Increasing Plasma Concentration Tolerability Study of Flunarizine in Comedicated Epileptic Patients

Twelve patients with intractable partial seizures [4 receiving carbamazepine (CBZ), 4 phenytoin (PHT), and 4 both] entered a study of the tolerability of flunarizine (FNR) at specified plasma concentrations. After an 8-week baseline period, a single-dose pharmacoki-netic study was performed for each patient to calculate a loading dose and maintenance dosage necessary to achieve a target plasma FNR concentration of 30 ng/ml. The first 8 patients received the loading dose (as divided doses) during a 1-week hospitalization and the maintenance dosage for the ensuing 8 weeks. These patients proceeded to treatment periods with target concentrations of 60 and then 120 ng/ml, using doses based on an assumed linear relation between dose and plasma concentration. The last 4 patients were studied only at the 120-ng/ml target level. Results indicated that this procedure successfully approximated target levels of 30 and 60 ng/ ml, but observed concentrations in the last period exceeded the 120-ng/ml target level and continued to increase with time, often necessitating a dosage reduction owing to intolerability. Calculated doses for a given target concentration varied by a factor of 12. The most frequently reported adverse experiences were sedation and increased fatigue; reports of dizziness, headache, and lethargy were also common. Based on this study, a target concentration of at least 60 but <120 ng/ml is recommended for a controlled clinical trial of the antiepileptic efficacy of FNR.     

Management Strategies for Refractory Localization-Related Seizures

Summary: Localization-related epilepsy, the most common type of seizure disorder, often provides major management problems. Five new antiepileptic drugs (AEDs) with different mechanisms of action have been licensed in the United Kingdom in the 1990s for adjunctive use in the management of poorly controlled partial seizures. These were, in chronologic order, vigabatrin, lamotrigine, gabapentin, topiramate, and tiagabine. Their practical deployment is explored here. Mention also is made of clobazam and acetazolamide. Combination therapy with two or even three AEDs having complementary pharmacologic effects can provide an essential contribution to the management of partial seizures. This article discusses some of the pharmacologic strategies used in treating patients with refractory localization-related epilepsy.     

Topiramate Monotherapy for Partial Onset Seizures

Summary: Purpose: Evaluation of topiramate (TPM) as monotherapy in patients with uncontrolled partial onset seizures.
Methods: A total of 48 patients were evaluated in a doubleblind, parallel-group trial. During a 56-day baseline period, patients had at least eight partial onset seizures while being treated with one or two standard antiepileptic drugs (AEDs). After 1–2 weeks of open-label treatment with TPM 100 mg/day, patients were randomly assigned, in equal proportions, to receive double-blind therapy with TPM 100 or 1,000 mg/day in a 5-week conversion and an 11-week monotherapy period. The study endpoint was completion of 112 study days (success) or fulfillment of one or more exit criteria: doubling of average 28- day or highest 2-day baseline seizure rate, a generalized tonic-clonic seizure (GTCS) if none had occurred at baseline, or significant prolongation of generalized seizure duration.
Results: Time until exit was longer (p = 0.002) and success frequency was higher (p = 0.005) with TPM 1,000 as compared with 100 mg/day. Seizure-rate reductions of 50, 75, or 100% were achieved by 46, 25, and 13% of the 1,000-mg/day group, respectively, as compared with 13, 8, and 0% of the 100-mg/day group, respectively. Most adverse events (AE) were mild or moderate in severity.
Conclusions: Monotherapy with TPM 1,000 mg/day for partial onset seizures with or without secondarily generalized seizures was effective, with a favorable safety profile.     

Pregabalin As Adjunctive Therapy for Partial Seizures

Summary:  The efficacy and safety of pregabalin as adjunctive therapy for patients with partial epilepsy with or without secondary generalization has been studied in three randomized, double-blind, placebo-controlled trials involving 1,052 patients. Patients (≥12 years of age) participating in the trials were highly refractory to treatment, experiencing at least six seizures and no 4-week seizure-free period during the 8-week baseline phase, even though 73% received at least two antiepileptic drugs and 23% received three. Each fixed-dose study was 12 weeks in duration. In Study 1, patients received pregabalin 50, 150, 300, or 600 mg/day given two times daily with no titration period. Studies 2 and 3 had a 1-week titration to dose levels of 150 and 600 mg/day given three times daily (Study 2), 600 mg/day given two times daily, and 600 mg/day given three times daily (Study 3). Pregabalin, at 150, 300, and 600 mg/day, was significantly superior to placebo in reducing seizure frequency with a clear dose–response relationship. Responder rates, defined as the percentage of patients with ≥50% reduction in seizure frequency from baseline, approached 50% at 600 mg/day. In the effective dose range (150–600 mg/day), seizure freedom in the last 28 days of treatment was 3–17%. There was no difference between two times daily and three times daily dosing regimens. Efficacy was apparent as early as week one. The most commonly reported adverse events were CNS related, and either mild or moderate in intensity and generally self limiting. Few patients (≤5% in any treatment group) discontinued due to lack of efficacy. These results indicate that pregabalin is highly effective as adjunctive therapy in the treatment of patients with partial seizures with or without secondary generalization.     

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.     

Efficacy and Tolerability of Vigabatrin in Children with Refractory Partial Seizures: A Single-Blind Dose-Increasing Study

Summary: The efficacy and tolerability of vigabatrin (VGB) in children with refractory partial epilepsy were assessed in a single-blind, add-on, fixed-sequence, placebo-controlled trial. After 1-month observation, the patients entered a 7-month treatment period that involved administration of placebo for 1 month followed by VGB at the initial dosage of 40 mg/kg/day, to be increased to 60 and 80 mg/kg/day at 2-month intervals if seizures persisted. Of the 46 children enrolled in the study, 7 dropped out prematurely due to lack of efficacy of the drug (n = 6) or increased seizure frequency (n = 1). In 11 patients who either became seizure-free (n = 3) or improved markedly (n = 8), treatment was completed at a dose <80 mg/kg/day. The average number of seizures per month in the 39 patients who completed the study decreased from 97 during placebo to 21,12, and 9 after 2, 4, and 6 months of VGB treatments respectively (p < 0.0001 at each time). Response to VGB remained statistically significant when dropouts were included in the evaluation. The number of patients who had <50% reduction in seizure frequency after 2, 4, and 6 months was 28, 33, and 35, respectively. Eight patients became seizure-free during the last 2 months of VGB treatment (3 at 40, 3 at 60, and 2 at 80 mg/kg/day, as compared with none during placebo treatment). Serum levels of associated antiepileptic drugs (AEDs) showed no signscant changes, except for serum phenytoin (PHT) concentration, which significantly (p < 0.01) decreased after VGB treatment. Increased appetite and sedation were observed in 17 and 11% of cases, respectively. VGB is effective in the management of refractory partial epilepsy in children, and in some patients a positive dose-response relationship appears to occur over the assessed dosing range.     

Efficacy of Nafimidone in the Treatment of Intractable Partial Seizures: Report of a Two-Center Pilot Study

Nafimidone is a potential new antiepileptic drug with a therapeutic profile in experimental animal seizure models similar to that of phenytoin (PHT). We report here the first clinical trial of nafimidone in epileptic patients. Twelve adult male patients with a mean of four or more medically intractable seizures per month were enrolled in a 14-week pilot study. Patients were stabilized on therapeutic levels of PHT and carbamazepine (CBZ) (nine patients) or on PHT alone (three patients) before entering a 4-week baseline period. Nafimidone, to a maximum dose of 600 mg/day, was added during 2 weeks in hospital. Patients were then evaluated weekly for 8 weeks. Eight patients experienced 33-98% improvement in seizure control. Three others did not show significant change in seizure frequency but experienced sufficient subjective improvement that they continued into long-term follow-up. One patient, who had a 63% improvement in mean weekly seizures during the pilot study, declined to continue. Thus, 10 patients entered long-term follow-up. Six of the 10 sustained 53 to greater than 99% improvement in seizure control compared with baseline over the course of 46-53 weeks of follow-up. Nafimidone had a marked inhibitory effect on the clearance of CBZ and PHT, resulting in higher plasma levels in nine patients. The possible role of the elevated CBZ levels in the apparent efficacy of nafimidone is discussed.     

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.     

Efficacy of Topiramate as Adjunctive Therapy in Refractory Partial Seizures: United States Trial Experience

Summary: In companion double-blind, placebo-controlled, dose-ranging trials performed in the United States, topiramate (TPM) daily target dosages of 200-1,000 mg/day were evaluated as add-on therapy in adults with refractory partial seizures with or without becoming secondarily generalized. Net reductions in median monthly seizure frequency (active drug minus placebo) with the most efficacious dosages of TPM were 35% in the low-dose trial and 40% in the high-dose trial. Substantial reductions in secondarily generalized seizures were also observed with TPM. TPM appears to be an efficacious new antiepileptic drug in the management of partial epilepsy.     

Prognosis of Partial Epileptic Seizures in the Adolescent

Actuarial analysis was applied to the notes of 235 patients having a partial seizure for the first time between the ages of 12 and 18 years to establish the best predictive indicators of outcome. Among the factors considered to affect significantly the outcome were the seizure type (elementary or complex symptomatology), the initial EEG, the seizure frequency, the etiological factors, and an association with generalized seizures. Sex, age of onset, and topography of EEG paroxysmal abnormalities had no significance. An algorithm allows the prediction of the prognosis of these seizures at two different times immediately after a first seizure in some cases and after a 1-year survey in others.     

Treatment Strategies for Myoclonic Seizures and Epilepsy Syndromes with Myoclonic Seizures

Summary:   Despite the availability of numerous treatment options, the diagnosis and treatment of myoclonic seizures continue to be challenging. Based on clinical experience, valproate and benzodiazepines have historically been used to treat myoclonic seizures. However, many more treatment options exist today, and the clinician must match the appropriate treatment with the patient's epilepsy syndrome and its underlying etiology. Comorbidities and other medications must also be considered when making decisions regarding treatment. Rarely, some antiepileptic drugs may exacerbate myoclonic seizures. Most epileptic myoclonus can be treated pharmacologically, but some cases respond better to surgery, the ketogenic diet, or vagus nerve stimulation. Because myoclonic seizures can be difficult to treat, clinicians should be flexible in their approach and tailor therapy to each patient.     

Lamotrigine Therapy for Partial Seizures: A Multicenter, Placebo-Controlled, Double-Blind, Cross-Over Trial

Summary: The efficacy and safety of lamotrigine (LTG), a new antiepileptic drug (AED), were evaluated in a multicenter, randomized, double-blind, placebo-controlled, cross-over study of 98 patients with refractory partial seizures. Each treatment period lasted 14 weeks. Most patients were titrated to a LTG maintenance dose of 400 mglday. Seizure frequency with LTG decreased by ≥50%, as compared with placebo, in one fifth of patients. Overall median seizure frequency decreased by 25% with LTG as compared with placebo (p < 0.001). With LTG, the number of seizure days decreased by 18% as compared with placebo (p < 0.01), and investigator global evaluation of overall patient clinical status favored LTG by 2: 1 (p = 0.013). Plasma LTG concentrations appeared to be linearly related to dosage. LTG had no clinically important effects on the plasma concentrations of concomitant AEds. Adverse experiences were generally minor and most frequently were CNS-related (e.g., ataxia, dizziness, diplopia, headache). Most were transient and resolved without discontinuing treatment. Five patients withdrew as a result of adverse experiences while receiving LTG, including 3 patients with rash. One placebo patient was also withdrawn because of rash. The addition of twice-daily LTG to an existing AED regimen was safe, effective, and well tolerated in these medically refractory partial seizure patients.     

Gabapentin as Add-On Therapy in Children with Refractory Partial Seizures: A 12-Week, Multicentre, Double-Blind, Placebo-Controlled Study

PURPOSE: To evaluate the efficacy and safety of gabapentin (Neurontin; GBP) as add-on therapy for refractory partial seizures in paediatric patients aged 3-12 years. METHODS: After a 6-week baseline period, 247 patients (54 centres) entered a 12-week double-blind phase and were randomized to receive either GBP (t.i.d., titrated to 23-35 mg/kg/ day) or placebo. Seizure activity and type were recorded daily. Efficacy variables included Response Ratio (RRatio), responder rate, and percentage change in frequency (PCH) for all partial seizures; PCH and RRatio for individual types of partial seizures; and investigator and parent/guardian global assessments of seizure frequency and patient well-being. RESULTS: RRatio for all partial seizures was significantly lower (better) for GBP-treated patients (p = 0.0407). Responder rate favored GBP, but the difference between treatment groups was not statistically significant. Median PCH for all partial seizures for the GBP treatment group (-17.0%) was better than that for the placebo group (-6.5%). Median PCH for specific seizure types showed GBP to be most effective in controlling complex partial seizures (-35%) and secondarily generalized seizures (-28%) when compared with placebo (-12%, +13%, respectively). A greater percentage of GBP-treated patients exhibited improvement according to investigator and parent/guardian global assessments, with a statistically significant difference observed in the parent/guardian global assessment of seizure-frequency reduction (p = 0.046). Three GBP patients and one placebo patient were seizure free during the double-blind treatment period. GBP was well tolerated. CONCLUSIONS: GBP was effective and well tolerated as an add-on therapy for partial seizures in paediatric patients with previously drug-resistant seizures.     

Efficacy and tolerability of levetiracetam 3000 mg/d in patients with refractory partial seizures: a multicenter, double-blind, responder-selected study evaluating monotherapy. European Levetiracetam Study Group

PURPOSE: To evaluate the efficacy and tolerability of levetiracetam (LEV) monotherapy in selected patients with refractory partial seizures. METHODS: In this multicenter, double-blind, placebo-controlled, parallel-group, responder-selected study, patients were randomized (2:1 ratio) to receive oral LEV 1500 mg twice daily or placebo during a 12-week add-on phase. Treatment responders (patients with a reduction in partial seizure frequency of 50% or more compared with baseline) entered a monotherapy phase that included a maximum 12-week down-titration period and 12 weeks of monotherapy at 1500 mg twice daily. In both phases, responder rate, seizure frequency, and adverse events were analyzed. RESULTS: A total of 286 patients (placebo, n = 105; LEV, n = 181) entered the add-on phase, and 86 patients (placebo, n = 17; LEV, n = 69) were eligible for the monotherapy phase. Thirty-six of 181 patients (19.9%) who received LEV completed the entire study compared with only 10 of 105 patients (9.5%) in the placebo group (p = 0.029). The odds of completing the study on LEV were 2.36 times (95% confidence interval, 1.08, 5.57) higher than on placebo. The responder rate during the add-on phase was significantly higher in the LEV group compared with the placebo group (42.1% vs. 16.7%, respectively; p < 0.001). In the LEV monotherapy group, the median percent reduction in partial seizure frequency compared with baseline was 73.8% (p = 0.037), with a responder rate of 59.2%. Nine patients (18.4%) remained seizure-free on LEV monotherapy. CONCLUSIONS: Conversion to LEV monotherapy (1500 mg twice daily) is effective and well tolerated in patients with refractory partial seizures who responded to 3000 mg/d LEV as add-on therapy.     

Rufinamide for the adjunctive treatment of partial seizures in adults and adolescents: A randomized placebo-controlled trial

Purpose:   To evaluate efficacy and safety of adjunctive treatment with rufinamide 1600 mg twice daily in subjects aged ≥16 years with refractory partial seizures.
Methods:   This double-blind, placebo-controlled, randomized, parallel-group, multicenter trial included an 8-week baseline phase and a 13-week double-blind phase. Treatment was initiated with rufinamide 400 mg twice daily or placebo; rufinamide was titrated to 1600 mg twice daily. Percentage change in partial seizure frequency was the primary outcome measure. Secondary outcome measures included total partial seizure frequency and the percentage of subjects experiencing a ≥50% reduction in partial seizure frequency.
Results:   Three hundred thirteen subjects were randomized; 156 subjects received rufinamide and 157 received placebo. Rufinamide-treated subjects experienced a 20.4% median reduction in partial seizure frequency relative to baseline, while placebo-treated subjects had an increase of 1.6% (p = 0.02). Exclusion of subjects taking carbamazepine in a post hoc analysis resulted in a reduction of 29.2% versus 0.7% in the placebo group (p = 0.05), whereas the treatment difference in subjects taking carbamazepine was not significant. Of rufinamide-treated subjects, 28.2% experienced a ≥50% decrease in partial seizure frequency versus 18.6% of placebo-treated subjects (p = 0.04). The most common adverse events associated with rufinamide treatment were dizziness, nausea, diplopia, and ataxia; they occurred primarily during the titration phase.
Discussion:   Adjunctive therapy with rufinamide 3200 mg/day compared with matching placebo demonstrated efficacy and was generally well tolerated in adults with partial seizures. Further study of this agent in adults with partial seizures taking a range of baseline AEDs is warranted.     

Tiagabine: Efficacy and Safety in Adjunctive Treatment of Partial Seizures

PURPOSE: To assess the efficacy and safety of tiagabine (TGB), a new antiepileptic drug (AED), as add-on therapy in patients with refractory partial seizures. METHODS: This response-dependent study used an open-label screening phase (in which patients were titrated to their optimal TGB dose, < or =64 mg/day) followed by a double-blind, placebo-controlled, crossover phase. Initial eligibility criteria included (a) seizures inadequately controlled by existing AEDs, and (b) six or more partial seizures during an 8-week baseline period. Patients showing benefit from TGB (> or =25% reduction in total seizure rate relative to baseline) were eligible for randomization into the double-blind phase, which comprised two 7-week assessment periods separated by a 3-week crossover period. RESULTS: Forty-four (50%) of the 88 enrolled patients entered the double-blind phase of the study during which there were significant reductions compared with placebo in all partial (p < 0.01), complex partial (p < 0.001), and secondarily generalized tonic-clonic seizure rates (p < 0.05). Thirty-three percent of patients experienced a reduction of > or =50% in the all partial seizure rate. Eight (22%) patients receiving TGB during the double-blind phase reported adverse events, of which dizziness and incoordination were the most frequent. Three patients withdrew from treatment during the double-blind phase because of adverse events; two during treatment with TGB and one during treatment with placebo. TGB did not affect plasma concentrations of other coadministered AEDs. CONCLUSIONS: TGB was significantly better than placebo in terms of seizure rate reduction and was generally well-tolerated in patients with difficult to control seizures.     

Dose–Response Study of Vigabatrin as Add-On Therapy in Patients with Uncontrolled Complex Partial Seizures

Summary: Purpose: This placebo-controlled, randomized, double-blind, multicenter study examined the efficacy and safety of three daily doses of vigabatrin (VGB; 1, 3, or 6 g) as add-on therapy in 174 patients with previously uncontrolled complex partial seizures with or without secondary generalization.
Methods: A 12-week pretreatment assessment period was followed by drug therapy with a 6-week titration period and a 12-week maintenance phase.
Results: VGB doses of 3 and 6 g/day reduced median monthly frequency of seizures by 4.3 and 4.5 seizures, respectively, compared with 0.2 seizures for placebo (p = 0.0001). The percentages of patients classified as therapeutic successes (≤50% reduction in seizure frequency) were 7% for placebo and 24, 51, and 54% for patients taking daily VGB doses of 1, 3, and 6 g, respectively; the comparison with placebo was significant for all treatment groups. The linear trend for dose response was highly significant (p ≥ 0.0001) for both median monthly seizure frequency and therapeutic success. Vigabatrin was well tolerated, causing no clinically significant changes in laboratory parameters, brain magnetic resonance imaging, evoked potentials, cognitive function, or psychosocial tests. Fatigue, drowsiness, and dizziness were the most common treatment-related adverse events in all treatment groups. Dropouts due to adverse events were higher in the 6-g/day group.
Conclusions: VGB was significantly more effective than placebo as add-on therapy in reducing seizure frequency. VGB at 3 and 6 g/day produced the best efficacy: however, adverse events may limit the use of the 6-g/day dose in some patients.