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Query: UMLS:C0036572 (seizures)
 80,221 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The i.v. pentylenetetrazol seizure threshold was increased by 2.5 mg/kg and decreased by 15 mg/kg of a single (+)-amphetamine dose. After 7 consecutive days of amphetamine administration, tolerance developed to the decrease but not to the increase in seizure threshold. At 12--48 h after the last dose of 2.5 mg/kg seizure threshold was decreased, and at 36--48 h after the last dose of 15 mg/kg seizure threshold was increased. After acute and chronic administration of (+)-amphetamine (2.5 mg/kg) endogenous concentrations of whole brain dopamine (DA) were increased and returned to normal levels during the withdrawal period (12--48 h); endogenous norepinephrine (NE) levels were unchanged by acute and chronic drug treatment and during withdrawal. The rates of DA and NE synthesis were increased by chronic amphetamine administration at 24--48 h after drug withdrawal. An acute dose of (+)-amphetamine (15 mg/kg) decreased endogenous levels of DA and NE; normal levels of DA were detected with chronic drug treatment and during withdrawal, with NE remaining slightly depressed. The rates of synthesis of DA and NE were increased by acute and chronic amphetamine treatment and returned to normal 24--48 h after withdrawal. The rebound reversal in seizure threshold after (+)-amphetamine withdrawal suggests an abstinence syndrome that may be interpreted as evidence for the development of physical dependence to (+)-amphetamine after chronic drug administration.
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PMID:The effects of chronic administration and withdrawal of (+)-amphetamine on seizure threshold and endogenous catecholamine concentrations and their rates of biosynthesis in mice. 40 70

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

HIV-1-related neurological diseases, excluding opportunistic infections and HIV encephalitis, are considered here. Most occur in severely immunosuppressed patients, with CD4 counts of under 200 x 10(6) l-1. Primary brain lymphoma and metastases from systemic non-Hodgkin's lymphoma, the second commonest cause of cerebral mass lesions in AIDS, are usually aggressive B cell tumours. Their poor median survival after treatment, compared with that of lymphomas in non-AIDS patients, seems related to systemic complications, particularly opportunistic infections. Kaposi's sarcoma produces neurological symptoms exceptionally. Cerebral infarction is often unrecognized clinically but large vessel arteritic occlusions may occur. Intracranial haemorrhages occur mostly in thrombocytopenic patients. Seizures are frequently referred to the neurologist; investigation may lead to a diagnosis of AIDS. Nearly 50% of patients with seizures have cerebral toxoplasmosis or cryptococcal meningitis; HIV-1 encephalitis is presumed to be the cause in 30%. A subacute or chronic vacuolar myelopathy with pyramidal and posterior column signs is the commonest form of spinal cord involvement in AIDS; its cause remains unknown. Peripheral nerve syndromes occur at all stages of HIV-1 infection. Distal symmetrical peripheral neuropathies are the most frequent, particularly a painful form with axonal atrophy, associated with CMV infection, and seen during ARC or AIDS. Mononeuritis multiplex due to vasculitis, CMV, or lymphoma and a serious lumbosacral polyradiculopathy due to CMV are infrequent. The commonest myopathy is due to zidovudine (AZT); it usually responds to drug withdrawal. The nature, prognosis and optimal management of most other myopathies is yet to be determined.
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PMID:Other neurological diseases in HIV-1 infection: clinical aspects. 134 49

We studied 60 patients with juvenile myoclonic epilepsy (JME). There was a high positive family history for epilepsy (33.3%). Age at onset of epilepsy ranged from 4 to 18 years with an average of 13.9 years. 88.3% of patients were seizure-free. The most effective drug was valproate. In eight patients drug withdrawal was attempted but all patients relapsed during a follow-up period of 1 year. Video-EEG studies were performed in eight newly diagnosed patients; myoclonic jerks were recorded in five patients.
Seizure 1992 Dec
PMID:Juvenile myoclonic epilepsy of Janz: clinical observations in 60 patients. 134 79

The MRC Antiepileptic Drug Withdrawal Study compared seizure control and the risk of relapse resulting from policies of slow discontinuation and routine maintenance of antiepileptic drug (AED) treatment in patients seizure-free for > or = 2 years. Because the decision to discontinue AEDs can have important psychosocial as well as medical consequences, we also sought to examine the psychosocial outcomes of the alternative policies Questionnaires were sent to eligible adults 2 years after their randomization. The response rate was 85%. There was little evidence of substantial effects of treatment policy on psychosocial outcomes, but seizure recurrence since randomization was associated with increased distress on several measures. However, receiving AEDs to control seizures was also associated with increased distress. Among patients for whom the risk of relapse after discontinuation appears low, the psychosocial benefits of discontinuation may be considerable.
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PMID:Psychosocial outcomes of antiepileptic drug discontinuation. The Medical Research Council Antiepileptic Drug Withdrawal Study Group. 146 74

Flumazenil is a new drug indicated for the reversal of the sedative effects of benzodiazepines mediated at the benzodiazepine-receptor site. Worldwide sources to date have disclosed 43 cases of seizures related, at least temporally, to the intravenous administration of flumazenil. There was no apparent relationship between the dose of flumazenil and the development of seizures, which occurred at doses ranging from 0.2 to 10.0 mg. The seizures were not considered to be a toxic effect of flumazenil, but many of them probably were due to an unmasking of the anticonvulsant effect of the previously used benzodiazepine or to a severe benzodiazepine-withdrawal syndrome. Eighteen (42%) of the patients had ingested overdoses of cyclic antidepressants, which were considered responsible for the seizures. In addition to patients with concurrent cyclic antidepressant poisoning, high-risk populations include patients who have been treated with benzodiazepines for a seizure disorder or an acute convulsive episode, patients with concurrent major sedative-hypnotic drug withdrawal, patients who have recently been treated with repeated doses of parenteral benzodiazepines, and overdose patients with myoclonic jerking or seizure activity before flumazenil administration. To minimize the likelihood of a seizure, it is recommended that flumazenil not be administered to patients who have used benzodiazepines for the treatment of seizure disorders or to patients who have ingested drugs (eg, cyclic antidepressants, cocaine, lithium, methylxanthines, isoniazid, propoxyphene, monoamine oxidase inhibitors, buproprion HCl, and cyclosporine) that place them at risk for the development of seizures.
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PMID:Flumazenil and seizures: analysis of 43 cases. 161 50

Although valproic acid as well as its derivatives are effective in the treatment of some epileptic seizures, they are not free of adverse side effects. The purpose of this work was to describe the collateral clinical effects of valproic acid, the associated changes that take place in some serum laboratory parameters, and correlations among these adverse clinical effects, drug serum level and therapeutic response. One hundred patients aged 7 months to 19 years (average 5 year and 6 month old) were followed for at least 13 months. Clinical collateral effects were observed in 14% patients, anorexia and hair loss being the most frequent. One third of patients showed raised serum alkaline phosphatase and transaminases values, while lower than normal prothrombin time and platelet counts were detected in 4% and 1% of patients, respectively. In one patient treatment was interrupted because of low platelet counts which persisted in spite of drug withdrawal, but basal counts were not done, so it is not possible to establish causal relationships between both events. No correlation between adverse clinical symptoms and valproic acid plasma levels was observed. In spite of the fact that basal laboratory values were not known and that abnormal tests were not repeated for confirmation, collateral clinical effects and laboratory findings associated to treatment with valproic acid seemed not severe in this series. Anyway, taking into account drug characteristics, it should always be used with caution.
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PMID:[Adverse effects of valproic acid in epileptic infants and adolescents]. 184 42

Repeated administration of benzodiazepines (BDZs) produces dependence in man and animals and this is reflected in the phenomena of tolerance and withdrawal responses. In BDZ-dependent animals the BDZ-receptor antagonist flumazenil (Ro 15-1788) reverses the increased anxiety and decreased seizure threshold seen when benzodiazepine treatment is withdrawn. In contrast are reports that flumaenil enhances BDZ-withdrawal responses. Indirect influences on the direction of flumazenil's effects on anxiety are the duration and dose of BDZ treatment, whether tolerance has developed to its anxiolytic effect and whether there is an anxiogenic response on drug withdrawal. However, we conclude that the crucial factor is the anxiety level of the animal: when this is high flumazenil becomes anxiolytic; when this is low flumazenil is anxiogenic. These bidirectional effects of flumazenil can be seen in drug-naive and BDZ-dependent animals. We propose a theory of benzodiazepine dependence that can account for anxiogenic responses on drug withdrawal and for flumazenil's bidirectional effects; central to this theory is the assumption that flumazenil normalises the benzodiazepine receptor, returning it to a baseline state. Thus it is whether an animal's score lies above or below this baseline that will determine the direction of flumazenil's effect. The clinical implications of this theory are discussed. We suggest that during the development of benzodiazepine dependence, two independent adaptive biochemical mechanisms are triggered: one underlying the development of tolerance to the anxiolytic responses, the other underlying the incidence of increased anxiety on drug withdrawal. It is only changes in the latter that are induced by the administration of flumazenil.
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PMID:A theory of benzodiazepine dependence that can explain whether flumazenil will enhance or reverse the phenomena. 197 8

Juvenile myoclonic epilepsy is an age-related form of idiopathic generalized epilepsy (mean age of onset: 12-14 years). The diagnosis is based on a cluster of clinical features: types of seizures, namely myoclonic jerks associated with generalized tonic-clonic or clonic-tonic-clonic seizures in 90% of the cases, absence seizures in one third of the cases; triggering factors and circadian rhythm of seizures on awakening or after sleep deprivation; a characteristic EEG pattern, i.e. bilateral symmetrical polyspike-waves. The clinical pattern is so suggestive that in clinical practice EEG is not necessary. Seventy percent of the patients are seizure-free with one-drug therapy. Treatment must be life-long, as relapse occurs in most cases after drug withdrawal, whatever the duration of control.
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PMID:[Juvenile myoclonic epilepsy]. 212 23

Many classes of pharmacological agents have been implicated in cases of drug-induced seizures. The list includes antidepressant drugs, lithium salts, neuroleptics, antihistamines (H1-receptor antagonists), anticonvulsants, central nervous system stimulants, general and local anaesthetics, antiarrhythmic drugs, narcotic and non-narcotic analgesics, non-steroidal anti-inflammatory drugs, antimicrobial agents, antifungal agents, antimalarial drugs, antineoplastic drugs, immunosuppressive drugs, radiological contrast agents and vaccines. For each of these classes of drugs, this article offers a revision of the literature and emphasises in particular the frequency of the adverse reaction, its clinical presentation, its presumed epileptogenic mechanism and the therapeutic strategy for the management of drug-induced seizures. An attempt is also made to distinguish seizures induced by standard dosages from those provoked by accidental or self-induced intoxication. For some classes of drugs such as antidepressants, neuroleptics, central nervous system stimulants (e.g. theophylline, cocaine, amphetamines) and beta-lactam antibiotics, seizures are a well recognised adverse reaction, and a large body of literature has been published discussing exhaustively the major aspects of the issue; sufficient data are available also for the other classes of pharmacological agents mentioned above. In contrast, several other drugs [e.g. allopurinol, digoxin, cimetidine, protirelin (thyrotrophin releasing hormone), bromocriptine, domperidone, insulin, fenformin, penicillamine, probenecid, verapamil, methyldopa] have not been studied thoroughly under this aspect, and the only source of information is the occasional case report. This review does not address the issue of seizures induced by drug withdrawal.
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PMID:Clinical features, pathogenesis and management of drug-induced seizures. 218 49


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