Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0036572 (seizures)
 80,221 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

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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PMID:Topiramate. 1053 Jun 97

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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PMID:Topiramate potentiates the antiseizure activity of some anticonvulsants in DBA/2 mice. 1066 8

Topiramate is a new anti-epileptic drug with proven efficacy against partial seizures in adults. A retrospective assessment of the use of topiramate in drug-resistant childhood epilepsy was undertaken. Thirty-four children (median age of 10 years; range 2-18 years) were treated for a median of 9 months (range 6-18 months). The starting dose was 0.25-2.0 mg/kg/day increasing to a maximum of 13 mg/kg/day. Generalized seizures occurred in 27 patients, partial seizures in 15 and infantile spasms in two. Epilepsies were localization-related in 15 patients and generalized in 18. One patient had severe myoclonic epilepsy in infancy. Two patients had Lennox-Gastaut syndrome, five (two currently and three previously) had West syndrome and one had epilepsy with myoclonic absences. Twenty patients had a substantial (> 50%) reduction in seizure frequency; two of whom became seizure-free. Two-patients had an increase in seizures. Efficacy was seen against simple and complex partial seizures, generalized tonic-clonic seizures (primarily generalized), atonic and tonic seizures, myoclonic seizures and infantile spasms. There was no response in the one patient with myoclonic absence seizures. Adverse effects were reported in nine patients; appetite suppression occurred in five patients, behaviour disturbances in three, somnolence in two and poor concentration in one patient. Topiramate is efficacious in a wide spectrum of childhood epilepsies and is well tolerated.
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PMID:Topiramate for drug-resistant epilepsies. 1070 Nov 2

Topiramate is a new antiepileptic drug that has now become available for prescription in Belgium. In vitro and in vivo preclinical studies have indicated that topiramate has several mechanisms of action that may contribute to its anticonvulsivant activity. A broad antiepileptic spectrum could be suspected that has been confirmed on a clinical basis. Topiramate has favorable pharmacokinetic properties: rapid absorption, long half-life and little interaction with other AED. Several meta-analysis have confirmed its efficacy, particularly as adjunctive therapy for partial onset seizures, refractory to other AED. It is actually reimbursed only for these patients but its indications will probably be widened in the future.
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PMID:[Pharmacy clinics. Medication of the month. Topiramate (Topamax)]. 1076 82

Topiramate is a recently released antiepileptic agent used in the treatment of patients with refractory seizure disorders. In addition to its antiepileptogenic activities, it results in inhibition of carbonic anhydrase isoenzymes II and IV, which are present in the central nervous system. A 15-year-old female who presented with hyperpnea and primary respiratory alkalosis is reported. Other possible etiologies of the central hyperventilation syndrome were excluded. The problem resolved within 24 hours after discontinuing topiramate.
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PMID:Central hyperventilation related to administration of topiramate. 1078 49

After a short historical review of the development of the pharmaceutical treatment of the epilepsies the author reviews some of the possible strategies to manage patients with the different types of epilepsies and epileptic syndromes using the classical drugs. A strategy used by most of the physicians uses Sodium Valproate as the first line drug for almost all patients. This may be replaced by other drugs according to their efficacy against the different types of seizures to be treated whenever VPA has not enough efficacy or isn t well tolerated. On the other hand epileptologists use the different drugs according to the different epilepsies and epileptic syndromes depending on the relative efficacy of each drug available and the possible side effects. He then describes succinctly the better-known new drugs and makes some comments on the coming drugs now in development. Finally he proceeds to include them in the strategies above described. Lamotrigine and possibly Topiramate are good candidates to replace VPA in the one drug strategy. Lamotrigine, Oxcarbamazepine and possibly Gabapentin may be used in the future as 1st line drugs in selected patients. Vigabatrin is already used as one of the better alternatives for West syndrome and Oxcarbamazepine has replaced Carbamazepine in countries where it s available to the public. Some drawbacks have been apparent with these drugs like the hepatic and haematological toxic effect of Felbamate or the apparently irreversible fields constriction provoked by Vigabatrin, which did limit their use.
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PMID:The new drugs and the strategies to manage epilepsy. 1082 13

A 3-year retrospective review was undertaken of the use of topiramate in 51 children aged 3-16 years with partial and generalized epilepsies who attended a tertiary referral epilepsy centre in a large children's hospital. The mean follow-up period was 19 months (range 6-33 months). Twenty-six children (51%) were still receiving topiramate at the time of their last review. Fifteen children (29%) showed a greater than 50% reduction in their seizure frequency and four children (8%) became seizure free, three on topiramate monotherapy. The drug appeared to be most effective in children with moderate learning difficulties with 75% showing an improvement in seizure control compared with 25% of children with normal educational functioning. Topiramate was withdrawn in 25 patients. The reasons for withdrawal included adverse effects in 20, lack of effect in three and worsening of seizures in two patients. Adverse side effects were reported in 57% of the 51 patients. The majority of the side effects were related to behavioural and cognitive difficulties, with less-common side effects including anorexia, weight loss and headaches.
Seizure 2000 Mar
PMID:Efficacy and tolerability of topiramate in childhood and adolescent epilepsy: a clinical experience. 1084 39

Topiramate is a novel antiepileptic drug, a fructopyranose derivative. In animal studies, topiramate suppresses maximal electroshock seizures, whereas it does not exert inhibitory effects on pentylenetetrazol-induced seizures. Since topiramate hardly affects the threshold of the seizure, topiramate has been believed to be a type of antiepileptic drug that blocks spread of seizures. Thus far, the mechanisms of its actions have been proven to include use-dependent inhibition of voltage-dependent Na+ channels in neurons, potentiation of GABA (gamma-amino-butyric acid)-induced Cl- influx, and inhibitory effects on inward currents by antagonizing kainate/alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptors. In clinical studies conducted overseas, topiramate has been demonstrated to be effective in the treatment of partial seizures etc. In 55 countries including UK and USA, topiramate has been already approved for the clinical use as a drug for partial seizures, while a phase III study has been planned in Japan, using patients with symptomatic localization-related epilepsies.
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PMID:[Target pharmacology of topiramate, a new antiepileptic drug]. 1087 16

A lack of systematic pharmacoepidemiological studies investigating adverse drug reactions (ADRs) to anticonvulsants makes it difficult to assess accurately the incidence of anticonvulsant-related ADRs. Most of the available information in this regard stems from clinical trial experience, case reports and postmarketing surveillance, sources that are not, by any means, structured to provide precise data on adverse event epidemiology. For various ethical, statistical and logistical reasons, the organisation of structured clinical trials that are likely to provide substantial data on ADRs is extremely difficult. This review concentrates on current literature concerning serious and life-threatening ADRs. As with the older anticonvulsants, the majority of ADRs to newer anticonvulsants are CNS-related, although there are several that are apparently unique to some of these new drugs. Gabapentin has been reported to cause aggravation of seizures, movement disorders and psychiatric disturbances. Felbamate should only be prescribed under close medical supervision because of aplastic anaemia and hepatotoxicity. Lamotrigine causes hypersensitivity reactions that range from simple morbilliform rashes to multi-organ failure. Psychiatric ADRs and deterioration of seizure control have also been reported with lamotrigine treatment. Oxcarbazepine has a safety profile similar to that of carbamazepine. Hyponatraemia associated with oxcarbazepine is also a problem; however, it is less likely to cause rash than carbamazepine. Nonconvulsive status epilepticus has been reported frequently with tiagabine, although there are insufficient data at present to identify risk factors for this ADR. Topiramate frequently causes cognitive ADRs and, in addition, also appears to cause word-finding difficulties, renal calculi and bodyweight loss. Vigabatrin has been reported to cause seizure aggravation, especially in myoclonic seizures. There have been rare reports of other neurological ADRs to vigabatrin, such as encephalopathy, aphasia and motor disturbances. Vigabatrin-induced visual field constriction is the latest and most worrying ADR. Many questions regarding the nature of this potentially serious ADR remain unanswered, as no prospective controlled study examining the phenomenon has been published. Rare cases of behavioural ADRs and IgA and IgG2 deficiency associated with the use of zonisamide have been reported. However, relatively few patients so far have been exposed to this drug, and therefore more postmarketing information is required. The relatively late establishment of aplastic anaemia and hepatic failure as potentially fatal ADRs of felbamate, and of visual field constriction with vigabatrin, should serve as ample reminders that ADRs can appear at any time.
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PMID:Adverse reactions to new anticonvulsant drugs. 1091 31

Topiramate (Topamax) has been registered since July 1998 and has market authorization for the Federal Republic of Germany as an additive drug for the treatment of patients (age 12 or older) suffering from intractable partial and secondarily generalized seizures. The anticonvulsant effect of topiramate is based on three mechanisms: (a) modulating the blocking of the Na channels activated by voltage, depending on status, (b) potentiation of GABAA-mediated inhibiting neurotransmission, and (c) inhibition of excitatory neurotransmission by blocking APMA glutamate receptors. Topiramate exhibits a substantial anticonvulsive effect on partial seizures both with and without secondary generalization. The median reduction in seizure frequency using topiramate as adjunct therapy was 44%. In 44% of patients, seizure frequency was reduced by more than 50%, and seizure reduction was more than 75% in nearly half of these (i.e., in 21% of all patients), while 5% of patients remained completely free of seizures. Adverse events most often caused central nervous disturbances. Weight loss, the development of renal calculi, and impairment of cognitive functions may occur. It is recommended to start therapy with topiramate at a daily dosage of 25 mg, increasing by 25 mg every week up to 200-400 mg/day but not exceeding 1000 mg/day.
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PMID:[Topiramate (Topamax). Pharmacological characteristics and current use in epilepsy treatment]. 1091 47


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