Table 5.
Escalation Regimen for LAMICTAL for Patients With Bipolar Disorder For Patients TAKING Valproate a For Patients NOT TAKING Carbamazepine, Phenytoin, Phenobarbital, Primidone, b or Valproate a For Patients TAKING Carbamazepine, Phenytoin, Phenobarbital, or Primidone b and NOT TAKING Valproate a Weeks 1 and 2 25 mg every other day 25 mg daily 50 mg daily Weeks 3 and 4 25 mg daily 50 mg daily 100 mg daily, in divided doses Week 5 50 mg daily 100 mg daily 200 mg daily, in divided doses Week 6 100 mg daily 200 mg daily 300 mg daily, in divided doses Week 7 100 mg daily 200 mg daily up to 400 mg daily, in divided doses a Valproate has been shown to inhibit glucuronidation and decrease the apparent clearance of lamotrigine [see Drug Interactions (7), Clinical Pharmacology (12.3)] .
b These 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.
Table 6.
Dosage Adjustments to LAMICTAL for Patients With Bipolar Disorder Following Discontinuation of Psychotropic Medications Discontinuation of Psychotropic Drugs (excluding Carbamazepine, Phenytoin, Phenobarbital, Primidone, b or Valproate a ) After Discontinuation of Valproate a After Discontinuation of Carbamazepine, Phenytoin, Phenobarbital, or Primidone b Current dose of LAMICTAL (mg/day) 100 Current dose of LAMICTAL (mg/day) 400 Week 1 Maintain current dose of LAMICTAL 150 400 Week 2 Maintain current dose of LAMICTAL 200 300 Week 3 onward Maintain current dose of LAMICTAL 200 200 a Valproate has been shown to inhibit glucuronidation and decrease the apparent clearance of lamotrigine [see Drug Interactions (7), Clinical Pharmacology (12.3)] .
b These 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.
The benefit of continuing treatment in patients who had been stabilized in an 8- to 16-week open-label phase with LAMICTAL was established in 2 randomized, placebo-controlled clinical maintenance trials [see Clinical Studies (14.2)] .
However, the optimal duration of treatment with LAMICTAL has not been established.
Thus, patients should be periodically reassessed to determine the need for maintenance treatment.
2.5 Administration of LAMICTAL Chewable Dispersible Tablets LAMICTAL Chewable Dispersible Tablets may be swallowed whole, chewed, or dispersed in water or diluted fruit juice.
If the tablets are chewed, consume a small amount of water or diluted fruit juice to aid in swallowing.
To disperse LAMICTAL Chewable Dispersible Tablets, add the tablets to a small amount of liquid (1 teaspoon, or enough to cover the medication).
Approximately 1 minute later, when the tablets are completely dispersed, swirl the solution and consume the entire quantity immediately.
No attempt should be made to administer partial quantities of the dispersed tablets.
2.6 Administration of LAMICTAL ODT Orally Disintegrating Tablets LAMICTAL ODT Orally Disintegrating Tablets should be placed onto the tongue and moved around in the mouth.
The tablet will disintegrate rapidly, can be swallowed with or without water, and can be taken with or without food.