Lamotrigine extended-release as adjunctive therapy with optional conversion to monotherapy in older adults with epilepsy.

PURPOSE: To determine the tolerability and efficacy of lamotrigine extended-release (LTG XR) as adjunctive therapy with optional conversion to monotherapy in patients ages≥65 years with epilepsy. METHODS: This open-label study included the standard LTG XR dose escalation, an 8-week Adjunctive Maintenance Phase (AMP), a 13-week Adjunctive Optimization Phase or Conversion and Monotherapy Phase, and a Taper/Follow-Up Phase. At the end of the AMP, patients on a single concomitant antiepileptic drug (AED) were converted to LTG XR monotherapy over 5 weeks and then remained in the Monotherapy Maintenance Phase for 8 weeks. All other patients remained in the study on concomitant AEDs for an additional 13 weeks in the Adjunctive Optimization Phase. KEY FINDINGS: The number of patients who took ≥1 dose of study medication was 121. Of the 92 patients completing the AMP, 68 patients (74%) were deemed by their treating physician to be eligible to proceed with monotherapy; the remaining 24 patients (26%) continued in the Adjunctive Optimization Phase. The types of adverse events reported with LTG XR were similar to those in studies of LTG XR in younger adult patients with epilepsy and studies of LTG immediate-release (IR) across age groups with epilepsy. No serious rashes were reported. For subjects who were not seizure free at baseline (n=55), the median baseline seizure frequency was 0.5 seizures per week. During the entire treatment period, the median percent change from baseline was 90% (p<0.0001). Fifty-two (52) patients (76%) of the 68 who entered the monotherapy phase successfully converted to monotherapy. SIGNIFICANCE: In this small open label study, LTG-XR was safe and effective when added to the AED regimen of older patients with epilepsy. Many patients were able to be converted to LTG-XR monotherapy.

Long-term tolerability and safety of lamotrigine extended-release: pooled analysis of three clinical trials.

BACKGROUND: In three randomized double-blind clinical trials, lamotrigine extended-release (lamotrigine XR) was demonstrated to be effective in the adjunctive treatment of intractable partial seizures or primary generalized tonic-clonic seizures and as monotherapy for partial seizures. OBJECTIVE: A pooled analysis of the data from these three clinical trials was performed to determine whether the tolerability and safety profile of lamotrigine XR was similar to lamotrigine immediate-release (lamotrigine IR). METHODS: This report describes results of a pooled analysis of the tolerability and safety data from the double-blind and open-label phases of these three trials. The number of patients in the integrated database exposed to one or more doses of lamotrigine XR was 662. RESULTS: Duration of exposure to lamotrigine XR was ≥26 weeks in 82.5 % of patients and ≥52 weeks in 40.8 % of patients [mean (standard deviation) 39.8 (23.3) weeks]. The number of patients with one or more adverse events during double-blind or open-label treatment was 455 (69 %). The most common treatment-emergent adverse events, regardless of suspected cause, were headache (25 % of patients) and dizziness (16 % of patients). The number of patients with one or more adverse events considered to be reasonably attributed to lamotrigine XR during double-blind or open-label treatment was 202 (31 %). The most common adverse events considered to be reasonably attributed to lamotrigine XR were dizziness (10 % of patients) and headache (6 % of patients). Lamotrigine-attributed rash was reported in 4 % of patients and was the reason for premature withdrawal in 2 %. Adverse events leading to premature withdrawal were reported in 7 % of patients. The incidence of serious lamotrigine-attributed adverse events was 1 %. One case of serious rash was reported. No cases of rash were reported to be Stevens-Johnson syndrome or toxic epidermal necrolysis. Two deaths (acute cardiac failure and acute lamotrigine poisoning) were considered reasonably attributable to lamotrigine XR. No evidence of lamotrigine-attributed changes was observed in clinical laboratory data or vital signs. CONCLUSION: The results show that lamotrigine XR is well tolerated with safety and tolerability profiles similar to those of lamotrigine IR. Given the similar safety, tolerability and efficacy profiles of lamotrigine XR and lamotrigine IR, the extended-release formulation may be preferable for many patients because of its ease of use (with once-daily dosing regardless of concomitant antiepileptic drug), the potential for enhanced compliance with once-daily dosing, and the provision of more stable serum drug concentrations. The benefit of once-daily dosing must be balanced with the potentially greater negative impact of a missed dose.

Analysis of three lamotrigine extended-release clinical trials: comparison of pragmatic ITT and LOCF methodologies.

Early withdrawal of patients from a clinical trial can compromise the robustness of the data by introducing bias into the analysis. This is most commonly addressed by using the "intent to treat" (ITT) population and "last observation carried forward" (LOCF) methodology, where a patient's last assessment is carried forward. This can lead to overstatement of treatment efficacy especially if events indicative of treatment failure are infrequent. An alternative methodology, labeled "pragmatic ITT" (P-ITT), requires patients to have a positive outcome and to complete the trial in order to be considered a treatment success by that outcome measure. Data from 3 randomized multicenter lamotrigine extended-release (LTG XR) trials were analyzed and response (proportions seizure-free and with 50% response) were compared using LOCF and P-ITT methodologies. In 2 of the 3 trials, a lower response for both seizure freedom and 50% response was seen during the Maintenance phase using the P-ITT methodology. In the trial that did not show a difference, only a small number of patients withdrew early, thus negating the benefit brought by the P-ITT method. Differences between methodologies were not noted when evaluation was applied to the entire treatment period, most likely a reflection of the fact that a therapeutic dose of lamotrigine is not rapidly achieved. We propose that the P-ITT may be a simpler, more informative method for evaluating the effectiveness of a drug, especially in comparison to another active drug(s).

Effects of lamotrigine and phenytoin on the pharmacokinetics of atorvastatin in healthy volunteers.

PURPOSE: Statins and antiepileptic drugs (AEDs) are frequently coprescribed to individuals with hypercholesterolemia and new-onset seizures. Statins are metabolized by the cytochrome P450 (CYP) enzyme system. Interactions between statins and agents that undergo CYP metabolism are common. In this study, the effects of two commonly prescribed AEDs, lamotrigine and phenytoin, with different routes of metabolism (CYP3A4 versus glucuronic acid conjugation) on atorvastatin pharmacokinetics were evaluated. METHODS: Healthy volunteers (n=119) received atorvastatin 40 mg/day for 7 days followed by addition of lamotrigine (target 300 mg/day) or phenytoin (target ~4 mg/kg per day) in this open-label, single-sequence, two-cohort study. Serial pharmacokinetic sampling of atorvastatin was conducted on day 7 of atorvastatin dosing and day 70 of lamotrigine + atorvastatin dosing or day 28 of phenytoin + atorvastatin dosing. Main outcome measures were steady-state area under the curve over the 24-h dosing interval (AUC((0-τ)) ) and maximum concentration (C(max) ) of atorvastatin and its metabolites, 2OH-atorvastatin and 4OH-atorvastatin, in the presence of lamotrigine or phenytoin. KEY FINDINGS: When atorvastatin was administered with lamotrigine compared with when atorvastatin was administered alone, atorvastatin AUC((0-τ)) was within bounds indicating no interaction, whereas C(max) was slightly higher(14%); AUC((0-τ)) and C(max) were 3% and 20% higher, respectively, for 2OH-atorvastatin and 25% and 21% higher, respectively, for 4OH-atorvastatin.When atorvastatin was administered with phenytoin compared with when atorvastatin was administered alone, reductions in AUC((0-τ)) and C(max) were observed for atorvastatin (54% and 24%, respectively), 2OH-atorvastatin (53% and 22%, respectively), and 4OH-atorvastatin (44% and 52%, respectively). SIGNIFICANCE: Pharmacokinetics of atorvastatin were not significantly affected by coadministration with lamotrigine. Phenytoin significantly reduced atorvastatin bioavailability. Consistent with the published literature, these data are consonant with the possibility that atorvastatin does not require dose adjustment when coadministered with lamotrigine at doses to 300 mg/day, whereas atorvastatin coadministered with phenytoin may require atorvastatin dose adjustment to maintain atorvastatin exposure.

Adjunctive lamotrigine XR for primary generalized tonic-clonic seizures in a randomized, placebo-controlled study.

Efficacy and tolerability of once-daily adjunctive lamotrigine extended-release (XR) for primary generalized tonic-clonic (PGTC) seizures in epilepsy were evaluated. Patients (n = 153) ≥ 13 years old diagnosed with epilepsy with PGTC seizures were randomized to once-daily adjunctive lamotrigine XR or placebo in a double-blind, parallel-group trial comprising a baseline phase, a 7-week double-blind escalation phase, and a 12-week double-blind maintenance phase. Lamotrigine XR was more effective than placebo with respect to median percentage reduction from baseline in weekly PGTC seizure frequency (primary endpoint-19-week treatment phase: 75.4% vs 32.1%, P<0.0001; escalation phase: 61.9% vs 30.6%, P = 0.0016; maintenance phase: 89.7% vs 33.3%, P<0.0001). Lamotrigine XR was more effective than placebo with respect to the percentage of patients with ≥50% reduction in PGTC seizure frequency. Significant separation from placebo for ≥50% reduction in PGTC seizures was observed beginning on treatment day 8. The most common adverse event was headache (lamotrigine XR 14%, placebo 16%).

Effects of lamotrigine compared with levetiracetam on anger, hostility, and total mood in patients with partial epilepsy.

PURPOSE: To assess anger/hostility during treatment with lamotrigine adjunctive therapy versus levetiracetam adjunctive therapy in patients with partial seizures. METHODS: This randomized, double-blind, parallel-group study in adults with partial seizures included an 8-week escalation phase, during which adjunctive lamotrigine (n = 132) or adjunctive levetiracetam (n = 136) was titrated to a target dose, and a 12-week, double-blind maintenance phase, during which dosages of study medication and concomitant antiepileptic drugs were maintained. The primary endpoint was change from baseline to the end of the maintenance phase (week 20) in the Anger-Hostility subscale score of the Profile of Mood States (POMS). RESULTS: Improvement with lamotrigine relative to levetiracetam was observed for mean +/- SD (standard deviation) change from baseline to the end of the maintenance phase (week 20) on the Anger-Hostility subscale (lamotrigine -2.0 +/- 8.2, levetiracetam -0.3 +/- 8.4; p = 0.024) (the primary endpoint); the Anger-Hostility subscale on weeks 5, 6, 7, 8, 9, 11, 12, 14, 16, 18, and 19; and the Total Mood Disturbance score on weeks 6, 7, 8, 9, 11, 12, 17, 19, and 20. Improvement (p < 0.05) with lamotrigine relative to levetiracetam was also observed on the POMS subscales Depression-Dejection, Vigor-Activity, Fatigue-Inertia, and Confusion-Bewilderment. No difference in seizure frequency was observed between groups. The most common adverse events with both medications were headache and dizziness. DISCUSSION: Adjunctive lamotrigine significantly improved Anger-Hostility subscale scores relative to adjunctive levetiracetam in patients with partial seizures at the end of 20 weeks. This difference was consistently observed throughout the treatment period. Similar improvement with lamotrigine versus levetiracetam was observed for other mood symptoms.

Effects of lamotrigine on mood in older adults with epilepsy and co-morbid depressive symptoms: an open-label, multicentre, prospective study.

BACKGROUND: Both epilepsy and depressive symptoms are more prevalent in older individuals than in any other age group. Furthermore, depressive symptoms are among the most common interictal psychiatric co-morbid disorders in people with epilepsy. For these reasons, pharmacological treatment of epilepsy that might also confer antidepressant effects may be particularly beneficial in older patients. In this respect, lamotrigine is of considerable interest amongst antiepileptic drugs (AEDs) because it has proven thymoleptic activity. OBJECTIVE: These analyses, conducted on a data set drawn from a previously reported, open-label, multicentre, prospective study, examined the effect of lamotrigine on mood in adults aged>or=50 years with epilepsy and co-morbid depressive symptoms. All subjects were receiving background AED therapy at baseline. METHODS: Of the 158 subjects enrolled in the initial study, 40 adults (24 women, 16 men) met the age criterion for these analyses. The study consisted of a screening/baseline phase and four treatment phases over 36 weeks: lamotrigine escalation phase (7 weeks); lamotrigine maintenance or adjunctive therapy phase (12 weeks); concomitant AED withdrawal phase (5 weeks); and lamotrigine monotherapy phase (12 weeks). Psychometric evaluation of mood utilized the Beck Depression Inventory (BDI-II), Center for Epidemiological Studies Depression Scale (CES-D), the Neurological Disorders Depression Inventory in Epilepsy (NDDI-E) and the Profile of Mood States (POMS). Scores at the end of the adjunctive and monotherapy phases were compared with baseline scores. Lower scores on these scales indicate less depressive symptomatology. RESULTS: Mean baseline scores for the BDI-II, CES-D, NDDI-E and POMS were 15.8, 24.3, 13.8 and 57.7, respectively. Change scores were statistically significant (p<0.01) compared with baseline at the end of the adjunctive and monotherapy phases for all four psychometric measures of mood, with the exceptions of BDI-II and NDDI-E at the end of the adjunctive phase. CONCLUSIONS: The older adults in these analyses presented with low to moderate levels of depressive symptoms. Addition of lamotrigine to background AED therapy demonstrated antidepressant activity similar to that for the whole sample in the initial study. Given that the onset and prevalence of epilepsy are higher in older adults than in any other age group, pharmacological treatment for epilepsy in older patients that might also confer antidepressant therapy may be particularly beneficial.

Lamotrigine monotherapy for newly diagnosed typical absence seizures in children.

PURPOSE: To evaluate the efficacy, tolerability, and effects on behavior and psychosocial functioning of lamotrigine monotherapy in children with newly diagnosed typical absence seizures. PATIENTS AND METHODS: Children meeting enrollment criteria (n=54) received a confirmatory 24-h ambulatory electroencephalogram (EEG) and then entered a Escalation Phase of up to 20-weeks during which lamotrigine was titrated until seizures were controlled or maximum dose (10.2mg/kg) was reached. Seizure freedom was assessed by diary review and clinic hyperventilation (clinic HV) and then confirmed by EEG with hyperventilation (HV/EEG). Patients who maintained seizure freedom for two consecutive weekly visits were entered into the Maintenance Phase (n=30). Diary, clinic HV, and HV/EEG data were supplemented with 24-h ambulatory EEG at baseline and the ends of the Escalation and Maintenance Phases. Health outcome assessments were completed at screening and at the end of the Maintenance Phase. RESULTS: By the end of the Escalation Phase, seizure-free rates (responders) were 59% by seizure diary (n=51), 56% by HV/EEG (n=54) (primary endpoint), and 49% by 24-h ambulatory EEG (n=49). During the Maintenance Phase, 89% (week 24) and 86% (week 32) remained seizure free by diary (n=28), 78% by clinic HV (n=27), and 81% by 24-h ambulatory EEG (n=26). Seizure freedom was first observed beginning at the fifth week of the Escalation Phase. The most frequent adverse events were headache and cough. Health outcome scores were either improved or unchanged at the end of the Maintenance Phase. CONCLUSIONS: Lamotrigine monotherapy results in complete seizure freedom in a substantial number of children with typical absence seizures. Lamotrigine was well tolerated in this study.

Depressive symptoms in epilepsy: prevalence, impact, aetiology, biological correlates and effect of treatment with antiepileptic drugs.

Occurring in up to 80% of patients with epilepsy, depression in epilepsy may manifest as (i) major depressive disorder, meeting Diagnostic and Statistical Manual, 4th edition (DSM-IV) diagnostic criteria; (ii) atypical depression or dysthymia; or (iii) a dysthymic-like disorder with intermittent symptoms that can be milder than those of major depression. Depressive symptoms impair patients' health-related quality of life and may affect the clinical course of epilepsy. Depressive symptoms in epilepsy have been attributed to several causes, including endocrine and/or metabolic effects of seizures; the psychological response to epilepsy and its associated mental, physical and social challenges; common pathogenic mechanisms between depression and epilepsy; and the adverse effects of certain antiepileptic drugs (AEDs), particularly GABAergic agents, such as vigabatrin, tiagabine, topiramate and phenobarbital. Whereas some AEDs impair mood, others appear to improve aspects of mood or are mood neutral. Demonstrable antidepressant efficacy of AEDs used to manage seizures could have a significant impact on the care of patients with epilepsy. The AED lamotrigine has been demonstrated to be effective in the treatment of depressive symptoms in patients with epilepsy. In randomized, double-blind, clinical trials in patients with epilepsy, depressive symptoms improved more with lamotrigine monotherapy than valproate monotherapy and more with lamotrigine adjunctive therapy than placebo. Results of open-label studies of lamotrigine monotherapy and adjunctive therapy are consistent with the results of double-blind clinical trials. Lamotrigine-associated improvement in depressive symptoms is independent of its anticonvulsant efficacy. In prospective assessments, gabapentin, levetiracetam and oxcarbazepine each exhibited potentially beneficial effects on depressive symptoms in patients with epilepsy. However, evidence for the efficacy of gabapentin, levetiracetam and oxcarbazepine in the treatment of depressive symptoms in epilepsy is inconclusive at present because the effects of each agent have only been reported in single studies of an open-label design and with small sample sizes.

Steady-state pharmacokinetics of lamotrigine when converting from a twice-daily immediate-release to a once-daily extended-release formulation in subjects with epilepsy (The COMPASS Study).

PURPOSE: To compare the pharmacokinetics (PK) of lamotrigine (LTG) when converting from twice-daily immediate-release (LTG-IR) to once-daily extended-release (LTG-XR) in subjects with epilepsy. METHODS: An open-label, conversion study was conducted, consisting of a 2-week LTG-IR Baseline Phase, followed by a 2-week LTG-XR Treatment Phase and a 1-week LTG-IR Phase. Forty-four subjects (> or =13 years of age) were enrolled and grouped as metabolically neutral (15), induced (15), or inhibited (14) based on the effects of the concomitant antiepileptic drugs (AEDs) on the clearance of LTG. The primary outcome was LTG PK parameters upon conversion. Secondary outcomes included seizure frequency, adverse events, and subject's preference. RESULTS: LTG-XR and LTG-IR regimens were similar with respect to area under curve from 0 to 24 h (AUC (0-24)), apart from the induced group, where the AUC (0-24) of LTG-XR was on average 21% lower than for LTG-IR. A reduction in the LTG Cmax was observed for LTG-XR compared to LTG-IR resulting in a decrease in the peak-to-trough fluctuation in serum LTG concentrations. The steady-state, dose-normalized, trough concentrations for LTG-XR were similar to those of LTG-IR. The median time to peak concentration (Tmax) following administration of LTG-XR ranged from 4 to 6 h, 6 to 10 h, and 9 to 11 h in the induced, neutral, and inhibited groups, respectively. In comparison, the median Tmax following administration of LTG-IR was between 1 and 1.5 h. CONCLUSIONS: Trough concentrations of LTG can be maintained on conversion from twice-daily LTG-IR to once-daily LTG-XR at the same total daily dose.

Conversion to lamotrigine monotherapy from valproate monotherapy in older adolescent patients with epilepsy.

BACKGROUND: Pharmacokinetic interactions can make necessary anti-epileptic medication (AED) changes hazardous for children with epilepsy. We report the utility of a dosing algorithm designed to maintain stable trough lamotrigine (LTG) concentrations during conversion from valproate (VPA) to LTG monotherapy in adolescents aged 16-20 years. METHODS: Patients were enrolled into the study if they required a change in their AED regimen due to lack of efficacy or intolerable side effects. Conversion to LTG monotherapy took place in a four part treatment algorithm. Lamotrigine was escalated according to a target dose of 200 mg/day over 8-weeks. Valproate was withdrawn over a period of 2-6 weeks, depending on the initial dose. Lamotrigine dose was further escalated to 500 mg/day and continued for four weeks as mono therapy. Trough serum concentrations of LTG were measured during each phase of the trial. RESULTS: Twelve of 16 patients completed the study. After the LTG escalation to 200 mg/day, mean trough serum concentrations of 8.0 microg/mL did not differ significantly from the 9.5 microg/mL after VPA withdrawal or the 9.2 microg/mL after 4 weeks of monotherapy at 500 mg/day. Adverse events led to premature discontinuation for one subject. Two subjects withdrew due to worsening seizures during LTG monotherapy possibly due to non-compliance. Limitations of the trial include the open label design and small sample size of the sub-analysis. CONCLUSION: In adolescent patients, this algorithm produces stable LTG serum concentrations with favorable tolerability during a transition from VPA to LTG mono therapy.

Lamotrigine in patients with epilepsy and comorbid depressive symptoms.

PURPOSE: This open-label study evaluated the antidepressant qualities of lamotrigine (LTG) in people with epilepsy. METHODS: Eligible patients exhibited low to moderate depressive symptoms and required a change in antiepileptic drug (AED) therapy, but were excluded if they had a major depressive disorder (MDD). Lamotrigine was added onto a stable AED regimen, and self-report instruments were administered to evaluate changes in mood states. Evaluations were conducted at baseline, at the end of 19 weeks of adjunctive treatment, and 36 weeks following conversion to monotherapy. RESULTS: One hundred and fifty-eight patients with epilepsy participated; 96 patients completed adjunctive treatment, and 66 patients completed monotherapy. Intent-to-treat analyses for all instruments showed improvement in depression scores after adjunctive LTG treatment. Improvement was maintained for those converted to monotherapy. CONCLUSIONS: These data suggest that LTG may have antidepressant activity for patients with epilepsy and comorbid low to moderate depressive symptoms, and warrant a randomized controlled trial for validation.

Adjunctive lamotrigine for refractory epilepsy in adolescents with mental retardation.

Epilepsy is a major comorbid condition in adolescents with mental retardation and is often characterized by multiple seizure types that are refractory to treatment. This study (n = 22) describes a subanalysis of data from a larger multicenter study of adjunctive lamotrigine therapy in patients with mental retardation and refractory epilepsy and focuses on the outcome measures of seizure reduction, safety and tolerability, and impact on behaviors in adolescents with mental retardation and refractory epilepsy. The study kept baseline antiepileptic drugs constant and titrated lamotrigine over 8 weeks to the target dose, followed by an 8-week maintenance phase and then a 12-week optimization phase during which all antiepileptic drugs and lamotrigine could be altered as clinically indicated. Sixty percent of subjects had a 50% decrease in seizures by the end of the maintenance phase and a mean 39% reduction in seizure frequency by the end of the maintenance phase (25% by end of study) compared with baseline. Global improvements were observed in most patients, with statistically significant improvements in the Aberrant Behavior Checklist and the Habilitative Improvement Scale, which is predictive of less need for supportive care in activities of daily living and thus enhanced potential for greater independence. Lamotrigine-associated improvements in behavior can be attributed to improved control of seizures, a reduction in concomitant antiepileptic drugs, and/or direct mood-stabilizing and behavior-enhancing properties independent of the antiseizure effects of the drug. The results of this study suggest that lamotrigine is an important treatment option in adolescents with mental retardation and comorbid epilepsy.

Lamotrigine adjunctive therapy among children and adolescents with primary generalized tonic-clonic seizures.

CONTEXT AND OBJECTIVE: Primary generalized tonic-clonic seizures are relatively more common among children than among adults. Primary generalized tonic-clonic seizures are associated with increased risk of injury and death. Therefore, effective control of primary generalized tonic-clonic seizures is necessary to reduce epilepsy-related morbidity and mortality. Lamotrigine has demonstrated efficacy from published randomized clinical trials for childhood partial seizures, absence seizures, and for the generalized seizures associated with Lennox-Gastaut syndrome. A randomized, blinded, placebo-controlled study was conducted to assess the efficacy and tolerability of adjunctive therapy with lamotrigine in the treatment of primary generalized tonic-clonic seizures among patients > or = 2 years of age; we report the data from children and adolescents 2 to 20 years of age from this randomized clinical trial. This is the first published analysis of data from a randomized, double-blind, controlled clinical trial of primary generalized tonic-clonic seizures focusing on children and adolescents. PATIENTS AND METHODS: We randomly assigned (1:1) 117 patients, aged 2 to 55 years, with primary generalized tonic-clonic seizures inadequately controlled on 1 to 2 current antiepileptic drugs and with evidence of primary generalized tonic-clonic seizures on electroencephalogram and no historical or electroencephalogram evidence of partial seizures to either lamotrigine or placebo in a double-blind parallel group clinical trial from 2001 through 2004. We analyzed the subgroup of children and adolescents, aged 2 to 20 years (n = 45), from this randomized clinical trial. Patients having > or = 3 primary generalized tonic-clonic seizures over an 8-week baseline were randomly assigned (1:1) to receive either lamotrigine or placebo. The treatment period consisted of an escalation phase (12 weeks for patients 2-12 years; 7 weeks for patients > 12 years) and a maintenance phase (12 weeks). The study had 4 phases: screening phase, baseline phase, escalation phase, and maintenance phase. During the screening phase, baseline medical examinations and seizure type and seizure frequency assessments were performed. During the 8-week baseline phase, the number and dosages of concomitant antiepileptic drugs were maintained while seizure frequency was assessed. The assessment of primary generalized tonic-clonic seizure frequency was determined during the 8-week baseline phase. Patients eligible for random assignment experienced > or =3 primary generalized tonic-clonic seizures during the baseline phase and > or = 1 primary generalized tonic-clonic seizure in the 8 weeks before the baseline phase. Lamotrigine was introduced and titrated using a schedule based on the patients' age and concurrent antiepileptic drug regimen. During the escalation phase, the number and doses of concomitant antiepileptic drugs were not changed. The escalation phase was followed by a 12-week maintenance phase during which time the lamotrigine dose was maintained at a specific dose defined by the patients' age and concomitant antiepileptic drugs, whereas the doses of concurrent antiepileptic drugs were maintained at a constant dose. Concurrent antiepileptic drugs could not be discontinued or added during the maintenance phase. The primary efficacy end point measure was the median reduction in the frequency of primary generalized tonic-clonic seizures from baseline; seizure counts were recorded prospectively in standardized daily seizure diaries. Other efficacy end point data for analysis were as follows: the median seizure counts, the median percentage change from the baseline phase in average monthly seizure frequency for other generalized seizure types, and the percentage of patients with a reduction of > or = 25%, > or = 50%, > or = 75%, or 100% in frequencies of primary generalized tonic-clonic seizures and all generalized seizures during the escalation phase and/or maintenance phase relative to the baseline phase. Accurate counts of absence seizure frequency require electroencephalogram-video monitoring; absence seizure frequency was not an outcome measure for this analysis. RESULTS: Forty-five (21 lamotrigine and 24 placebo) patients 2 to 19 years of age were randomly assigned and received study drug. Eight patients (3 lamotrigine and 5 placebo) had a combination of clinical (myoclonus and/or absence seizures) and electroencephalogram findings that were consistent with juvenile myoclonic epilepsy. Among the 45 children randomly assigned, 74% had generalized spike, polyspike, and/or generalized spike and wave discharges on routine electroencephalogram recordings; the remaining 26% of children had no electroencephalogram findings suggestive of partial epilepsy and a clear history consistent with primary generalized tonic-clonic seizures. Electroencephalogram findings were not significantly different between the lamotrigine and the placebo treatment groups. The median percentage decrease from baseline in primary generalized tonic-clonic seizures during the entire treatment period was 77% in the lamotrigine group and 40% in the placebo group (P = .044). The median primary generalized tonic-clonic seizure counts per month were 0.7 in the lamotrigine group and 3.6 in the placebo group during escalation (P = .008), 0.3 in the lamotrigine group and 2.0 in the placebo group during maintenance (P = .005), and 0.4 in the lamotrigine group and 2.5 in the placebo group during the entire treatment period (P = .007). Trends were noted during escalation and maintenance with a median percentage decrease in primary generalized tonic-clonic seizures during escalation of 72% in the lamotrigine group and 30% in the placebo group (P = .059), and 83% in the lamotrigine group and 42% in the placebo group during maintenance (P = .058). During the maintenance phase, 48% of lamotrigine patients were seizure free compared with 17% treated with placebo (P = .051). One patient from each treatment group discontinued from the study because of an adverse event; 1 patient who received lamotrigine experienced "disorientation"; and 1 patient who received placebo had a convulsion with apnea. No rashes occurred among patients taking lamotrigine or placebo. No patient experienced worsening of the intensity or frequency of myoclonus. CONCLUSIONS: Adjunctive lamotrigine therapy seems effective in controlling primary generalized tonic-clonic seizures among patients 2 to 20 years of age.

Blood homocysteine, folate and vitamin B-12 concentrations in patients with epilepsy receiving lamotrigine or sodium valproate for initial monotherapy.

To evaluate whether the administration of lamotrigine (LTG) or valproate (VPA) changes concentrations of plasma total homocysteine (tHcy), plasma and red-cell folate and plasma Vitamin B-12, we measured these indices in a total of 20 patients with epilepsy before and after a 32-week period of monotherapy of LTG or VPA. We found that the 32-week administration of a mean daily dose of 250mg LTG had no significant effect on any of the blood indices. On the other hand, the administration of a mean daily dose of 2070mg of VPA resulted in a 57% increase in plasma Vitamin B-12 concentrations over the baseline value and a 27% decline in plasma tHcy concentrations, although the mechanisms of such changes are unknown. Our data indicate that hyperhomocysteinemia may not be a serious clinical problem among patients with epilepsy, who receive either LTG or VPA.

A dosing algorithm for converting from valproate monotherapy to lamotrigine monotherapy in patients with epilepsy.

A dosing algorithm was used to guide the conversion of 77 patients with epilepsy (16 years of age) from valproate monotherapy through lamotrigine adjunctive therapy at 200mg daily to lamotrigine monotherapy at 500 mg daily in an open-label study comprising a lamotrigine escalation phase (8 weeks), a valproate withdrawal phase (6 weeks), and a lamotrigine monotherapy phase (4 weeks). The algorithm was designed to maintain stable trough concentrations of lamotrigine during valproate withdrawal to minimize seizure risk. Of the 77 patients, 11 prematurely withdrew for administrative reasons (noncompliance, consent withdrawn, loss to follow-up, protocol violation). Of the remaining 66 patients, 18 withdrew because of adverse events, and 48 completed the study. Among the 67 patients with at least one lamotrigine trough serum concentration after initiation of therapy (pharmacokinetic population), mean trough serum concentrations at the end of the lamotrigine escalation phase at a lamotrigine daily dose of 200 mg (7.9 microg/mL, SD = 3.3) did not differ significantly from values during the valproate withdrawal phase (8.7 microg/mL, SD = 3.5) and the lamotrigine monotherapy phase at a lamotrigine dose of 500 mg daily (7.2 microg/mL, SD = 3.3). A similar pattern of results was observed among the 34 patients who completed the study on lamotrigine (completer population). No serious rashes were reported, and the incidence of withdrawals because of decreased seizure control was low (n = 2, or 3%; both incidents were judged to be related to noncompliance). By employment of a four-step dosing algorithm, lamotrigine serum concentrations can be maintained at a stable level with favorable tolerability during a transition from lamotrigine 200mg daily as adjunctive therapy with valproate to lamotrigine monotherapy 500 mg daily.

Efficacy and tolerability of conversion to monotherapy with lamotrigine compared with valproate and carbamazepine in patients with epilepsy.

OBJECTIVE: This randomized, open-label study was designed to compare the efficacy and tolerability of lamotrigine monotherapy with those of valproate and carbamazepine monotherapy in patients with epilepsy whose seizures were uncontrolled on their prestudy antiepileptic drug monotherapy. METHODS: Patients meeting eligibility criteria were randomized 2:1 to lamotrigine:carbamazepine or lamotrigine:valproate. The treatment phase was divided into a 4-week dose-escalation phase (Weeks 1-4), during which lamotrigine, carbamazepine, or valproate was added to patient's prestudy monotherapy; an 8-week add-on phase (Weeks 5-12), during which patients were stabilized on both the study medication and their prestudy antiepileptic therapy; an 8-week withdrawal phase (Weeks 13-20), during which prestudy antiepileptic therapy could be withdrawn if clinically appropriate; and an 8-week monotherapy phase (Weeks 21-28), during which patients could be treated with study medication as monotherapy. RESULTS: The numbers of patients randomized to the carbamazepine and valproate arms of the study were 144 (98 lamotrigine, 46 carbamazepine) and 158 (105 lamotrigine, 53 valproate), respectively. Successful monotherapy sustained for at least 7 weeks was achieved in comparable percentages of patients in the lamotrigine group (56%) and the carbamazepine group (54%) and in more patients in the lamotrigine group (49%) than the valproate group (40%). Among monotherapy completers, the percentage of patients with zero seizures during the monotherapy phase was comparable for lamotrigine (41%) and carbamazepine (30%) and significantly higher (P<0.05) with lamotrigine (32%) than with valproate (11%). No differences between treatments were observed with respect to time to treatment failure or time to first seizure. Lamotrigine was also better tolerated than carbamazepine or valproate. CONCLUSION: Lamotrigine monotherapy was as effective as and better tolerated than carbamazepine or valproate monotherapy in patients whose seizures were uncontrolled on their prestudy antiepileptic drug monotherapy.

Lamotrigine monotherapy compared with carbamazepine, phenytoin, or valproate monotherapy in patients with epilepsy.

OBJECTIVE: This open-label study evaluated the efficacy and tolerability of lamotrigine monotherapy compared with monotherapy with conventional antiepileptic drugs in patients converting from previous monotherapy because of inadequate seizure control or unacceptable side effects. METHODS: This study was conducted in 26 neurology clinics and epilepsy centers throughout the United States. The study enrolled 115 patients with epilepsy converting from previous monotherapy because of inadequate seizure control or unacceptable side effects. Patients were randomized 1:1 to receive 24 weeks of lamotrigine monotherapy or monotherapy with a conventional antiepileptic drug (carbamazepine, phenytoin, or valproate based on physician's choice). Patients were converted during an

Lamotrigine versus valproate monotherapy-associated weight change in adolescents with epilepsy: results from a post hoc analysis of a randomized, double-blind clinical trial.

Recent trends toward obesity and associated health risks in children highlight the significance of weight gain as a side effect with certain antiepilepsy drugs. No previous study has prospectively compared, in adolescents, weight effects for two commonly used antiepilepsy drugs. We report results from a post hoc subanalysis of adolescent data from a randomized, double-blind study comparing weight effects of lamotrigine and valproate. Patients were > or = 12 years of age with new-onset partial or generalized seizures who were randomized 1:1 to lamotrigine or valproate. Patients were escalated to a dose range of 100 to 500 mg/day for lamotrigine and 10 to 60 mg/kg/day for valproate based on clinical response, with target doses maintained for 24 weeks. Results are reported for adolescents aged 12 to 20 years. Weight changes during maintenance were higher (P < .05) in valproate (n = 20) patients than in lamotrigine (n = 18) patients, and change in body mass index was higher (P < .05) in valproate patients at the end of the study. At week 32, mean body mass index in the valproate group was above the 85th percentile representing "at risk for overweight." Whereas weight remained stable in adolescents treated with lamotrigine, weight increased in those treated with valproate by week 10 of this study and continued to increase at the end of the study.

Lamotrigine monotherapy improves health-related quality of life in epilepsy: a double-blind comparison with valproate.

The effects of monotherapy with lamotrigine on health-related quality of life were compared with those of valproate monotherapy in a randomized, double-blind trial designed to evaluate treatment-emergent weight changes in patients with epilepsy. At the end of 8 months of treatment, significantly more patients using lamotrigine compared with valproate experienced quality-of-life improvements on the Health Perceptions (42% vs 15%), Energy/Fatigue (47% vs 28%), and Social Isolation (35% vs 16%) subscales of the Quality of Life in Epilepsy-89 (QOLIE-89) questionnaire (P<0.05). Compared with valproate-treated patients, lamotrigine-treated patients were four times more likely to experience improvement in Health Perceptions, 2.3 times more likely to experience improvement in Energy/Fatigue, and 2.8 times more likely to experience improvement in Social Isolation (P<0.05). These quality-of-life improvements are consistent with the improvements in mood measured with the Beck Depression Inventory, the Cornell Dysthymia Rating Scale, and the Profile of Mood States among patients receiving lamotrigine. These data show that lamotrigine monotherapy provides benefits over valproate monotherapy in improving several aspects of health-related quality of life in patients with epilepsy. The observation that quality-of-life improvements during lamotrigine monotherapy occurred concurrently with improvements in mood suggests that the quality-of-life and mood changes may be causally related.