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)

The new antiepileptic drug zonisamide was evaluated in a European multicenter parallel-group double-blind trial as add-on treatment for 139 patients with refractory partial epilepsy. During treatment with zonisamide complex partial seizures decreased by 27.7% compared to placebo (P < 0.05) and the median rate dropped from 12/month to 7.1/month with no changes in the placebo group (P < 0.007). During the 12-week double-blind phase a 50% reduction of all seizures was recorded in 29.9% of the patients treated with zonisamide vs. 9.4% during placebo. Complete remission was observed during treatment with zonisamide in 6.2%. The plasma concentrations of the concomitant antiepileptic drugs did not change markedly when zonisamide was added. Adverse events, mostly fatigue, somnolence, dizziness and ataxia, occurred in 59.2% of the patients compared to 27.9% during placebo. Zonisamide was withdrawn in two patients due to adverse events. Kidney stones were not observed nor any relevant clinical chemistry or hematological changes. Zonisamide is an effective antiepileptic drug for add-on treatment of refractory partial epilepsy.
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PMID:Zonisamide for add-on treatment of refractory partial epilepsy: a European double-blind trial. 832 80

We investigated the effects of zonisamide, a new antiepileptic drug, on voltage-dependent T-type calcium current (ICa) in cultured neuroblastoma cells of human origin (NB-I). Zonisamide reduced T-type ICa in a concentration-dependent manner without evoking any change in its inactivation kinetics or voltage dependence of action. The mean percent reduction was 38.3 +/- 5.8% at 50 microM. Further, zonisamide shifted the inactivation curve approximately 20 mV negative compared to the control. These resting blocking actions suggest that zonisamide shifts the channel population toward the inactivation state, allowing fewer channels to open during membrane depolarization. The blockade of T-type calcium channels by zonisamide could suppress an important component of inward current that underlies epileptiform cellular bursting, thereby inhibiting the spread of seizure activity.
Seizure 1996 Jun
PMID:Mechanisms of T-type calcium channel blockade by zonisamide. 879 26

Zonisamide (1,2-benzisoxazole-3-methanesulfonamide, AD-810) is a broad spectrum antiepileptic drug which has been launched in Japan and South Korea. It lacks the ureide structure included in most of the existing antiepileptic drugs. Zonisamide was synthesized by the sulfonation and the successive amination of 1,2-benzisoxazole-3-acetic acid in a very poor yield. After several efforts to optimize the compound, zonisamide was selected based on the balance of the efficacy and safety. The yield was greatly improved by the development of new synthetic routes. Zonisamide suppressed maximal electroshock seizures in mice, rats, rabbits and dogs. Its therapeutic plasma concentration range between anticonvulsant and neurotoxic effects was much wider than that of the existing antiepileptic drugs. In electroencephalographic studies on animal models of epilepsy, zonisamide, like phenytoin and carbamazepine, restricted the spread or propagation of seizures and, like sodium valproate, it suppressed the epileptogenic focus activity. Zonisamide was effective in several kindling models. In clinical studies, zonisamide exerted the efficacy against partial seizures (simple, complex, secondarily generalized seizures) and some generalized seizures (tonic-clonic, tonic, atypical absence seizures) that were comparable to that of carbamazepine and sodium valproate, respectively. Zonisamide was also effective in monotherapy. The adverse effects related with zonisamide were mainly drowsiness, ataxia, loss of appetite and gastrointestinal symptoms. Serious adverse effects which may be life-threatening have not been reported.
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PMID:[Research and development of zonisamide, a new type of antiepileptic drug]. 883 Dec 58

This study was undertaken to evaluate the effect of ethanol intake on the anticonvulsive effects of Zonisamide (ZNS), a sulfonamide derivative. EL mice, which are highly susceptible to seizures, were given a 10% ethanol solution ad lib for 1-4 weeks. In mice given ethanol for 4 weeks, seizures were not suppressed by ZNS at a dose of 75 mg kg-1, i.p. Serum ZNS concentrations following ethanol consumption for 1-4 weeks were higher than in untreated mice; however, brain ZNS concentrations following ethanol consumption were lower than those in untreated mice. These results suggest that alcohol intake decreases the brain concentration of ZNS, but not the serum concentration.
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PMID:Alcohol intake decreases brain Zonisamide concentration in inbred EL mice. 908 Apr 13

Between 30% and 60% of patients with epilepsy have not achieved adequate control with current medications, and side effects are a significant problem. In the past 2 years, three drugs for epilepsy have been approved. At least six more drugs are in the final stages of development, and there is an active "pipeline." None of the new drugs are panceas, but many have special advantages and meet important specific needs. Felbamate, despite a high incidence of aplastic anemia and hepatic failure, remains useful because of its lack of sedative effects and high efficacy. Gabapentin is remarkable for its favorable side effect profile, lack of interactions, and straightforward kinetics. Lamotrigine is also nonsedating and may be especially useful in generalized epilepsies. Topiramate and vigabatrin are both highly effective, although each is associated with a variety of cognitive or psychiatric side effects that may limit utility. Oxcarbazepine shares the efficacy of carbamazepine, with fewer side effects or drug interactions. Zonisamide seems to be effective and cause mild side effects, although the risk for renal stones indicates a need for cautious use. Tiagabine, like gabapentin, is a mild drug with a favorable side effect profile. New forms of old drugs will make for easier administration; fosphenytoin will increase the safety of parenchymal phenytoin use. The best of the new drugs help, at most, 10% of previously uncontrolled patients to become seizure-free. The development of new drugs remains an important need.
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PMID:New drugs for persons with epilepsy. 940 64

Progressive myoclonic epilepsy (PME) syndromes are intractable to most antiepileptic drugs (AED). The course of these diseases, results in almost total dependency due to continuous myoclonias, repeated episodes of status epilepticus, ataxia and dementia. The need for new treatment strategies is therefore imperative. Zonisamide has previously been reported to be effective in two patients with PME. Case reports of seven patients (ages 19-42) with Unverricht-Lundborgs disease (ULD) and one Lafora Body Disease are presented. Zonisamide was given at doses of 100-600 mg/day for a period of 2 to 3 years. Concomitant AEDs were usually valproate and a benzodiazepine. Zonisamide dramatically reduced the amount of myoclonias and generalized seizures. In three of the cases, the initial dramatic effect on myoclonias wore off after 2-4 years of treatment but patients still experienced moderate efficacy for generalized tonic-clonic seizures. The dramatic reduction of stimulus sensitivity for light, touch and startle by zonisamide was sustained in all patients with ULD. Zonisamide may be a useful agent in the treatment of PME. Controlled clinical trials are warranted to further investigate the antiepileptic effects of this drug, in difficult to treat epileptic syndromes.
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PMID:Zonisamide for progressive myoclonus epilepsy: long-term observations in seven patients. 947 42

Based on small numbers of patients, it is possible to make the following suggestions rather than categorical statements. For myoclonic seizures and epilepsies which are not otherwise specified, valproate seems of proven efficacy. Ethosuximide may be a useful adjunct. The exact place of lamotrigine, which controls some myoclonia and makes them worse in other patients, requires further study. The findings are clearer when specific syndromes are considered. Valproate is the treatment of first choice for benign myoclonic epilepsy in infants, myoclonic astatic epilepsy, epilepsy with myoclonic absences, eyelid myoclonia with absences, juvenile myoclonic epilepsy and progressive myoclonus epilepsy. The addition of ethosuximide to valproate can be helpful to those with myoclonic absences, where this combination appears more beneficial than either valproate or ethosuximide alone and in eyelid myoclonia with absences. Lamotrigine can be effective therapy for juvenile myoclonic epilepsy and eyelid myoclonia with absences when used alone and, in conjunction with other antiepileptic drugs (AED) (usually valproate) for early myoclonic encephalopathy, myoclonic-astatic epilepsy and particularly, epilepsy with myoclonic absences. The myoclonia of infantile neuronal ceroid lipofuscinosis respond to lamotrigine. Severe myoclonic epilepsy of infants usually worsens with lamotrigine, but occasionally, children improve. Zonisamide added to clonazepam and valproate or a barbiturate, can reduce the cascade of myoclonia in progressive myoclonus epilepsies for at least 2 years, but relapse may occur thereafter.
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PMID:Myoclonus and epilepsy in childhood: a review of treatment with valproate, ethosuximide, lamotrigine and zonisamide. 947 47

A case of alternating hemiplegia of childhood is reported. Tonic fits and generalized tonic-clonic seizures developed during her infancy. Frequent twitching and apneic seizures appeared at 16 years of age. Zonisamide transiently suppressed the tonic, twitching and apneic seizures, as well as the facial and neck dystonia. Cranial computed tomography and magnetic resonance imaging revealed progressive vermian atrophy. Cerebellar dysfunction may play a role in the clinical features of some patients with alternating hemiplegia of childhood.
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PMID:A case of alternating hemiplegia of childhood with cerebellar atrophy. 1058 Aug 94

Zonisamide (1,2-benzisoxazole-3-methanesulfonamide) is a new antiepileptic drug developed in Japan. This compound is insoluble in water, and it is available in tablet and powder form. In experimental animals, this compound has been found to have a strong inhibitory effect on convulsions of cortical origin because it suppresses focal spiking and the spread of secondary generalized seizures. In humans, a series of double-blind, placebo-controlled studies revealed the efficacy of zonisamide for patients with refractory partial seizures and for selected patients with infantile spasms. Its antiepileptic mechanism of action remains unclear, but it is likely to involve blockade of both sodium and T-type calcium channels. Oral bioavailability of zonisamide is excellent in healthy human volunteers. Zonisamide is slowly absorbed and has a mean tmax of 5 to 6 hours. Almost 100% of it is absorbed; there is no difference in bioavailability between tablets and powder. Zonisamide concentrations are highest in erythrocytes and then in whole blood and plasma. It is approximately 40% to 60% bound to plasma proteins, primarily albumin. Its volume distribution is 0.9 to 1.4 L/kg. In adults, the elimination half-life is between 50 and 62 hours, and it takes as long as 2 weeks to reach steady state. The dose-serum level correlation is linear up to doses of 10 to 15 mg/kg per day, and the therapeutic range is 10 to 40 microg/ml. However, the relationship between serum zonisamide levels, clinical response, and adverse effects appears weak. Concurrent enzyme-inducing anticonvulsants such as phenytoin, carbamazepine, or barbiturates stimulate zonisamide metabolism and decrease serum zonisamide levels at steady state. Although zonisamide has been reported to increase the serum levels of phenytoin and carbamazepine in some patients, the interactions of zonisamide with other antiepileptic drugs seem to be of minor clinical relevance. A pilot study of zonisamide suppositories revealed that it is beneficial for patients with neurologic disorders in whom antiepileptic drugs cannot be administered by mouth.
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PMID:Clinical pharmacology and therapeutic drug monitoring of zonisamide. 985 71

Zonisamide is a new drug with broad-spectrum antiepileptic activity against partial as well as generalized seizures. The purpose of the present study was to compare the long-term efficacy of zonisamide in the treatment of epilepsy in children with intellectual disability (ID) with those with normal intelligence (NI). One hundred and thirty children (74 ID, 56 NI) were included in the study. Fifteen of the subjects were eliminated from the study because of adverse effects or aggravation of seizures. The remaining 115 children (66 ID, 49 NI) were followed up for more than one year. Twenty-eight children (6 ID, 22 NI) were in zonisamide monotherapy. The mean numbers of different antiepileptic drugs were 4.5 and 3 for the ID and NI groups, respectively. The overall improvement rates, defined as a >50% reduction in the number of seizures, were 41% (ID) and 67% (NI) (P<0.01). Side-effects were observed in 27% and 30% of subjects in the ID and NI groups, respectively. However, in the monotherapy group, side-effects were observed in 50% (ID) and in 27% (NI). In conclusion, the effectiveness of zonisamide was weaker in children with ID than those with NI. This is in agreement with the known phenomenon that epileptic children with ID are likely have more intractable seizures than those with NI.
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PMID:Long-term effects of zonisamide in the treatment of epilepsy in children with intellectual disability. 1003 Apr 36


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