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Go T. Effect of antiepileptic drug polytherapy on urinary pH in children and young adults. Childs Nerv Syst 2009; 25:237-40. [PMID: 18704446 DOI: 10.1007/s00381-008-0687-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2008] [Indexed: 10/21/2022]
Abstract
OBJECTS The relationship between antiepileptic drugs (AEDs) polytherapy and urinary pH was studied to demonstrate the effect and difference of AED polytherapy compared to monotherapy. MATERIALS AND METHODS A total of 271 urine samples from patients receiving AED polytherapy aged from 7 months to 35 years were enrolled. Two AEDs were co-administered to 215 patients, three AEDs to 45 patients, four AEDs to ten patients, and five AEDs to one patient. RESULTS The distribution of urinary pH shifted to the alkaline range with increasing numbers of co-administered AEDs (p < 0.0001). The distribution of urinary pH shifted to the alkaline side with AED polytherapy that included valproate (p < 0.05) or acetazolamide (p < 0.03). The distribution of urinary pH did not change with or without zonisamide, carbamazepine, phenobarbital, phenytoin, or clonazepam. CONCLUSIONS Urinary pH should be monitored in patients receiving AED polytherapy, particularly those receiving valproate, acetazolamide, or various AEDs in combination.
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Affiliation(s)
- Tohshin Go
- Department of Infants' Brain and Cognitive Development, Tokyo Women's Medical University, 8-1 Kawada-cho, Shinjuku-ku, Tokyo, 162-8666, Japan.
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Mazarati A, Shin D, Auvin S, Sankar R. Age-dependent effects of topiramate on the acquisition and the retention of rapid kindling. Epilepsia 2007; 48:765-73. [PMID: 17319916 PMCID: PMC2376752 DOI: 10.1111/j.1528-1167.2007.00987.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
PURPOSE To examine antiepileptogenic, disease modifying, and anticonvulsant effects of topiramate under conditions of rapid kindling at different stages of development. METHODS Afterdischarge threshold (ADT) and duration (ADD) were examined in 2-, 3-, and 5-week-old Wistar rats before and after administration of topiramate (200 mg/kg). Animals underwent a rapid kindling protocol (sixty 10-s trains, bipolar 20 Hz square wave pulses delivered every 5 min). The progression of behavioral and electrographic seizures, and responses to test stimulations 24 h after the protocol were compared between topiramate and vehicle-treated control rats. In addition, rats that were previously given vehicle only prior to kindling, were then given topiramate to examine the effect on established kindled seizures. RESULTS In 2-week-old animals, topiramate affected neither the baseline afterdischarge, nor the progression of kindled seizures. In 3-week-old rats, topiramate did not modify the baseline afterdischarge, but significantly delayed the occurrence of full motor seizures in response to repeated stimulations. Topiramate treatment of 5-week-old rats increased baseline ADT, shortened ADD, and delayed the progression of kindled seizures. Twenty-four h after the last kindling stimulation, animals of all ages exhibited a decreased ADT, an increase ADD, and developed behavioral seizures in response to threshold stimulation. Vehicle-treated kindled rats that were then given topiramate displayed significantly attenuated behavioral seizures induced by the threshold stimulation. CONCLUSIONS Topiramate exhibited age-dependent disease-modifying effects under conditions of rapid kindling, but failed to block epileptogenesis. Topiramate also inhibited kindled seizures with equal efficacy across the three ages.
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Affiliation(s)
- Andréy Mazarati
- Department of Pediatrics, David Geffen School of Medicine at UCLA
| | - Don Shin
- Department of Pediatrics, David Geffen School of Medicine at UCLA
| | - Stéphane Auvin
- Department of Pediatrics, David Geffen School of Medicine at UCLA
- EA 1046, School of Medicine, Lille, France
- Pediatric Neurology Department, Lille University Hospital, Lille, Cedex, France
| | - Raman Sankar
- Department of Pediatrics, David Geffen School of Medicine at UCLA
- Department of Neurology, David Geffen School of Medicine at UCLA
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Michelucci R, Passarelli D, Riguzzi P, Volpi L, Tassinari CA. The Preclinical and Therapeutic Activity of the Novel Anticonvulsant Topiramate. CNS DRUG REVIEWS 2006. [DOI: 10.1111/j.1527-3458.1998.tb00062.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Go T. Effect of antiepileptic drug monotherapy on urinary pH in children and young adults. Childs Nerv Syst 2006; 22:56-9. [PMID: 15909204 DOI: 10.1007/s00381-004-1130-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2004] [Indexed: 10/25/2022]
Abstract
OBJECTS Since alkaline urine is a risk factor for urolithiasis, the relationship between antiepileptic drugs and urinary pH was retrospectively studied in epilepsy patients treated with antiepileptic drug monotherapy for more than 1 month. METHODS A total of 913 urinary samples from antiepileptic drug-treated patients were compared with 780 age-matched control samples, and with 112 samples from epilepsy patients who had not been treated with antiepileptic drugs. The antiepileptic drugs administered were carbamazepine, valproate, phenobarbital, zonisamide, sulthiame, and phenytoin. CONCLUSIONS The proportion of the acid urine in the valproate-treated patients was lower than that in controls. The proportion of the alkaline urine in the valproate-treated patients was higher than that in controls. This effect was independent of age, sex, and the serum valproate concentration. There was no significant difference in urinary pH among the epilepsy patients treated with other antiepileptic drugs, the epilepsy patients who had not been treated with antiepileptic drugs, and the controls.
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Affiliation(s)
- Tohshin Go
- Department of Infants' Brain and Cognitive Development, Tokyo Women's Medical University, Tokyo, 162-8666, Japan.
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Abstract
Urolithiasis is a rare side effect of antiepileptic drugs. To clarify the risk factors for urolithiasis induced by antiepileptic drugs, the effect of antiepileptic drug monotherapy on crystalluria was studied, and zonisamide or sulthiame therapy and alkaline urine were demonstrated to be risk factors. In the next investigation, the effect of antiepileptic drug polytherapy on crystalluria was retrospectively studied in epilepsy patients treated for more than 1 month during the last 7 years. A total of 278 urine specimens from epilepsy patients aged between 7 months and 36 years were enrolled in this study. The mean age was 12.3 years. There were 109 samples from females and 169 from males. Antiepileptic drugs administered in this study were valproate (174 urinary samples), zonisamide (139), carbamazepine (138), phenobarbital (65), phenytoin (52), acetazolamide (17), clonazepam (15), sulthiame (6), ethosuximide (6), nitrazepam (4), and clobazam (4). Epilepsy patients treated with antiepileptic drug polytherapy were frequently found to have crystalluria in patients demonstrating alkaline urine and taking acetazolamide, zonisamide (particularly with high serum levels), or many antiepileptic drugs in combination. Regular urinalysis seems to be necessary in these patients, and the evaluation for urolithiasis should be performed if persistent crystalluria is demonstrated.
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Affiliation(s)
- Tohshin Go
- Department of Infants' Brain and Cognitive Development, Tokyo Women's Medical University, 8-1 Kawada-cho, Shinjuku-ku, Tokyo 162-8666, Japan
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7
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Abstract
Lennox-Gastaut syndrome is a severe childhood epileptic syndrome with encephalopathy and multiple seizure types, which are often intractable to treatment. Most of these children will ultimately become mentally retarded and dependent on others for their daily care. Antiepileptic drugs are the mainstay of treatment, however, no particular drug is entirely effective. Apart from the use of antiepileptic drugs, nonpharmacologic treatments are also considered (i.e., callosotomy, ketogenic diet, and vagus nerve stimulation), which have proven to be partially effective. We prospectively studied 14 children (11 months-8 years of age) with medication-resistant Lennox-Gastaut syndrome, being treated with nitrazepam (open-label compassionate protocol). We compared the 1-month baseline seizure frequency with the median seizure rate reduction during the first 12 months of treatment with nitrazepam. The median seizure rate reduction during the first 12 months of treatment with nitrazepam was 41% (P = 0.001), with more than 50% seizure reduction in 60% of patients. Two patients became seizure free, five patients demonstrated at least 50% reduction in seizure rates, six patients had at least 25% seizure rate reduction, and one patient did not respond. No patient had any serious adverse effects. Side effects included sedation in six children (40%) and drooling in nine patients (60%).
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Affiliation(s)
- Syed A Hosain
- Weill Medical College of Cornell University, New York, New York, USA
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Hershey AD, Powers SW, Vockell ALB, LeCates S, Kabbouche M. Effectiveness of topiramate in the prevention of childhood headaches. Headache 2002; 42:810-8. [PMID: 12390646 DOI: 10.1046/j.1526-4610.2002.02185.x] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Migraine is a significant problem for many children. Topiramate has been suggested to be effective for the prophylaxis of migraine in adults, but has not yet been examined in children. The drug has been demonstrated to be safe and effective for childhood seizure disorders. The objective of this study was to demonstrate the safety and efficacy of topiramate for the prevention of pediatric migraine. METHODS Children with frequent migraine were prescribed topiramate for headache prevention. Dosages, serum levels, and Serum Glutamic Oxalacetic Transaminase (SGOT) levels were monitored. Changes in frequency, severity, and duration of headaches were recorded and changes in headache-related disability using PedMIDAS also were measured. RESULTS Ninety-seven children were treated with topiramate, and 75 were reevaluated 88.7 +/- 35.7 days later, 41 were seen at a second follow-up, and 17 were seen at a third follow-up evaluation. The daily dose reached at second evaluation was 84.0 +/- 38.6 mg/day or 1.42 +/- 0.74 mg/kg/day. This corresponded to a mean serum level of 2.8 +/- 1.6 micro g/mL. The mean headache frequency was reduced from 16.5 +/- 10.0 to 11.6 +/- 10.2 days per month (P<0.001) with a further reduction to 9.4 +/- 8.4 days by the second follow-up (P<0.001). Severity and duration of headache also were reduced. Headache disability improved, with a reduction of Pediatric Migraine Disability Assessment score from 36.0 +/- 42.3 to 20.8 +/- 34.0 at the first follow-up (P<0.05), 19.1 +/- 22.0 at the second follow-up (P<0.005), and 10.9 +/- 16.9 at the third follow-up (P<0.001). Most patients tolerated topiramate well. The most common side effects reported were cognitive (12.5%), weight loss (5.6%), and sensory (2.8%). CONCLUSIONS Topiramate is potentially an effective prophylactic medication for children with frequent migraine.
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Affiliation(s)
- Andrew D Hershey
- Division of Neurology, University of Cincinnati, College of Medicine, Cincinnati, Ohio, 45229-3039, USA
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Von Seggern RL, Mannix LK, Adelman JU. Efficacy of topiramate in migraine prophylaxis: a retrospective chart analysis. Headache 2002; 42:804-9. [PMID: 12390645 DOI: 10.1046/j.1526-4610.2002.02184.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE Topiramate, a broad-spectrum anticonvulsant with multiple mechanisms of action, may be effective in preventing migraine headaches. We report the results of a retrospective chart review of patients treated with topiramate for prophylaxis of migraine. METHODS Patients with a diagnosis of migraine who had at least one follow-up visit after > or =4 weeks on topiramate were eligible; 69 patients (56 women and 13 men) aged 18 to 68 years met these criteria. Charts were reviewed for frequency of mild or moderate/severe headaches at the start of topiramate (baseline) and at all subsequent visits up to 24 weeks. RESULTS The 28-day frequency of moderate/severe migraines declined significantly from baseline to end of treatment (10.6 +/- 8.4 to 7.4 +/- 7.7, respectively; P = 0.0004), whereas that of mild headaches did not demonstrate a significant change (from 11.8 +/- 8.9 to 11.0 +/- 10.0). Among the 38 patients who had not responded previously to >or =9 preventive medications, the monthly frequency of moderate/severe (but not mild) headaches decreased significantly from baseline to end of treatment. Patients who previously had not responded to <9 prior medications experienced significant declines in both mild and moderate/severe headaches. The most common adverse events were paresthesias, drowsiness, diarrhea, decreased appetite, and weight loss. Twenty-seven patients discontinued topiramate therapy, 20 as a result of adverse events and 7 due to lack of response. CONCLUSION Topiramate may be effective in reducing the frequency of both mild and moderate/severe migraine headaches. In particular, topiramate may offer relief to patients with moderate/severe migraines who do not respond to other treatments.
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Glauser TA, Pellock JM, Bebin EM, Fountain NB, Ritter FJ, Jensen CM, Shields WD. Efficacy and safety of levetiracetam in children with partial seizures: an open-label trial. Epilepsia 2002; 43:518-24. [PMID: 12027913 DOI: 10.1046/j.1528-1157.2002.13101.x] [Citation(s) in RCA: 126] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To assess the efficacy and safety of levetiracetam (LEV) as adjunctive therapy in children with treatment-resistant partial-onset seizures. METHODS Children (aged 6-12 years) with treatment-resistant partial-onset seizures receiving one standard antiepileptic drug (AED) were eligible. After a 4-week baseline period, children received LEV in a 6-week titration phase (target dose, 40 mg/kg/day) followed by an 8-week evaluation phase. Seizure frequency during the evaluation period with individualized LEV doses (20-40 mg/kg/day) were compared with the 4-week baseline seizure frequency. Plasma concentrations of LEV and other AEDs were determined to evaluate potential drug interactions. RESULTS Twenty-four subjects enrolled and received LEV; 23 entered the evaluation phase, and 22 completed the evaluation phase. Compared with their baseline seizure frequency, 12 (52%) of 23 subjects entering the evaluation phase had their seizure frequency decrease by >50%. Two subjects remained seizure free during the entire evaluation period. LEV did not significantly affect plasma concentrations of any concomitant AED during this study, and no alteration of mean clinical laboratory values was observed. The most commonly reported adverse events were headache, infection, anorexia, and somnolence. CONCLUSIONS This open-label study of adjunctive LEV therapy (at 20-40 mg/kg/day) suggests that LEV is effective, safe, and well tolerated in children ages 6-12 years with treatment-resistant partial-onset seizures. A randomized, placebo-controlled, double-blind trial of LEV adjunctive therapy in children with treatment-resistant partial-onset seizures is needed and ongoing to confirm these open-label findings.
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Affiliation(s)
- Tracy A Glauser
- Department of Neurology, Children's Hospital Medical Center, Cincinnati, Ohio 45229, USA.
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Longin E, Teich M, Koelfen W, König S. Topiramate enhances the risk of valproate-associated side effects in three children. Epilepsia 2002; 43:451-4. [PMID: 11952778 DOI: 10.1046/j.1528-1157.2002.42401.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE We present three children with severe therapy-refractory epilepsy who tolerated valproate (VPA) well in various combinations with other antiepileptic drugs (AEDs) but developed typical VPA side effects in combination with topiramate (TPM). METHODS The clinical symptoms began with apathy in all three children; two of them also had hypothermia. Furthermore all children had elevated blood ammonia levels, one child in combination with increased liver transaminases and one with thrombocytopenia. RESULTS All children recovered completely after discontinuation of VPA or TPM. CONCLUSIONS TPM seems likely to enhance the risk of side effects usually attributed to VPA and not described in TPM monotherapy. Our case reports suggest that possible adverse effects of VPA should be given particular attention when VPA is combined with TPM.
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Affiliation(s)
- Elke Longin
- Children's Hospital, University of Mannheim, Theodor-Kutzer-Ufer, 68167 Mannheim, Germany.
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12
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Abstract
Oxcarbazepine is a new antiepileptic drug (AED) that has been registered in more than 50 countries worldwide since 1990 and recently received approval in the United States and the European Union. Oxcarbazepine is a keto analog of carbamazepine and has a more favorable pharmacokinetic profile. It is rapidly absorbed after oral administration and undergoes rapid and almost complete reductive metabolism to form the pharmacologically active 10-monohydroxy derivative. Oxcarbazepine exhibits linear pharmacokinetics, no autoinduction, and minimal interaction with other AEDs. Ten controlled trials demonstrated that oxcarbazepine is safe and efficacious in the treatment of partial seizures across a wide range of ages (children to adults), situations (recent onset to treatment-resistant epilepsy), and uses (monotherapy and adjunctive therapy). The most common treatment-emergent adverse events are related to the central nervous system. Treatment-emergent hyponatremia (defined as serum sodium level < 125 mEq/L) occurred in 3% of patients treated with oxcarbazepine in clinical trials. According to the efficacy and safety profile established in the controlled trials, oxcarbazepine represents an important new treatment option indicated for monotherapy and adjunctive therapy in adults with partial seizures and as adjunctive therapy in children aged 4 years or older with partial seizures. Although structurally similar to carbamazepine, significant differences exist in the pharmacokinetics, drug interaction potential, adverse-effect profile, and dosage and titration between these two agents, and they should be considered distinct therapeutic agents.
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Affiliation(s)
- T A Glauser
- Department of Neurology, Children's Comprehensive Epilepsy Program, Children's Hospital Medical Center, Cincinnati, Ohio 45229-3039, USA.
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Affiliation(s)
- J Gilman
- Neuroscience Program, Miami Children's Hospital, FL 33155, USA.
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Abstract
PURPOSE To report a case of felbamate (FBM) urolithiasis. METHODS Urographic imaging [sonography, abdominal computed tomography (CT), intravenous pyelogram, voiding cystourethrogram] and urologic procedures (cystoscopy with lithotripsy, ureteral stent) to define and capture the stones. Stone identification was by infrared spectroscopy and gas chromatography/mass spectrometry. RESULTS A 15-year-old boy had painful hematuria, bilateral ureteral obstruction, and urinary retention. Kidney, bladder, and ureteral stones were found, and ureteral stent placement was required to relieve obstruction. The stone material was identified as FBM by chemical analysis. Stone formation ceased with discontinuation of FBM. CONCLUSIONS FBM urolithiasis can occur, and possible contributory factors include high felbamate dosage, drug polypharmacy, and risk factors for forming stones of other types. FBM urolithiasis may be heralded by crystalluria.
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Affiliation(s)
- S P Sparagana
- Division of Child Neurology, Texas Scottish Rite Hospital for Children, Dallas, USA.
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Montenegro MA, Guerreiro MM, Scotoni AE, Guerreiro CA. Predisposition to metabolic acidosis induced by topiramate. ARQUIVOS DE NEURO-PSIQUIATRIA 2000; 58:1021-4. [PMID: 11105067 DOI: 10.1590/s0004-282x2000000600007] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
RATIONALE Metabolic acidosis induced by topiramate is a well documented but infrequent adverse event. The objective was to demonstrate the lowering of carbon dioxide serum levels, which is usually asymptomatic but may facilitate the occurrence of metabolic acidosis in patients using topiramate. METHODS We evaluated, prospectively, the carbon dioxide serum levels of 18 patients seen at the epilepsy clinic of our university hospital, before and 3 months after introducing topiramate. RESULTS Five patients were female and 13 were male, age ranging from 2 to 16 years old (mean=9. 3). Carbon dioxide mean serum levels were 25 and 21.2 mmol/L (normal = 22 to 30), before and 3 months after introducing topiramate, respectively. Dose ranged from 2.08 to 11.76 mg/kg/day (mean=6. 7mg/kg/day). Adverse events were anorexia, nausea and somnolence. CONCLUSION We conclude that the lowering of carbon dioxide serum levels induced by topiramate is mostly asymptomatic, but may facilitate the occurrence of metabolic acidosis. Since patients in use of topiramate have refractory epilepsy, they may need epilepsy surgery, and must be carefully monitored for the risk of metabolic acidosis during surgery.
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Affiliation(s)
- M A Montenegro
- Departamento de Neurologia, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, SP, Brazil
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Nieto-Barrera M, Candau R, Nieto-Jimenez M, Correa A, del Portal LR. Topiramate in the treatment of severe myoclonic epilepsy in infancy. Seizure 2000; 9:590-4. [PMID: 11162758 DOI: 10.1053/seiz.2000.0466] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The aim of this study was to assess the effectiveness of topiramate (TPM) as an add-on regimen in reducing seizure rate in a population sample of patients diagnosed with severe myoclonic epilepsy in infancy (SME). Eighteen patients were evaluated. The mean observation time was 10.5 months (range, 6-18 months). Seizure frequency and type were recorded. Topiramate was administered as an add-on regimen at a starting dose of 1 mg kg(-1)and titrated to a maximum of 6-8 mg per kg per day. Different escalation rates were used, mainly weekly or fortnightly increments of dose. Three patients (16.6%) became seizure free, and 10 (55.6%) had a >50% reduction in seizure frequency: six of them (22.2%) achieved a reduction greater than 75%. Side-effects were observed in nine patients, eight with a weekly titration schedule and one with a fortnightly schedule. TPM is effective as adjunctive therapy for SME. Side-effects were mild and transient, generally related to rapid dosage titration.
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Affiliation(s)
- M Nieto-Barrera
- Paediatric Neurology Unit, Hospital Infantil Universitario Virgen del Rocio, Sevilla, Spain
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17
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Abstract
Because the efficacies of antiepileptic drugs (AEDs) are often equivalent, selection of an AED is often determined by adverse effects. Differences in methods for labeling adverse effects and in the adverse effect terms themselves, variations in the populations studied, and inconsistent classifications of adverse effects make it difficult to know how to use information on adverse effects to choose an AED. Effort is underway to develop more extensive and internationally acceptable descriptive terms for adverse effects. Comparison of adverse effects in patients taking AEDs with adverse events in control groups is helpful; however, data from controlled studies are often lacking for most AEDs. Because of these limitations, the clinician must adopt a preventative and early detection approach based on some general principles. This review outlines factors to consider for avoiding and detecting AED adverse effects. The occurrence of weight change with AEDs is reviewed extensively, serving to illustrate how the principle factors can be used to avoid and manage adverse effects and where there is need for better studies of the short- and long-term adverse effects of AEDs.
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Affiliation(s)
- R S Greenwood
- Department of Neurology, University of North Carolina School of Medicine, Chapel Hill 27599, USA
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Benedetti MS. Enzyme induction and inhibition by new antiepileptic drugs: a review of human studies. Fundam Clin Pharmacol 2000; 14:301-19. [PMID: 11030437 DOI: 10.1111/j.1472-8206.2000.tb00411.x] [Citation(s) in RCA: 92] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The aim of this paper is to review a number of new antiepileptic agents (i.e. felbamate, gabapentin, lamotrigine, levetiracetam, oxcarbazepine, tiagabine, topiramate, vigabatrin and zonisamide) for their inducing and/or inhibitory properties in humans, mainly considering the interactions where they are involved as the cause rather than the object of such interactions. Two aspects have been particularly taken into account: the changes or absence of changes in plasma/serum concentrations of concomitant drugs and the direct or indirect evidence of induction, inhibition or lack of effect on the six major human hepatic CYP isozymes (CYP1A2, CYP2C9, CYP2C19, CYP2D6, CYP2E1 and CYP3A4), as well as on other CYP isozymes or enzyme systems. Felbamate clearly affects the pharmacokinetics of a number of drugs, generally increasing but also decreasing their concentrations. It induces enzymes such as CYP3A4 and inhibits enzymes such as CYP2C19 and those of the beta-oxidation pathway. Topiramate is not devoid of potential interaction properties: it decreases the plasma concentrations of ethinylestradiol, induces CYP3A4 and inhibits CYP2C19. For oxcarbazepine, no inhibitory, only inductive effects have been observed thus far. Felbamate. topiramate and oxcarbazepine may induce the metabolism of steroidal oral contraceptives. In this respect, tiagabine has been studied at a rather low dose. Pharmacodynamic or pharmacokinetic interaction seems to exist between lamotrigine and carbamazepine. Lamotrigine appears to be a weak inducer of UGTs, whereas induction of CYP3A4 seems improbable as the compound does not change the concentrations of oral contraceptives or the urinary excretion of 6beta-hydroxycortisol. Zonisamide has very peculiar pharmacokinetics and an extensive metabolism. Additional information on its enzyme inducing or inhibiting properties would be necessary, as data so far collected on its effect on the pharmacokinetics of other drugs are conflicting. Gabapentin, vigabatrin and in particular levetiracetam appear to be devoid of significant enzyme inducing or inhibiting properties.
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Tang PH, Miles MV, Glauser TA, Coletta L, Doughman N, Doose D, Frey M, DeGrauw A. An improved gas chromatography assay for topiramate monitoring in pediatric patients. Ther Drug Monit 2000; 22:195-201. [PMID: 10774633 DOI: 10.1097/00007691-200004000-00010] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
An improved micromethod involving capillary gas chromatographic assay with liquid-liquid extraction and nitrogen phosphorus detection (GC/NPD) was developed and validated for the determination of topiramate (TPM) in human body fluids. The galactopyranose analog of TPM was used as the internal standard. Capillary gas chromatographic conditions yielded typical retention times of 6.8 min for TPM and 7.2 min for the internal standard. Calibrations were linear between 1.0 and 32 microg/mL. Between-day precision (n = 17) for three serum controls (3.0, 10, and 24.5 microg/mL) resulted in coefficients of variation of 6.9%, 7.3%, and 4.9%, respectively. The limit of detection was 0.42 microg/mL. There was an excellent linear correlation between the fluorescence-polarization immunoassay (FPIA) and GC/NPD determinations of 56 patient specimens (r2 = 0.981). Chromatograms showed no interfering peaks with the respective blank human samples or from many commonly prescribed drugs. Because of improved specificity and decreased sample volume requirements, this micromethod should be particularly useful for monitoring TPM therapy in pediatric patients, for patients with impaired renal function, and for research studies.
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Affiliation(s)
- P H Tang
- Division of Pediatric Neurology, The Children's Hospital Medical Center, Cincinnati, Ohio 45229-3039, USA
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De Sarro G, Gratteri S, Bonacci F, Musumeci SA, Elia M, De Sarro A. Topiramate potentiates the antiseizure activity of some anticonvulsants in DBA/2 mice. Eur J Pharmacol 2000; 388:163-70. [PMID: 10666508 DOI: 10.1016/s0014-2999(99)00779-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Topiramate (1-50 mg/kg, intraperitoneally (i.p.)) was able to antagonize audiogenic seizures in DBA/2 mice in a dose-dependent manner. Topiramate at dose of 2.5 mg/kg i.p., which per se did not significantly affect the occurrence of audiogenic seizures in DBA/2 mice, potentiated the anticonvulsant activity of carbamazepine, diazepam, felbamate, lamotrigine, phenytoin, phenobarbital and valproate against sound-induced seizures in DBA/2 mice. The degree of potentiation induced by topiramate was greatest for diazepam, phenobarbital and valproate, less for lamotrigine and phenytoin and not significant for carbamazepine and felbamate. The increase in anticonvulsant activity was associated with a comparable increase in motor impairment. However, the therapeutic index of the combination of all drugs+topiramate was more favourable than that of antiepileptics+ saline, with the exception of carbamazepine or felbamate+topiramate. Since topiramate did not significantly influence the total and free plasma levels of the anticonvulsant drugs studied, we suggest that pharmacokinetic interactions, in terms of total or free plasma levels, are not probable. However, the possibility that topiramate can modify the clearance from the brain of the anticonvulsant drugs studied cannot be excluded. In addition, topiramate did not significantly affect the hypothermic effects of the anticonvulsants tested. In conclusion, topiramate showed an additive effect when administered in combination with some classical anticonvulsants, most notably diazepam, phenobarbital, lamotrigine, phenytoin and valproate.
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Affiliation(s)
- G De Sarro
- Chair of Pharmacology, Department of Experimental and Clinical Medicine, Faculty of Medicine and Surgery, University of Catanzaro, Policlinico Mater Domini, Via T. Campanella, 88100, Catanzaro, Italy.
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Abstract
Six studies are cited to demonstrate that topiramate is effective as adjunctive therapy for refractory partial-onset seizures in adults. Subsequent studies indicate that topiramate is also effective as monotherapy in adults and as adjunctive therapy for partial-onset seizures in children, tonic-clonic seizures of nonfocal origin in children and adults, and drop attacks in Lennox-Gastaut syndrome. Adverse effects for adults and children included dizziness, fatigue, ataxia, confusion, somnolence, nephrolithiasis, paresthesia, and weight loss. More adverse effects were observed at higher doses. Topiramate exhibits rapid absorption, long duration of action, and minimal interaction with other antiepileptic drugs.
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Affiliation(s)
- T A Glauser
- Department of Neurology, Children's Hospital Medical Center, Cincinnati, Ohio 45229-3039, USA
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22
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Abstract
PURPOSE This study's goal was to provide preliminary data on the pharmacokinetics of topiramate (TPM) in a cohort of infants (younger than 4 years) participating in an open-label trial of TPM in refractory infantile spasms. METHODS The pharmacokinetics of TPM were assessed in infants receiving a stable TPM dose for >7 days during the extension phase of this trial. Blood samples were drawn just before and 0.5. 1, 1.5, 2, 4, 6, 8, and 12 h after the morning TPM dose. TPM plasma concentrations were determined by fluorescence polarization immunoassay. The noncompartmental analysis module of WinNonlin was used to calculate individual patient pharmacokinetics profiles. RESULTS Five infants (ages, 23.5-29.5 months) formed the study cohort. These infants had been given TPM for a median of 9 months (range, 6-11 months) and were currently receiving between 11 and 38.5 mg/kg/day TPM. One was receiving TPM monotherapy, whereas four were taking concomitant antiepileptic medications (AEDs; n = 2, enzyme-inducing agents; n = 2, non-enzyme-inducing drugs). TPM pharmacokinetics in infants appears to be linear. In this cohort, mean TPM plasma clearance (CL/F, 66.6+/-27.4 ml/h/kg) was slightly higher than that reported for children and adolescents and therefore substantially higher than that reported for adults. TPM CL/F was higher and the calculated half-life shorter in the infants receiving concomitant enzyme-inducing AEDs. CONCLUSIONS Based on this small cohort of patients, it appears that infants may require significantly larger TPM doses, based on weight, than children, adolescents, or adults. Titration to effect and not absolute TPM dose should guide therapy in this age group.
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Affiliation(s)
- T A Glauser
- Children's Comprehensive Epilepsy Program, Department of Neurology, Children's Hospital Medical Center, Cincinnati, Ohio 45229-3039, USA
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Abstract
PURPOSE West syndrome is a rare epileptic syndrome associated with infantile spasms, a specific abnormal electroencephalographic pattern (termed hypsarrhythmia), and mental retardation. Management of this disorder is difficult because current treatment regimens, including many anticonvulsants and hormones, are often ineffective. Topiramate (TPM) is a new antiepileptic drug that may be effective in pediatric epilepsies. We conducted a pilot study to test the effects of rapid TPM dosing in patients with refractory infantile spasms. METHODS Eleven children with refractory infantile spasms were given an initial dose of 25 mg TPM per day in addition to their current therapy. Dosage was increased by 25 mg every 2-3 days until spasms were controlled, the maximal tolerated dose was reached, or the maximal dose of 24 mg/kg/day was achieved. Efficacy was primarily assessed by video EEG and secondarily by parental count of spasm frequency. RESULTS Five (45%) subjects became spasm free during the study, with absence of infantile spasms and hypsarrhythmia (either classic or modified) proven by video EEG. Nine subjects, including the five spasm free, achieved a spasm reduction of > or =50%. Spasm frequency decreased from 25.6+/-19.3 to 6.9+/-5.9 spasms/day. Sixty-four percent of the subjects were able to achieve TPM monotherapy. CONCLUSIONS Results in this cohort of 11 patients with refractory disease show TPM to be a promising new agent for the treatment of infantile spasms.
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Affiliation(s)
- T A Glauser
- Comprehensive Epilepsy Program, Children's Hospital Medical Center, Cincinnati, Ohio 45229-3039, USA
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Abstract
Topiramate (TPM), a new antiepileptic medication, is efficacious as adjunctive therapy in adults with partial onset seizures. Its efficacy as adjunctive therapy in children was evaluated in two randomized double-blind placebo-controlled trials involving childhood epileptic encephalopathy (the Lennox-Gastaut syndrome) and partial onset seizures. In these studies, topiramate adjunctive therapy resulted in a significant reduction in drop attacks (tonic or atonic seizures) in patients with the Lennox Gastaut syndrome and a significant reduction in partial onset seizures in children with refractory partial epilepsy. In both trials, TPM's efficacy improved as the dose escalated from the double-blind phase to the open-label portion. The minimally effective topiramate dose for adjunctive therapy in children with refractory epilepsy appears to be 6 mg/kg/day. Topiramate was well tolerated with mild or moderate side effects, predominantly related to the central nervous system. Practical tips are provided that may increase the chance that topiramate will be effective and well tolerated. The most important advice is a "start low, go slow" approach. An initial TPM dose of 0.5-1 mg/kg/day followed by weekly increments of 0.5-1 mg/kg is usually well tolerated. Based on these studies, topiramate appears to be an important addition to our pediatric AED armamentarium.
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Affiliation(s)
- T A Glauser
- Department of Neurology, Children's Hospital Medical Center, Cincinnati, Ohio 45229-3039, USA
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Kamin M, Cazzaniga EK, Raina MK, Shank RP. The utility of the lh/lh mutant mouse as a animal model of human absence epilepsy. Epilepsia 1998; 39:232-3. [PMID: 9578004 DOI: 10.1111/j.1528-1157.1998.tb01362.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Ferrie CD, Livingston JH. The new anti-epileptic drugs: a review. Eur J Paediatr Neurol 1997; 1:139-47. [PMID: 10728210 DOI: 10.1016/s1090-3798(97)80050-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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