Clinical experience with open-label topiramate use in infants younger than 2 years of age

Topiramate treatment in Wistar rats during childhood induces sex-specific vascular dysfunction in adulthood

The present study determined whether treatment during childhood with topiramate (TPM), a new generation antiepileptic drug, results in altered aortic reactivity in adult male and female rats. We also sought to understand the role of endothelium-derived contractile factors in TPM-induced vascular dysfunction. Male and female Wistar rats were treated with TPM (41 mg/kg/day) or water (TPM vehicle) by gavage during childhood (postnatal day, 16-28). In adulthood, thoracic aorta reactivity to phenylephrine (phenyl), as well as aortic thickness and expression of cyclooxygenases (COX-1 and COX-2), NOX2, and p47^phox were evaluated. The aortic response to phenyl was increased in male and female rats from the TPM group when compared with the control group. In TPM male rats, the hyperreactivity to phenyl was abrogated by the inhibition of NADPH oxidase and COX-2, while in female rats, responses were restored only by inhibition of COX-2. In addition, TPM male rats presented aortic hypertrophy and increased expression of NOX-2 and p47phox, while TPM female rats showed increased COX-2 aortic expression. Taken together, for the first-time, the present study provides evidence that treatment with TPM during childhood causes vascular dysfunction in adulthood, and that the mechanism underlying the vascular effects of TPM is sex-specific.

Efficacy and Tolerability of Second and Third Generation Anti-epileptic Drugs in Refractory Epilepsy: A Network Meta-Analysis

This study was proposed to compare the relative efficacy and tolerability of the second and third generation AEDs for refractory epilepsy. The 50% responder rate (RR) was selected as the efficacy outcome whereas the incidence of dizziness and somnolence were considered to evaluate the tolerability of AEDs. Odds ratio (OR) and their 95% credible interval (CrI) were obtained using a consistency model and surface under the cumulative ranking curve (SUCRA) value was calculated to rank AEDs. Topiramate appeared to be significantly more effective than placebo, eslicarbazepine acetate, perampanel, pregabalin, zonisamide, gabapentin and lamotrigine with respect to the 50% RR (all OR > 1). Patients who were managed by eslicarbazepine acetate, perampanel, oxcarbazepine, topiramate and pregabalin were more likely to suffer from dizziness compared to those who receive placebo (all OR > 1). Perampanel, topiramate and pregabalin were related to elevated risks of somnolence compared to placebo (all OR > 1). Moreover, topiramate ranked highest with respect to 50% RR (SUCRA = 0.968) whereas levetiracetam appeared to have balanced efficacy and tolerability (SUCRA = 0.769, 0.743, 0.604 and 0.659). In conclusion, topiramate was the most efficacious AED, while levetiracetam was able to provide patients with balanced efficacy and tolerability.

Efficacy of topiramate for intractable childhood generalized epilepsy with epileptic spasms: with special reference to electroencephalographic changes

PURPOSE

Epileptic spasms (ES) beyond infancy are a highly refractory type of seizures that require the development of an effective treatment. We therefore studied the efficacy and safety of topiramate (TPM), which is a drug that is indicated to be effective for intractable childhood epilepsy, for ES.

METHODS

Out of 58 children with ES, we enrolled 33 patients treated with TPM at ≤ 12 years of age. The administration of TPM was limited to cases of epilepsies that were resistant to any other potent treatment. We retrospectively investigated the efficacy of TPM for seizures and changes in electroencephalogram (EEG) findings.

RESULTS

The median age at the start of TPM treatment was 5 years, 8 months. All patients had ES and 28 also had tonic seizures. As for the efficacy of TPM for all seizures, five patients became seizure-free and two had a ≥ 50% reduction in seizures. Seizure aggravation was observed in six patients. Of 29 patients whose EEG findings were compared before and during TPM treatment, nine showed EEG improvement with reduced epileptic discharges. Adverse effects were observed in 13 patients and included somnolence, anorexia, and irritability. In general, TPM was well tolerated.

CONCLUSIONS

TPM can be effective at suppressing very intractable ES in a proportion of patients who do not respond to any other treatment. The efficacy of TPM may be predictable based on EEG changes observed early in the course of treatment. TPM is promising for the treatment of extremely intractable childhood epilepsy and it has largely tolerable adverse effects.

Effectiveness of topiramate in medically complicated patients with status epilepticus or acute refractory seizures

Background and Purpose:

The conventional therapeutic regimen for status epilepticus (SE) may require artificial ventilation and hemodynamic support, and is associated with significant complications and increased mortality. We investigated the safety and effectiveness of topiramate (TPM) in patients with refractory SE, who had medical complications such as systemic infection, renal dysfunction, hepatic dysfunction, and bone marrow suppression.

Methods:

We analyzed the clinical features and therapeutic outcome in 16 patients with GCSE, NCSE or recurrent GTC in whom TPM was administered for its control.

Results:

The majority of our patients had GCSE (n=6) or NCSE (n=7). The common co-morbid diseases at the onset of seizures were hematological disorders (pancytopenia 8, anemia 2, anemia with thrombocytopenia 2) and sepsis (n=8). Twelve patients were under the renal and/or hepatic dysfunction. Within a few days, 13 patients could experience their seizure control (the mean duration, 3.7± 2.6 days), but the seizures of the other subjects did not be terminated in spite of all efforts. No patients experienced a worsening of their CBC or blood chemistry profiles with the TPM treatment.

Conclusions:

We could confirm that TPM was not only safe but very effective for the control of recurrent epileptic seizures or SE in patients with serious medical co-morbidities. TPM may be considered as another treatment option when conventional protocols are ineffective.

Newer anticonvulsant medications in pediatric neurology

OPINION STATEMENT

Antiepileptic drugs (AEDs) are the mainstay of treatment for recurrent seizures. Uncontrolled seizures may cause medical, developmental, and psychological disturbances. The medical practitioner should thus strive to eliminate or minimize seizures. Treatment advances in epilepsy include 1) identification of the basic mechanisms of epilepsy and action of AEDs, 2) the introduction of new AEDs, and 3) the use of neurostimulation, including vagus nerve stimulation. Treatment with AEDs involves balancing each AED's efficacy against its side effects. In some patients, effective AEDs must be discontinued because of intolerable side effects. Although all AEDs have a proven efficacy, the choice of AEDs should be based on better efficacy for individual seizure types or epilepsy syndromes. Side effects also differ from drug to drug and must be taken into account. This article focuses on studies and expert opinion consensus to guide the choice of AEDs.

Long-term open-label study of adjunctive topiramate in infants with refractory partial-onset seizures

Data from 2 studies (phase 1 and phase 3) in infants <2 years old (N = 284; mean [SD] age, 12[6.3] months) with refractory partial-onset seizures were pooled to assess the long-term safety up to 1 year (primary objective) and tolerability of adjunctive topiramate treatment (mean treatment duration = 282 days). Monthly seizure rate summaries were also assessed. During the open-label extensions of these studies, study medication was first titrated to a dose of 25 mg/kg/d with subsequent uptitration to the maximum dosage tolerated, or seizure freedom, or a maximum of 60 mg/kg/d, whichever occurred first. The most common treatment-emergent adverse events (≥30%) were fever (52%), respiratory tract infections (51%), anorexia (35%), and acidosis (31%). Mean (SD) changes from pretreatment baseline to endpoint in Z scores for growth parameters were as follows: -0.82 (1.19) (body weight), -0.45 (1.60) (body length), and -0.36 (1.02) (head circumference).Tolerability in infants was consistent with previous studies.

Efficacy of Topiramate as an add-on drug in seizures in Indian children--an observational study

OBJECTIVE

To assess the efficacy of Topiramate as an add-on drug in the treatment of seizures in children of age group 0-12 years.

METHODS

Fifty children of age 0-12 years with seizures viz. partial seizures with or without secondary generalization, myoclonic jerks, infantile spasms, generalized tonic-clonic seizures, absence or mixed seizures were chosen from the out-patient department. Topiramate was added in small doses to conventional antiepileptics, and increased till the most effective/best-tolerated dose was reached. A Seizure Improvement Scale (SIS) was used. Outcome variables included seizure type, frequency, severity, SIS based on starting dose and the dose at the end of 6th month, EEG pattern, number of concomitant drugs used and adverse effects. Data was collected in monthly follow up visits for next 6 months (0-6 month study period). Details of seizures and medication availed by the study population during the 6 month period prior to the start of study were retrieved from available case records; this was used as control (-6 to 0 month study period). Using each of the outcome variables, efficacy was ascertained by clinical and statistical comparison.

RESULTS

Myoclonic jerks, generalized tonic clonic seizures, partial seizures with secondary generalization and complex partial seizures constituted 75% of seizures. Z-test for proportion showed significant reduction (p < 0.05) in these seizure types. ANOVA test for repeated measures (f = 162.3, p < 0.01) showed a significant fall in seizure frequency in 0 to 6 month period (t = 2.0, df = 49, p < 0.05) in seizure frequency. 50%, 18%, 8% and 10% of children had 100%, >75%, >50% and <50% reduction in seizure frequency, respectively at the end of 6 months. Statistically significant reduction in severity (status epilepticus) was found. An association between starting dose and position in the SIS was noted (Chi-square test); the authors recommend a starting dose of 1-2 mg/kg/day. Similarly, significant association between dose at the end of 6(th) month and position in the SIS was found; the authors recommend an optimum maintenance dose of 2.5-7.5 mg/kg/day. Though not statistically significant, the percentage of subjects using one concomitant antiepileptic drug (monotherapy) increased from 23% to 34%; those using 2 and 3 drugs (polytherapy) decreased from 40% to 34% and 33% to 27%, respectively. EEG pattern reverted back to normal in eight children. Apart from minor adverse effects, none had serious systemic manifestations during the study period.

CONCLUSIONS

The authors support the efficacy and safety of Topiramate as an add-on drug in seizures in children.

Topiramate for the treatment of neonatal seizures

Therapeutic options for treating neonatal seizures, such as phenobarbital and phenytoin, lack efficacy and are potentially harmful to the developing brain. Topiramate appears effective as both an antiseizure and neuroprotective agent in animal models of newborn brain injury. Although topiramate is a common add-on agent in newborns, its use in this population has not yet been reported. We performed a retrospective cohort study of clinical topiramate use in newborns with acute symptomatic seizures that were refractory to standard agents. In four of six newborns, apparent reduction or no further seizures occurred. None of the children experienced side effects resulting in discontinuation of the drug, either during the hospital admission or after discharge. Prospective studies evaluating the safety and efficacy of topiramate for both seizures and neuroprotection will be important in determining whether it deserves widespread use in clinical practice.

The safety and tolerability of newer antiepileptic drugs in children and adolescents

The newer antiepileptic drugs (AEDs) provide more therapeutic options and overall improved safety and tolerability for patients. To provide the best care, physicians must be familiar with the latest tolerability and safety data. This is particularly true in children, given there are relatively fewer studies examining the effects of AEDs in children compared with adults. Since we now have significant paediatric literature on each of these agents, we provide a comprehensive and current literature review of the newer AEDs, focusing on safety and tolerability data in children and adolescents. Because the safety profiles in children differ from those in adults, familiarity with this literature is important for child neurologists and other paediatric caregivers. We have organized the data by organ system for each AED for easier reference.

Randomized trial of adjunctive topiramate therapy in infants with refractory partial seizures

OBJECTIVE

To evaluate the efficacy and safety of adjunctive topiramate (sprinkle capsules or oral liquid) in reducing daily rates of partial-onset seizures (POS) in infants with refractory POS.

METHODS

In this double-blind, placebo-controlled, parallel-group, international study, infants (n = 149) with clinical or EEG evidence of refractory POS were randomly allocated (1:1:1:1) to receive adjunctive topiramate 5, 15, or 25 mg/kg/d or placebo for 20 days. The primary variable was the median percentage reductions in daily POS rate from baseline to final assessment as recorded on a 48-hour video-EEG.

RESULTS

Of the 149 infants (mean age 12 months) included in the intent-to-treat analysis set, 130 completed the study. Median percentage reduction from baseline in daily POS rate was not significantly different (p = 0.97) between topiramate 25 mg/kg (20.4%) and placebo (13.1%). Lower doses were not formally tested, but nominal p values for comparisons with placebo were not significant (15-mg/kg/d dose: p = 0.97; 5-mg/kg/d dose: p = 0.91). Treatment-emergent fever, diarrhea, vomiting, anorexia, weight decrease, somnolence, and viral infection occurred more frequently (> or = 10% difference) with topiramate than with placebo.

CONCLUSION

In infants aged 1-24 months, topiramate 5, 15, or 25 mg/kg/d was not effective as adjunctive treatment for refractory partial-onset seizures. No new safety concerns associated with topiramate use were noted.

CLASSIFICATION OF EVIDENCE

This interventional study provides Class I evidence that topiramate 5, 15, or 25 mg/kg/d compared with placebo does not significantly reduce seizure rates in infants aged 1 month to 2 years with refractory partial-onset seizures.

Topiramate and adrenocorticotropic hormone (ACTH) as initial treatment for infantile spasms

Historically, adrenocorticotropic hormone was used as a first-line treatment for infantile spasms; however, there has been increasing use of topiramate as initial therapy. Here, we report a retrospective study of adrenocorticotropic hormone (ACTH) and topiramate as initial treatment for infantile spasms. The neurology patient database at the Children's Hospital of Philadelphia was searched using the International Classification of Diseases, Ninth Revision code for infantile spasms, and 50 patients were randomly chosen for chart review. We identified 31 patients receiving either adrenocorticotropic hormone or topiramate monotherapy (adrenocorticotropic hormone n = 12, topiramate n = 19) as a first-line treatment for infantile spasms. A total of 26 patients were symptomatic and 5 cryptogenic. Six patients treated with adrenocorticotropic hormone had resolution of clinical spasms and hypsarrhythmia within a month, but 3 relapsed. Of the 19 patients treated with topiramate, 4 patients eventually, though over a period of 0, 1, 8, or 69 months, had resolution of spasms and hypsarrhythmia.

Use of second-generation antiepileptic drugs in the pediatric population

Epilepsy is common in the pediatric population. Nine second-generation antiepileptic drugs have been approved in the US for use in epilepsy over the past 15 years: felbamate, gabapentin, lamotrigine, topiramate, tiagabine, levetiracetam, oxcarbazepine, zonisamide, and pregabalin. Their use in pediatric patients is fairly widespread, despite most of these agents not having US FDA indications for use. Felbamate and gabapentin were the first two second-generation antiepileptic drugs to be approved in the US. Felbamate use has been limited because of the occurrence of hepatotoxicity and aplastic anemia. Although gabapentin is a fairly well tolerated antiepileptic drug, its use has also been limited as a result of inconsistent efficacy and concern about seizure exacerbation. Lamotrigine and topiramate are broad-spectrum antiepileptic drugs with efficacy in a wide variety of seizure types. Both agents have some tolerability concerns: rash with lamotrigine and neuropsychiatric events with topiramate. There are very little data on tiagabine use in children, but this agent appears to be effective and to have a good tolerability profile. Levetiracetam is a second-generation antiepileptic agent that is available intravenously. Considering its good efficacy, fast onset of action, and low incidence of serious adverse effects, its use in the acute setting could potentially increase. Oxcarbazepine and zonisamide have been relatively well studied in pediatric seizure patients, including use as monotherapy. Both agents have demonstrated good efficacy and tolerability for patients as young as 1 month old. Vigabatrin and rufinamide are currently not available in the US, but have been shown to have some success in other countries. Pregabalin is the newest antiepileptic agent, but lacks pediatric data currently.

Neonatal seizures: dilemmas in workup and management

There is a pressing need for consistent, evidence-based guidelines in the management of neonatal seizures by pediatric neurologists and neonatologists. Israeli pediatric neurologists and neonatologists completed a 20-item, self-administered questionnaire on choices of antiepileptic drugs, treatment of intractable neonatal seizures (unremitting seizures after 3 medications), treatment duration, and recommended workup. The responding 36/55 (65%) neurologists and 66/112 (59%) neonatologists made similar antiepileptic drug choices (phenobarbital as first line, phenytoin as second line, and benzodiazepines as third line). Antiepileptic treatment duration was similar for both groups, but varied considerably within them (range, 1-52 weeks). Neurologists tended to recommend longer treatment for seizures secondary to asphyxia or hemorrhage. Neurologists and neonatologists recommended different antiepileptic drugs for intractable neonatal seizures: valproic acid and topiramate by neurologists, vs lidocaine and benzodiazepines by neonatologists (P = 0.0023). Fewer neurologists recommended continuous electroencephalography monitoring after asphyxia than neonatologists (40% vs 70.5%, P = 0.013). These responses reflect both similarities and inconsistencies of the two groups in diagnosing and treating neonatal seizures. Our findings call for controlled clinical trials to establish protocols for (1) diagnosing neonatal seizures, (2) studying the efficacy and safety of new-generation antiepileptic drugs, and (3) determining optimal duration of drug administration.

Evaluation of open-label topiramate as primary or adjunctive therapy in infantile spasms

OBJECTIVE

A multicenter open-label clinical trial was conducted to evaluate the clinical usefulness of topiramate (TPM) as primary or adjunctive therapy for infantile spasms in the postmarketing period in China.

METHODS

Thirty-four centers participated in the trial. Patients included in the study had 1 or more seizures per day before treatment. One hundred twenty (22.1%) very young patients with an age younger than 6 month and 64.2% of patients were younger than 1 year at start of treatment. All patients received a starting dose of 0.5 to 1 mg kg d TPM twice daily. The dosage was increased by 0.5 to 1 mg kg d every 5 to 7 days up to 3 to 5 mg kg d. The resulting range of the total TPM dosage was 25 to 200 mg d (3.57-20 mg kg d), with a median value of 73.9 mg d. Seizure outcomes were measured by intention-to-treat analysis. Patients were seen by a neurologist, and their data were evaluated at the day of inclusion and after 4, 8, 12, 16, and 20 weeks (from visit 1 to visit 5) of treatment.

RESULTS

Five hundred forty-four patients entered the study. After 20 weeks of TPM treatment, 239 patients (43.9%) were seizure-free. A higher proportion of patients in the monotherapy group than in the add-on therapy group showed a seizure rate reduction. An increase in seizure frequency was observed in 8 patients (1.5%) during the 20-week treatment period. Nineteen patients were withdrawn before completing the study, and in 46 cases, some data of the structured data files and questionnaires were missing. No efficacy of TPM treatment was recorded in these cases. Adverse effects occurred in 211 patients (38.8%). Most frequent side effects were anorexia and somnolence.

CONCLUSIONS

Topiramate proved to be an effective and safe monotherapy and add-on therapy in patients with infantile spasms younger than 1 year.

Topiramate in children with west syndrome: a retrospective multicenter evaluation of 100 patients

The aim of this study is to investigate the efficacy and tolerability of topiramate in a large number of children with West syndrome. The authors performed a retrospective, questionnaire-based data collection in specialized epilepsy units in Germany. Patients with West syndrome and hypsarrhythmia could be included if topiramate treatment had started at an age of < or =3 years. Data of 100 patients were evaluated. Nearly all patients were severely affected and had been treated with multiple antiepileptic drugs with insufficient effect. Topiramate was introduced at a median age of 11.9 months. The median starting dosage was 1.6 mg/kg body weight per day, increased to a median maximum dosage of 12.0 mg/kg. Sixty-one patients received between 1 and 3 antiepileptic drugs in addition to topiramate. The median daily dose considered by the attending physicians to be most effective regarding seizure reduction was 10 mg/kg. A significant reduction in the number of seizures per week was achieved. A total of 17.5% of patients became free of seizures, and in 47%, the seizure frequency decreased by at least 50%. Hypsarrhythmia or status-like electroencephalography patterns remitted in 18 of 83 cases. Side effects were reported in 25% of children and included mostly sedation, loss of appetite, weight loss, and metabolic acidosis. These side effects were statistically related to the number of additional antiepileptic drugs but not to the topiramate dosage. In 17% of patients, topiramate treatment was discontinued because of side effects and in a further 4% because of worsening of seizures. In 44% of patients, treatment was continued for more than 3 months. In conclusion, the data suggest that topiramate is a useful drug in treating West syndrome. However, because of the inherent limitations of the retrospective study design, future prospective controlled studies should be performed.

Prospective Study of First-choice Topiramate Therapy in Newly Diagnosed Infantile Spasms

OBJECTIVE

This was a prospective open study to establish the efficacy, tolerability, and problems associated with the use of topiramate as first-choice drug in children with infantile spasms.

METHODS

Open-label follow-up study, ranging from 24 to 36 months, of the cases of 54 patients with infantile spasms treated initially with topiramate as first-choice drug.

RESULTS

Thirty-one patients (57.4%) were seizure free for more than 24 months; 9 patients were treated with topiramate alone and 22 patients with topiramate plus nitrazepam and/or valproate. In 44 cases (81.4%), the reduction of seizure frequency from baseline was greater than 30%, whereas in 10 cases (18.6%), there was poor or no response. The average dosage applied was 5.2 mg/kg per day (maximum dosage, 26 mg/kg per day; minimum dosage, 1.56 mg/kg per day). Adverse events occurred in 14 patients (26%). They included poor appetite leading to anorexia, absence of sweating, and sleeplessness.

CONCLUSIONS

Topiramate proves to be an effective and safe first-choice drug not only as adjunctive but also as monotherapy of infantile spasms in children younger than 2 years.

Topiramate monotherapy in infantile spasm

Infantile spasm is an age-related refractory epilepsy. Topiramate is a new anticonvulsant with multiple mechanisms of action, and it may be effective for treating pediatric epilepsies. To evaluate the efficacy and tolerability of first-line topiramate treatment for infantile spasm, 20 patients received topiramate monotherapy during this study. They were treated with an initial dose of 1mg/kg/day, with a progressive titration of 1 mg/kg a week until their spasms were controlled and a maximum dose of 12 mg/kg/day was achieved. The evaluation of the treatment efficacy was based on the spasm frequency data that was obtained by the scalp and video-EEG, and by the parental count of spasm. Thirty percent of the subjects became spasm-free during the study. Six of 20 subjects (30%) had cessation of spasm and disappearance of hypsarrhythmia as seen via the video EEG; four (50%) of eight idiopathic patients had a response, whereas two (17%) of 12 patients with symptomatic infantile spasm responded. Seventy of the patients, including the spasm-free patients, had a reduction in their seizure frequency of more than 50%, and 10% of the patients had a reduction in their seizure frequency of less than 50%. The clusters of spasm frequency decreased from 10.6 +/- 8.5 to 3.5 +/- 1.4 clusters/day. Topiramate is effective and tolerated in those patients suffering from infantile spasm. Our results suggest that this drug should be considered as a new first-line drug for treating infantile spasm.

Topiramate Loading for Refractory Status Epilepticus in Children

PURPOSE

To describe three cases of refractory status epilepticus (RSE) in children responsive to topiramate (TPM).

METHODS

Patients with SE refractory to therapeutic doses of at least two antiepileptic medications were given TPM, 10 mg/kg/d, for 2 consecutive days, followed by maintenance doses of 5 mg/kg/d.

RESULTS

This protocol has been used in three cases of RSE at our institution. In each case, SE was aborted within 21 h of the initial dose of TPM. Two patients avoided pharmacologic coma, and one was rapidly weaned from continuous benzodiazepine infusion.

CONCLUSIONS

Our experience indicates that TPM loading can be effective in the treatment of RSE in children.

Topiramate for the treatment of infantile spasms

Topiramate is a new antiepileptic drug with a broad spectrum of efficacy. Reports on the use of topiramate for treatment of infantile spasms are limited. We prospectively followed 15 children with recently diagnosed infantile spasms treated with topiramate for efficacy and tolerability. Twelve patients had symptomatic infantile spasms, and two patients had cryptogenic infantile spasms. Topiramate was started at a dose of 3 mg/kg/day and titrated up to a dose of 27 mg/kg/day in 2 to 3 weeks. The primary efficacy measure was comparison of the seizure rate during the 2-week baseline with the median seizure rate during the first 2 months of treatment with topiramate. We also compared baseline electroencephalograms (EEGs) with post-treatment EEGs. The median seizure rate reduction during the first 2 months of treatment was 41% (P = .002). Three patients became spasm free (20%), five had > 50% reduction, and three had at least 25% reduction. Four patients did not respond. Three of 15 patients had clearing of hypsarrhythmia. Topiramate was generally well tolerated, with irritability being the most common side effect. Topiramate was efficacious and well tolerated; one patient discontinued the medication because of adverse effects. (J Child Neurol 2006;21:17-19).

The efficacy and side effects of topiramate on refractory epilepsy in infants and young children: A multi-center clinical trial

OBJECTIVES

This study has been conducted to assess the efficacy and safety of topiramate in refractory epilepsies in infants and young children.

METHODS

A prospective clinical trial was performed in three tertiary care hospitals, on 47 children aged 6-60 months with refractory epilepsy. Topiramate was added to at least two baseline anti-epileptic drugs. The efficacy was rated according to seizure type, frequency and duration.

RESULTS

Children with refractory epilepsy were classified according to their clinical, neuro-imaging, and neurophysiological profile into infantile spasms (IS) (9 cases, 19%), Lennox-Gastaut syndrome (LGS) (25 cases, 53%) and other epilepsies (13 cases, 28%). Children were also classified into cryptogenic and symptomatic epilepsy. Topiramate was introduced as add-on therapy in a daily dose of 1 mg/kg/day for 2 weeks, followed by increments of 1-3 mg/kg/day at 2-week intervals, up to a maximum of 10 mg/kg/day. After a minimum treatment period of 6 months, 28 (60%) of the children had a satisfactory response (completely seizure free, or more than a 50% seizure reduction). The remaining 19 children (40%) had an unsatisfactory response (50% or less reduction in seizure frequency, no change or increased seizure frequency). Topiramate appeared to be equally effective in infantile spasms, Lennox-Gastaut syndrome and children with other types of epilepsy, with no significant difference between those with a satisfactory and an unsatisfactory response (p=0.089). There was also no significant difference in response between patients with cryptogenic and symptomatic epilepsy (p=0.360). Mild to moderate adverse effects, mainly somnolence, anorexia and nervousness, were present in 25 (53%) of children. One of the children developed hypothyroidism.

CONCLUSION

Although the long term safety and possible adverse effects of topiramate have not been fully established in infants and young children, this study has shown that it is a useful option for children with frequent seizures unresponsive to standard anti-epileptic drugs.

Efficacy and tolerability of topiramate in children younger than 2 years old

To evaluate the efficacy and tolerability of topiramate in children with epilepsy younger than 2 years of age, we retrospectively reviewed the records of patients treated at our institution between 2001 and 2003. Thirteen children ages 5 to 23 months, five boys and eight girls, were identified. Seizure types were partial (five), generalized tonic-clonic (three), myoclonic (one), and infantile spasms (four). The mean age at seizure onset was 9.7 months. Topiramate was started at a mean age of 11.4 months (4-23 months). The number of antiepileptic drugs prior to topiramate therapy ranged from zero to four. One patient had been on the ketogenic diet. Topiramate was used as monotherapy in seven children and as polytherapy in six children. Mean follow-up was 14 months. The mean dose of topiramate was 8.8 mg/kg/day (2.5-18 mg/kg/day). The degree of seizure reduction was as follows: > 75% in five (38.5%) children, 50% to 75% in three (23%) children, and 0 to 25% in five (38.5%) children. Three of four (75%) patients with infantile spasms had a > 75% reduction in seizures. Adverse effects occurred in two children, including lethargy, hyperthermia, and anorexia. In children younger than 2 years of age, for whom the antiepileptic drug armamentarium is limited, topiramate appears to be an efficacious and safe therapeutic alternative for a variety of seizure types.

Efficacy and safety of topiramate in infants according to epilepsy syndromes

Studies of the efficacy of topiramate (TPM) in infants and young children are few. Here we report an open, prospective, and pragmatic study of effectiveness of TPM in terms of epilepsy syndromes, in children aged less than 2 years. The median follow-up period was 11 months. We enrolled 59 children in the study: 22 affected by localization-related epilepsy (LRE), 23 by generalized epilepsy, six by Dravet's syndrome, and eight with unclassifiable epilepsy. TPM was effective (responders showed a decrease of more than 50% in seizure frequency) in 47% of patients, including 13% who were seizure-free at the last visit. TPM was more effective in localization-related epilepsy (48% of responders) than in generalized epilepsy (32% of responders). In the latter group, 19 patients suffered from infantile spasms. Four of six patients with cryptogenic infantile spasms became seizure-free. Of the 13 patients with symptomatic infantile spasms, only one was seizure-free. Results were poor for patients with Dravet's syndrome. In general, TPM was well tolerated. The most frequently reported adverse effects were drowsiness, irritability, hyperthermia, and anorexia. The present study concludes that TPM is effective for a broad range of seizures in infants and young children and represents a valid therapeutic option in this population.

Pediatric refractory partial status epilepticus responsive to topiramate

Topiramate was safely administered to two young children with refractory partial status epilepticus via nasogastric tube in rapid titration up to a very high total daily dose. An excellent clinical response occurred in both cases. Reaching high daily doses of topiramate within days allowed for safe discontinuation of other antiepileptic drugs in both patients. Given the high efficacy of rapidly titrated topiramate in our patients, this medication may be useful in some cases of pediatric refractory partial status epilepticus. However, more clinical studies on this therapeutic approach are needed to establish the precise role of topiramate in status epilepticus in children.

Pharmacologic treatment of the catastrophic epilepsies

Treatment of the catastrophic epilepsies [infantile spasms (IS), Lennox-Gastaut syndrome (LGS), and progressive myoclonic epilepsy (PME)] remains a challenge to clinicians. For IS, adrenocorticotropic hormone has traditionally been the drug of choice in the United States but may be associated with serious side effects in some patients. Vigabatrin has shown promise in treating IS patients, particularly those with tuberous sclerosis. However, the drug is associated with visual field loss and is not commercially available in the United States. Newer antiepilepsy drugs (AEDs), such as zonisamide, topiramate (TPM), and lamotrigine (LTG), may be useful in patients with IS. Although LTG, TPM, and felbamate are approved in the United States for the treatment of LGS, the overall effectiveness of therapy in patients with LGS is poor. For PME, valproate is a first-line treatment. Zonisamide and levetiracetam also show promise. Supplementation with certain cofactors to correct deficiencies and increase mitochondrial function may be useful in some patients with PME, but response to such therapy is not well documented. Advances in our understanding of the etiologies, mechanisms, and genetics underlying the catastrophic epilepsies may facilitate more effective pharmacologic interventions.