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)

This study, a 4-month follow-up period of a 12-month treatment study by the present authors, was concerned with the permanent effects of treatment with diphenylhydantoin and phenobarbital in the alumina-gel monkey model. Whereas the 8 drug animals during withdrawal increased their seizure frequency, duration, and severity, those 4 animals having received 120 mg/kg/day DPH in weeks 6-12 had one-half the number of seizures of the 4 placebo monkeys in the follow-up period. The other 4 drug animals who had continued to receive 60 mg/kg/day DPH during those weeks had two to four times the number of seizures of the placebo group during posttreatment. (All drug monkeys received 80 mg/kg/day of DPH from weeks 13-52 and 6 mg/kg/day of phenobarbital throughout the 12-month treatment period). The results reaffirm the problems of drug withdrawal and the importance of altering seizure mechanisms with sufficiently high doses of efficacious anticonvulsants rather than merely treating epileptic manifestations at lower doses.
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PMID:Prophylaxis with diphenylhydantoin and phenobarbital in alumina-gel monkey model. II. Fourth-month follow-up period: seizure, EEG, blood and behavioral data. 81 92

The status of Papio papio as a model of clinical epilepsy has been reviewed. The anticonvulsant effects of single doses of various classic and experimental agents have been compared against seizures induced in the P. papio by intermittent light stimulation. Long-acting but not short-acting barbiturates have been shown fully to control seizures with minor sedative effects. Diphenylhydantoin (in chronic doses only) and trimethadione are often effective but not consistently so. Diazepam and clonazepam block seizures at very low doses both acutely and chronically. However, an initial dose well above threshold seems essential if anticonvulsant effects are to be maintained under chronic administration of these compounds. Carbamazepine and SC 13504 (1-benzhydryl-4(6 methyl-2-pyridylmethyleneimino)piperazine), as well as two nonstimulant analogues of amphetamine, were shown to be promising anticonvulsants in this model. A biphasic action of tetrahydrocannabinol, anticonvulsant at a few micrograms per kilogram but not at higher doses, was also demonstrated. Finally, the anticonvulsant action of intraventricular epinephrine and norepinephrine was reported.
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PMID:Measurement of anticonvulsant activity in the Papio papio model of epilepsy. 82 87

A case of phenytoin (DPH) encephalopathy with increasing seizures and EEG and mental changes is described. Despite adequate oral dosage of DPH (5 mg/kg/daily) the plasma level was very low (2.8 microgramg/ml). The encephalopathy was probably an idiosyncratic and not toxic or allergic reaction. In fact the concentration of free DPH was normal, the patient presented a retarded morbilliform rash during DPH treatment, the protidogram was normal, and an intradermic DPH injection had no local effect. The authors conclude that in a patient starting DPH treatment an unexpected increase in seizures, with EEG and mental changes occurring simultaneously, should alert the physician to the possible need for eliminating DPH from the therapeutic regimen, even if plasma concentrations are low.
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PMID:Phenytoin encephalopathy as probable idiosyncratic reaction: case report. 89 94

Progressive behavioral and electroencephalographic (EEG) changes were examined following daily administration of pentetrazol (PTZ) to rats. A dose (40 mg/kg/day i.p.) of PTZ which, on the first day, induced clonic convulsions with spike and wave complexes, over several days progressively increased its effect and finally induced 'violent convulsions' with EEG seizures of high frequency components. In rats showing these violent convulsions, the PTZ convulsive threshold was decreased and, even after a 4- to 10-month resting period, the violent convulsion was elicited with the same dose of PTZ. Trimethadione and phenobarbital in doses blocking clonic convulsion in normal rats, did not suppress these violent convulsions. Higher doses of the two drugs were necessary to suppress the violent convulsion. Diphenylhydantoin did not suppress either type of convulsions. It is suggested that the progressive development of seizure by PTZ is a kindling effect and that a part of the neuronal mechanisms by which the violent convulsion occurs is involved in the mechanisms underlying the clonic convulsion.
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PMID:Effect of anticonvulsants on seizures developing in the course of daily administration of pentetrazol to rats. 90 87

Similar movement disorders developed in two 8-year-old retarded children while they were receiving phenytoin. Seizures subsequent to a diphtheria-pertussis-tetanus immunization had developed in each child at 1 to 2 months of age. A static encephalopathy ensued, characterized by mental retardation, ataxia, spasticity, and a mixed seizure disorder. Intermittent dystonia and choreoathetosis developed insidiously while serum phenytoin concentrations were in the therapeutic range. Sustained dystonia and choreoatheosis developed 2 hours after an oral provocation with phenytoin. The baseline abnormalities on the electroencephalogram remained unchanged during the choreoathetosis. Recognizable metabolic abnormalities known to be associated with similar movement disorders were excluded. It was concluded from these studies that the movement disorder is secondary to phenytoin and can occur at therapeutic serum concentrations. Phenytoin is a central anticholinergic agent and a central stimulant of serotonin, and may induce movement disorders as a result of altering these neurotransmitters in the brain. The variable expression of these movement disorders may relate to the nature of the preexisting striatal insult.
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PMID:Phenytoin-induced dystonia and choreoathetosis in two retarded epileptic children. 94 1

Phenytoin, phenobarbital, ethosuximide, and procaine hydrochloride were evaluated for their ability to inhibit Ca2+ flux into isolated presynaptic endings (synaptosomes) prepared from rabbit neocortex. Calcium influx produced by depolarizing concentrations (69 mM) of K+ was inhibited 7% to 63% by phenytoin, phenobarbital, or procaine, whereas ethosuximide was ineffective. Decreased Ca2+ influx was observed with as little as 0.08 mM phenytoin and 0.04 mM phenobarbital. In contrast, 4 mM procaine was needed to produce an effect. These results lead to the conclusion that ability to produce membrane stabilization is not a property of all anticonvulsant drugs; however, this property may be essential for the action of drugs effective in the treatment of major seizures.
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PMID:Anticonvulsant drug mechanisms. Phenytoin, phenobarbital, and ethosuximide and calcium flux in isolated presynaptic endings. 96 45

Alumina cream epileptic focus was established in the right sensorimotor cortex in 20 split-brain cats (partial or complete). EEG and behavioral observations were made in a period ranging from 24 to 836 days. Four types of EEG changes after alumina cream injection were differentiated. These types could be related to the direct effects of brain damage and to development of epilepsy. Spikes and sharp waves and paroxysmal discharges (focal and multifocal) were observed in about 60% of the cats. Clinical seizures developed in about the same percentage of the animals. These values are below those reported for cats with intact interhemispheric commissures. Diphenylhydantoin (DPH) was given orally in a daily dose of up to 15 mg/kg body weight in 9 animals with developed epileptic EEG activity. Five of them had epileptic seizures. DPH was introduced not earlier than 1.5 months after intracortical alumina cream injection. The plasma level of DPH varied between 7-20 mug/ml. This dose produced chronic symptoms of intoxication. Neither EEG changes nor clinical seizures were entirely controlled by this drug. Additional doses of Relanium (diazepam), and phenobarbital were necessary to stop generalized seizures or status epilepticus.
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PMID:EEG and clinical studies of the development of alumina cream epileptic focus in split-brain cats. 97 16

Plasma phenytoin levels were measured in 60 patients under steady-state conditions for a period of six weeks. During the trial, the preparation of phenytoin was changed from Phenytoin BP (Regent) to Epanutin Infatabs. A significant increase in plasma phenytoin levels following the change of tablet was matched by a decrease in the number of seizures.
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PMID:Bioavailability of phenytoin. A comparison of two preparations. 124 84

Cerebral angiography, performed after a seizure in a patient with a life-long history of typical hemiplegic migraine, disclosed markedly dolichoectatic anterior and middle cerebral arteries. No abnormality of the adjacent capillary or venous structures was present. A positive brain scan was attributed to ischemia induced by vasospasm rather than to the corresponding large tortuous anterior and middle cerebral arteries. There were no permanent sequelae and the patient has been free of seizures on Dilantin and phenobarbital over a 3-year follow-up period. Angiographic demonstration or description of a similar ectatic set of anterior and middle cerebral arteries could not be found in the literature. The concurrence of seizures and hemiplegic migraine adds to the peculiarity of this case.
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PMID:Cerebral arterial dolichoectasia with seizure. Case report. 125 41

The purpose of this work was to assess the effects of DPH on a developed epileptogenic focus in cats with split cerebral hemispheres. The investigations were carried out on 12 cats with a chronic epileptogenic focus produced by means of aluminum method in the right motor area. In all cats the epileptogenic focus was found in EEG. All animals received DPH in daily doses of 8-15 mg/kg. In 2 cats they appeared before beginning of treatment. One of these cats died after 3 days from status epilepticus, the other survived status epilepticus and died after 42 days of DPH administration with signs of intoxication. In 3 cats clinical seizures developed during DPH treatment after 30.84 and 210 days. DPH was given during from 171 to 314 days. Clinical seizures appeared in these cats only sporadically and the animals were sacrificed after completion of investigations. In 7 out of 12 cats clinical seizures failed to develop despite presence of bioelectrically active epileptogenic seizures in the right motor area. Administration of DPH in cats with developed epileptogenic focus failed to prevent clinical seizures. In cats with seizures their control was limited by drug toxicity. In all animals toxic effects were observed although the serum DPH level was in the range 8-20 mug/ml.
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PMID:[Effect of diphenylhydantoin on a developed epileptogenic focus in cats with split cerebral hemispheres]. 126 39


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