A Pharmacoepidemiologic Study of Factors Influencing the Outcome of Treatment with Lamotrigine in Chronic Epilepsy

PURPOSE: To identify prognostic factors for freedom from seizures and long-term retention of treatment in patients receiving lamotrigine (LTG). METHODS: A multicenter, retrospective, case record study of 1,050 patients with chronic epilepsy was carried out. Logistic regression and Cox regression analyses were used to identify clinical features associated with freedom from seizures and retention of treatment, respectively. Long-term retention rates of LTG therapy were estimated using Kaplan-Meier survival analysis. RESULTS: The 1,050 patients with chronic epilepsy were included in the study. Patients with generalized epilepsy (p = 0.01), who were not receiving carbamazepine (CBZ; p = 0.02) were more likely to become seizure-free. Sixty percent of patients continued on LTG therapy >1 year and estimated retention at 8 years was 38%. Patients with generalized epilepsy (p = 0.002), patients receiving concurrent sodium valproate (VPA; p < 0.0001), those not previously exposed to gabapentin and vigabatrin (p < 0.0001), and those in whom the starting dose was lower (p < 0.0012), were more likely to remain on long-term treatment with LTG. The relationships with exposure to other antiepileptic drugs remained significant in patients with focal and with generalized epilepsy when considered separately. CONCLUSIONS: The best results from LTG treatment in terms of freedom from seizures and long-term retention of treatment were obtained in patients with generalized epilepsy. Retention of treatment was enhanced by VPA not only in generalized but also in focal epilepsy. The importance of a low starting dose of LTG was again confirmed. The apparent negative effect of CBZ in patients taking LTG merits further investigation.     

Role of Vigabatrin and Lamotrigine in Treatment of Childhood Epileptic Syndromes

Summary: Purpose: Vigabatrin (VGB) and lamotrigine (LTG) are two new antiepileptic drugs (AEDs) with different mechanisms of action for treatment of refractory epilepsies. Previous reports have indicated efficacy of both drugs in a number of epileptic syndromes.
Methods: We compared these new AEDs drugs to determine their respective efficacy against different types of epileptic syndrome and to develop a rational approach to their use. We reviewed the charts of 105 children, with partial and generalized epilepsies.
Results: VGB was to be significantly more effective in children with partial epilepsies, and LTG was more effective in those with generalized epilepsies.
Conclusions: VGB and LTG have different therapeutic profiles. Combination treatment with the two drugs may represent rational polytherapy for patients with epilepsy resistant to treatment with either drug alone or as add-on to other AED treatment.     

Gabapentin versus vigabatrin as first add-on for patients with partial seizures that failed to respond to monotherapy: a randomized, double-blind, dose titration study. GREAT Study Investigators Group. Gabapentin in Refractory Epilepsy Add-on Treatment

PURPOSE: Our objective was to compare the efficacy and safety of gabapentin and vigabatrin as first-line add-on treatment in patients with partial epilepsy. METHODS: This was a multicenter, double-blind, randomized dose titration study. After baseline assessment and randomization, the dose could be increased if seizures persisted and reduced if side effects occurred. Health-related quality of life was assessed at baseline and at the end of the study. By a protocol amendment post hoc, all randomized patients were offered a standardized perimetry examination at the end of the study. Improvement rate was the proportion of patients with a reduction of seizure frequency of at least 50% during an 8-week period without any adverse events causing withdrawal. RESULTS: One hundred two patients were randomized and analyzed on an intent-to-treat basis. The improvement rate was 48% in the gabapentin group and 56% in the vigabatrin group. The improvement rate, when per protocol criteria were fulfilled, was 57% in the gabapentin group and 59% in the vigabatrin group. The proportion of seizure-free patients was 31% in the gabapentin group and 39% in the vigabatrin group. There was no difference in quality-of-life scores between the groups. Perimetry after termination of the study on 64 patients showed abnormal results in 3 of 32 patients in the vigabatrin group. CONCLUSION: Approximately one third of the patients in both groups became seizure-free. Although no major differences were seen in terms of the improvement rate between the groups, equivalence between the two drugs was not found.     

Utility of the Lethargic (lh/lh) Mouse Model of Absence Seizures in Predicting the Effects of Lamotrigine,Vigabatrin, Tiagabine,Gabapentin, and Topiramate Against Human Absence Seizures

Summary: Purpose: Traditional methods of preclinical screening have predicted the effects of a putative antiepi-leptic drug (AED) against human absence seizures by testing its efficacy against clonic seizures in the high-dose pen-tylenetetrazole (PTZ) model. This high-dose PTZ model correctly predicted the efficacy of ethosuximide (ESM), benzodiazepines, and valproate (VPA) and the lack of efficacy of phenytoin (PHT) and carbamazepine (CBZ). However, the high-dose PTZ model erred in predictions for (a) phenobarbital (PB) (PTZ: efficacy; human: noneffi-cacy); (b) lamotrigine (LTG) (PTZ nonefficacy; human: efficacy); (c) vigabatrin (VGB) (PTZ: nonefficacy; human: proabsence effect); and (d) tiagabine (TGB) (PTZ efficacy; human: possibleproabsence). It also appears to have erred in predictions for gabapentin (GBP) (PTZ efficacy) and topiramate (TPM) (PTZ: efficacy). Because the lh/lh genetic model of absence seizures correctly predicted effects of ESM, clonazepam, VPA, PHT, CBZ, and PB against human absence seizures, we performed this study to test the predictive utility of the lWZh model for LTG, VGB, TGB, GBP, and TPM. Methods: Bipolar recording electrodes were implanted bilaterally into frontal neocortex of 8–week-old male lWZh mice. With the exception of VGB, vehicle or drugs were administered intraperitoneally (i.p.) on alternating days, and an EEG was used to record effects on seizure frequency. With VGB, vehicle was administered i.p. on day 1, and gradually increasing doses of VGB were administered on successive days. Drug and vehicle effects were compared in corresponding lfi-min epochs of the 150–min period after administration. Results: LTG (4.8–144 μmol/kg) significantly (p < 0.04) reduced seizure frequency (by 6.5%) compared with vehicle. In contrast, VGB (0.35–11 mmol/kg) and TGB (0.27–27 μmol/kg) significantly increased seizure frequency (300– 700%) and seizure duration (1,700–1,800%; p ≤ 0.001). GBP (18μmol/kg to 1.8 mmol/kg) and TPM (8.9–29.5 pmol/kg) had no significant effect on seizure frequency. Conclusions: In contrast to the high-dose PTZ model, the lh/lh model correctly predicted the antiabsence effect of LTG, the possible proabsence effects of VGB and TGB, and the lack of effect of GBP and TPM. The lWlh model appears to be superior to the high-dose PTZ model in predicting efficacy of putative AEDs against human absence seizures.     

Lamotrigine and Seizure Aggravation in Severe Myoclonic Epilepsy

Summary: Purpose: In severe myoclonic epilepsy of infancy (SME), multiple drug-resistant focal and generalized seizure types occur. Lamotrigine (LTG), found effective in many generalized and partial seizures, has been little used in severe childhood epilepsy syndromes with multiple seizure types. We studied the effects of LTG in SME.
Methods: Twenty-one patients with SME, aged 2–18 years, were treated with LTG, 20 in add-on and one in monotherapy. LTG was started at 0.2–2.5 mg/kg/day and increased to 2.5–12.5 mg/kg/day. For each seizure type, excluding atypical absences, >50% variations compared with the 2 months preceding LTG were considered indicators of response, also taking into account the degree of disability each seizure type produced.
Results: LTG induced worsening in 17 (80%) patients, no change in three, and improvement in one. There was >50% increase in convulsive seizures in eight (40%) of 20 patients. Myoclonic seizures worsened in six (33%) of 18 patients. Of five patients improving in at least one seizure type, four had concomitant worsening of more invalidating seizures. Clear-cut worsening appeared within 3 months in most patients but was insidious in some. LTG was suspended in 19 patients after 15 days-5 years (mean, 14 months) with consequent improvement in 18.
Conclusions: The pronounced seizure deterioration during LTG treatment was not attributable to the natural course of the disease and could be a direct effect of therapeutic LTG doses. LTG treatment seems inappropriate in SME.     

Oral Gabapentin Disposition in Patients with Epilepsy After a High-Protein Meal

Summary: Purpose: To study the interaction between gaba-pentin (GBP) and high-protein meals, 12 patients with epilepsy were administered this drug both while in a fasting state and after a high-protein meal.
Methods : After having acquired their informed consent, the patients (suffering from partial complex seizures resistant to other anticonvulsants) were randomly assigned to 2 groups of 6 subjects. Each subject was treated in a fasting state with a single 400 (group A) or 800 (group B) mg GBP oral dose. After 24 h, the GBP dose regimen was repeated, but was given after a high-protein meal. Serum GBP concentrations were measured by LC-Mass at baseline and 0.5, 1, 2, 3, 5, 7, 9, 12, and 24 h. Saliva GBP concentrations were determined at baseline and 2, 4, 8, and 12 h. GBP urinary excretion was determined at 0–4, 4–8, and 8–12 h intervals. The following kinetic parameters were calculated: area under the concentration time curve from zero time to 24 h after the dose, AUC 0–24 h; maximal serum concentration, C_max; time to the maximal serum concentration, T_max; absorption rate constant, ka; elimination rate constant, p; elimination half-time, t½β. Student's t test for paired data, with significance assigned at P < 0.05, was used.
Results : No statistically significant differences were seen in GBP serum or saliva concentrations or in its urinary excretion (both in A or B group) between fasting and after the high-protein meal.
Conclusions : High-protein meals do not seem to interfere with oral disposition of GBP.     

Open, Double-Blind and Long-Term Study of Vigabatrin in Chronic Epilepsy

We performed an open, double-blind, and long-term study of vigabatrin (gamma-vinyl-GABA, GVG) in patients with treatment-resistant epilepsy who were receiving only one or at most two standard antiepileptic drugs (AEDs). The novel design included a parallel, double-blind, placebo-controlled phase that minimized the number of patients receiving placebo and allowed determination of the optimum dose of GVG for each patient before initiation of the double-blind phase. The study was divided into four phases. The first phase was a 6-week period of baseline observation. In the second phase, GVG was added openly to previous AEDs for 8 weeks. During the first 2 weeks of this phase, the dose of GVG was increased weekly and then, in the absence of adverse effects, was held constant for the next 6 weeks. At the end of this open phase, seizure frequency during the 6 weeks of constant treatment was compared with the baseline seizure frequency for each patient. Patients who experienced reduction greater than 50% in the frequency of any seizure type during the open phase were defined as responders. These responders were then entered into the third and double-blind phase, in which they were randomly allocated wither to continue active GVG treatment or placebo for 8 weeks. Thirty-three patients entered the study; 31 of 33 patients completed the initial open phase. Twenty patients achieved a reduction greater than or equal to 50% in the frequency of one or more seizure types and were eligible for the double-blind phase; 10 were randomized to continue GVG and 10 were randomized to placebo.(ABSTRACT TRUNCATED AT 250 WORDS)     

Aggressive Behaviour in Intellectually Challenged Patients with Epilepsy Treated with Lamotrigine

Summary: Purpose: Lamotrigine (LTG) is a valuable addition to the medical management of epilepsy with wide spectrum of efficacy and good outcomes for quality of life. We report the emergence of a syndrome of aggressive behavior provoked by LTG in patients with epilepsy and intellectual challenge.
Methods: On recognition of a tendency to aggression in intellectually challenged patients whose epilepsy was treated with LTG, a survey was conducted of those from centers specializing in management of patients with intellectual disability who were treated with LTG. Responses to LTG were sought and patient's behavioral profiles were determined.
Results: Nineteen patients were identified (16 men, 3 women, aged 17–54 years). Five patients discontinued LTG due to unprovoked aggressive behavior subsequent to its use; 2 had aggressive behavior sufficient to justify discontinuation of LTG but required reintroduction to control the epilepsy; 1 required reduction in LTG dosage; 1 had aggression that responded to psychiatric intervention; and I had aggression unrelated to LTG. Four patients had behavioral problems other than aggression, 4 had no change in behavior, and the behavior of 1 was improved by LTG treatment.     

Conversion to High Dose Gabapentin Monotherapy in Patients with Medically Refractory Partial Epilepsy

Summary: Purpose: To evaluate the safety and efficacy of high dose gabapentin (GBP) monotherapy (3,0004,800 mg/ day) in patients with medically refractory partial epilepsy.
Methods: GBP monotherapy at daily doses up to 4,800 mg was attempted in patients participating in the open-label phase of a double-blind, dose-controlled, GBP monotherapy trial. For those who achieved monotherapy, the types and severity of adverse events were assessed and the average seizure frequency per 28 days while maintained on the highest daily GBP dose was compared to the seizure frequency during the baseline phase of the double blind trial. Correlation analysis between GBP serum level, total daily dose, and percentage of seizure change from baseline was performed.
Results: A total of 45 patients participated in the open-label phase of the trial and 23 (51%) were converted successfully to GBP monotherapy. In those patients, the average daily gabapentin dose was 3,900 mg and the mean length of follow-up was 252 days. Compared to baseline, there was a mean reduction of 54%, 43%, and 14% for simple partial, complex partial and secondarily generalized seizures respectively, while maintained on high-dose GBP monotherapy. A significant linear correlation between daily GBP dosage (2,4004,800 mg) and resultant mean serum levels was found (r = 0.51; p < 0.01). There was no significant correlation between seizure frequency and total daily GBP dose or with serum levels. High-dose GBP monotherapy was well tolerated; only one patient exited the trial because of adverse events. The most common adverse event was tiredness/sleepiness and was not dose-related.
Conclusions: GBP monotherapy is well tolerated in daily doses of up to 4,800 mg and is effective in a subgroup of patients with medically refractory partial epilepsy.     

Comparison of Cognitive Effects of Lamotrigine and Oxcarbazepine in Epilepsy Patients

Background and Purpose

This study compared the cognitive effects of 1 year of treatment with lamotrigine (LTG) and oxcarbazepine (OXC) in epilepsy patients.

Methods

This retrospective study investigated 60 epilepsy patients undergoing neuropsychological tests who were either newly diagnosed or untreated in the preceding 6 months. The cognitive function in 30 patients receiving LTG monotherapy and 30 age-matched patients receiving OXC monotherapy was compared after 1 year. The neuropsychological scores at baseline and all of the epilepsy-relevant variables except seizure type did not differ between the groups. The mean daily dosages of LTG and OXC at 1 year were 93 mg and 825 mg, respectively.

Results

The posttreatment list-learning performance was better in the LTG group than in the OXC group (p<0.05). The incidence of cognitive complaints did not differ between the two groups. The list-learning performance and Trail Making Test scores were better in each group after treatment.

Conclusions

LTG and OXC monotherapies have similar, slightly beneficial effects on cognitive function, and are probably not harmful.     

A Beneficial Effect on Mood in Partial Epilepsy Patients Treated with Gabapentin

PURPOSE: Antiepileptic drugs (AEDs) are frequently used for their beneficial psychoactive effects on affective disorders. We sought to demonstrate a psychoactive effect of gabapentin (GBP) when used as add-on AED therapy. METHODS: Forty adult patients with partial epilepsy were studied in a prospective, non-randomized fashion with interviewer-rated and self-rated scales of mood and anxiety: the Cornell Dysthymia Rating Scale (CDRS), Beck Depression Inventory (BDI), and Hamilton Depression (Ham-D) and Anxiety (Ham-A) Scales. After completion of baseline mood and anxiety scales (time 1), 20 of the 40 patients were prescribed add-on GBP (treated group). The remaining 20 patients served as a control group. Both groups were similar in age and sex distribution. Follow-up mood and anxiety scales were performed in all patients approximately 3 months later (time 2). The average GBP dose at time 2 was 1,615 mg/day. All patients were taking stable doses of one to four AEDs at baseline and throughout the study. Seizure frequency was monitored throughout. Statistical significance was assessed by analysis of variance (ANOVA) by using a two-factor repeated-measures model. RESULTS: The GBP-treated group had a significant decrease in CDRS score over time compared with the control group (p = 0.04). No significant differences between the control and the treated groups were found for any of the remaining mood scales (BDI, p = 0.58; Ham-D, p = 0.59; Ham-A, p = 0.93). There was no significant difference or change in seizure frequency between groups. CONCLUSIONS: GBP treatment is associated with mood improvement as measured by the CDRS. This improvement was not accounted for by seizure improvement.     

Positive and Negative Psychotropic Effects of Lamotrigine in Patients with Epilepsy and Mental Retardation

Summary: Purpose: To describe significant positive or negative psychotropic effects of lamotrigine (LTG) observed in epilepsy patients with mental retardation (MR).
Methods: Seven mentally retarded epilepsy patients, [5 with Lennox-Gastaut syndrome (LGS)] who experienced significant behavioral improvements or worsening after addition of LTG to their medication regimen were studied.
Results: LTG produced behavioral improvements in 4 patients. Patient 1, a 14-year-old girl, had LTG added to valproate (VPA) and thioridazine, resulting in diminished lethargy, less hyperactivity, and more appropriate speech. In a 17-year-old boy (patient 2) LTG added to VPA, phenytoin (PHT), and gabapentin (GBP) lessened irritability and hyperactivity. In patient 3, a 41-year-old woman, LTG added to PHT, VPA, and carbamazepine (CBZ) diminished lethargy and enhanced her social interactions. In patient 4, a 27-year-old man, LTG monotherapy diminished irritability and hyperactivity. Adverse behavioral effects were noted in 3 patients. In patient 5, a 43- year-old man, LTG added to PHT, phenobarbital (PB), lorazepam, sertraline, and thioridazine produced irritability, hyperactivity, and poor cooperation. In patient 6, a 29-year-old woman, LTG added to VPA produced frequent screaming, temper tantrums, increased rocking movements, and hyperactivity. In patient 7, a 29-year-old man, LTG added to VPA and PHT resulted in severe exacerbation of baseline behaviors, including self-injurious activity, temper tantrums, and failure to obey simple instructions.
Conclusions: In some patients with epilepsy and MR, LTG has significant positive or negative effects on behavior.     

Lamotrigine therapy of epilepsy with Angelman's syndrome

PURPOSE: Angelman syndrome (AS) is a neurogenetic disorder characterized by developmental delay and a frequently refractory epileptic condition. Valproate, clonazepam and/or phenytoin are said to be the most effective antiepileptic drugs (AEDs) against the seizures in AS. Experience with the newer AEDs is very limited despite their better safety profile and tolerability. Considering its favorable side effect profile and its effectiveness against both partial and generalized seizures, we hypothesized that lamotrigine (LTG) might be more efficacious and better tolerated. METHODS: Potential patients for this retrospective study were identified from the epilepsy clinics at Notre-Dame, Sainte-Justine, and Yale New Haven hospitals. Patients were included in the study if they had AS along with refractory seizures. The medical record of each patient was reviewed with interest on seizure types, previous AEDs and response to LTG. RESULTS: Five patients (2M, 3F) were included in this study. Age at LTG ranged from 10 to 33 years old. All had >or=2 seizure types, mainly generalized tonic-clonic, myoclonic seizures, and atypical absences. Previously tried AEDs included valproic acid (5), benzodiazepines (5), phenytoin (4), carbamazepine (3), and topiramate (1). One patient had pancreatitis on phenytoin, one had worsened seizures on carbamazepine, and one developed hepatic encephalopathy on valproic acid. Three patients became seizure-free with LTG (9, 20, and 36 months FU), one was seizure-free for 1 year with subsequent loss of efficacy, and one showed >50% reduction in myoclonic seizures (20 months FU). No side effects were reported. CONCLUSION: LTG can be efficacious and well tolerated in patients with AS.     

Vigabatrin in the Treatment of Epilepsy: A Double-Blind, Placebo-Controlled Study

The efficacy and tolerability of vigabatrin (gamma-vinyl GABA, GVG), given as add-on therapy to 23 adult outpatients with severe drug-resistant epilepsy (17 with partial seizures), were studied using a double-blind, placebo-controlled, crossover design. The study consisted of two 7-week periods during which vigabatrin and placebo were administered in random sequence. Dosage was 1.0 g twice daily for patients weighing less than or equal to 65 kg and 1.5 g twice daily for patients weighing greater than 65 kg. Three patients were dropped from the study, two for reasons unrelated to treatment and one because of the appearance of vertigo, headache, dysarthria, and ataxia, which subsided rapidly when vigabatrin was stopped (3 g daily). Sixteen of the 20 patients available for analysis showed a decrease in the total number of seizures as compared with the placebo period. Of these, 12 showed a greater than 50% reduction in seizure frequency and 4 of the 12 showed a greater than 75% reduction. Both the total number of seizures and the number of partial seizures were significantly reduced by vigabatrin (p less than 0.01). Only in the patient who dropped out were severe adverse effects seen. The most frequently reported unwanted effect was mild drowsiness, which developed in seven patients on vigabatrin and in one on placebo. Positive effects, however, were also seen with six patients who reported an improved sense of well-being while receiving vigabatrin as compared with only 1 during the placebo period. No consistent changes in electrocardiogram (ECG), electroencephalogram (EEG), and visual-, auditory-, and somatosensory-evoked potentials were seen during the study.(ABSTRACT TRUNCATED AT 250 WORDS)     

Lamotrigine High-Dose Tolerability and Safety in Patients with Epilepsy: A Double-Blind, Placebo-Controlled, Eleven-Week Study

Summary: Purpose: This study was undertaken to evaluate the dose tolerability and safety of a chronic ascending twice-daily (b.i.d.) dosage regimen of 700 mg/day larnotrigine (LTG) and to include determination of the LTG pharmacokinetic profile at doses 500 mg/day in patients receiving concomitant enzyme-inducing antiepileptic drugs (AEDs). Methods: Twelve adult male epileptic patients treated with enzyme-inducing AEDs received 700 mg/day (b.i.d.) oral LTG (n = 8) or placebo (controls, n = 4). For 3 weeks, as outpatients they had their LTG dosage increased from 100 to 400 mg/day. Then, in a clinical research study unit, patients received regimens of 500, 600, and 700 mg/day for 1 week each. Controls received matching placebo in the same sequence. At study end, dosages were tapered in 2 weeks. Follow-up evaluations were made 7 days later. Results: Five LTG patients tolerated 700 mg/day for 1 week. LTG was reduced to 600 mg/day in a patient with mild diplopia and to 500 mg/day in a patient with mild oscillopsia and diplopia. One patient discontinued 300-mg/day therapy with a moderately intense diffuse papular skin rash, attributed to LTG. Headache, drowsiness, faintness, and diplopia, the common adverse events (AEs), were mild to moderate in intensity and occurred in 50–75% of patients in both groups (except for diplopia, occurring only with LTG). Concomitant AED plasma concentrations were not markedly changed by LTG. LTG pharmacokinetics were linear over the range of 500–700 mg/day. Conclusions: LTG doses 700 mg/day can be tolerated in patients receiving concomitant enzyme-inducing AEDs.     

Effects of Vigabatrin on Cognitive Function and Mood When Used as Add-on Therapy in Patients with Intractable Epilepsy

Cognitive function and mood of patients with epilepsy who received 2 g/day vigabatrin (GVG) in addition to their usual antiepileptic drugs (AEDs) was assessed on two occasions: before start of treatment (baseline) and 4 weeks after start of treatment. A battery of selected psychological tasks measuring attention, mental speed, motor speed, central cognitive processing, and perceptuomotor performance was used, along with standardized, objective mood assessments. A comparison group (n = 15) of patients receiving stable medication was also tested to evaluate practice effects of the psychometric tests. Administration of 2 g/day GVG significantly decreased response time on a test of central cognitive processing ability (arithmetic). No adverse effect was noted on any other test of cognitive function or mood.     

Double-Blind, Placebo-Controlled, Lamotrigine in Treatment-Resistant Generalised Epilepsy

Summary: Purpose : Lamotrigine (LTG) is recognised as effective add-on therapy for focal epilepsies, but this is the first double-blind, placebo-controlled, crossover study in treatmentresistant generalised epilepsy.
Methods: The study consisted of 2 × 8-week treatment periods followed by a 4-week washout period. Patients received doses of either 75 or 150 mg daily, depending on their concomitant antiepileptic drugs (AEDs). Long-term continuation was offered at the end of the study with open-label LTG.
Results: Five centres in Australia recruited 26 patients who were having absence, myoclonic, or generalized tonic-clonic seizures or a combination of these. Twenty-two patients completed the study. There was a significant reduction in frequency of both tonic-clonic and absence seizure types with LTG. A 250% decrease in seizures was observed for tonic-clonic seizures in 50% of cases and for absence seizures in 33% of evaluable cases. Rash was the only adverse effect causing discontinuation. Twenty-three of 26 opted for open-label LTG, with 20 still receiving LTG for a mean of 26 months. In these 20, 80% had 250% seizure reduction and five (25%) were seizure free.
Conclusions: This study shows that LTG is effective add-on therapy in patients with refractory generalised epilepsies. Statistically significant reduction in seizures in both absence and tonic-clonic seizure types was seen even with low doses of LTG.