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)

Felbamate (2-phenyl-1,3-propanediol dicarbamate) is a novel agent effective against maximal electroshock, pentylenetetrazol and other chemically induced seizures in mice and rats. Felbamate has been proposed as a novel anticonvulsant for the treatment of generalized tonic-clonic and complex partial seizures. In addition, felbamate has been shown to have neuroprotectant effects (in vitro and in vivo) in neonate models of cerebral ischemia. However, few existing studies have contributed to the elucidation of the mechanism of anticonvulsant and neuroprotectant action of felbamate. Because glycinergic mechanisms have been demonstrated to be involved with seizure disorders and neuroprotection, we investigated the binding interaction of felbamate with strychnine-insensitive glycine receptors and compared these findings with brain and plasma levels of felbamate after drug treatment. Inhibition of [3H]5,7-dichlorokynurenic acid (a high-affinity glycine receptor antagonist) binding by felbamate (IC50 = 374 microM) corresponded well with peak felbamate concentrations found in brain (683 and 759 microM) and plasma (679 and 807 microM) 8 hr after 300 (i.p.) or 500 mg/kg (p.o.) doses, respectively. Chemically diverse anticonvulsants tested and MK 801 [(+)-5-methyl-10,11-dihydro-5H-dibenzo-[a,d]cyclohepten-5,10-imine maleate] did not modulate [3H]5,7-dichlorokynurenic acid binding. Additional studies have shown that felbamate does not interact with other sites associated with the N-methyl-D-aspartate receptor complex. Thus, the data presented in this report strongly indicate a mechanism of action for felbamate through strychnine-insensitive glycine receptor interaction.
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PMID:Evidence for anticonvulsant and neuroprotectant action of felbamate mediated by strychnine-insensitive glycine receptors. 838 42

Felbamate (FBM), a newly developed antiepileptic drug (AED), was previously shown to offer some neuroprotective effects against hypoxic injury in both in vivo and in vitro studies. We administered FBM (100 or 300 mg/kg) to 30-day-old rats 1 h after they received a convulsant dosage of kainic acid (KA). Animals were then tested at age 80 days in the water maze, open field, and handling tests. Seizure latency was then tested by flurothyl inhalation. Animals that received 300 mg/kg FBM performed better in all three tests and had longer latencies to flurothyl-induced seizures than did animals that received vehicle. This study suggests that FBM may have some neuroprotective effects after KA-induced status epilepticus (SE).
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PMID:Neuroprotective effect of felbamate after kainic acid-induced status epilepticus. 845 45

Felbamate was compared with several antiepileptic drugs for protective effects in two rat models of status epilepticus. Felbamate was ten times more potent against pilocarpine-induced seizures in lithium-treated rats than in lithium-free animals. Diazepam, valproate and phenobarbital were effective in both the high dose pilocarpine and lithium-pilocarpine models. On the other hand, phenytoin was ineffective in both models, whereas carbamazepine displayed protective effects only in the lithium-pilocarpine model.
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PMID:Effects of felbamate and other anticonvulsant drugs in two models of status epilepticus in the rat. 848 78

Felbamate is a new antiepileptic drug (AED) with a good safety profile. Anorexia has been reported in patients taking felbamate, but the incidence and severity of this side effect have not been adequately investigated. We studied 65 patients with intractable seizures who received adjunctive felbamate therapy as part of clinical research trials or in a compassionate-use program. Mean treatment time on felbamate was 23 weeks (+/- SD 16; range, 6-116 weeks). Forty-nine patients (75%) lost weight during the trials. For subjects older than 15 years, there was a mean weight loss of 3.17 kg or 4.11% of body weight (T = 191.5, z = 4.18, p < 0.001). For subjects 15 years or younger there was a mean weight loss 0.20 kg or a loss of 1.77% of body weight (T = 52.5, NS). Twenty-two patients (34%) lost > 4 kg, and seven patients (11%) lost > 8 kg. Adjunctive treatment of adults with severe epilepsy with felbamate may be associated with clinically significant weight loss.
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PMID:Weight loss in patients taking felbamate. 866 31

Felbamate is a novel anti-epileptic drug (AED) which has recently been associated with reports of aplastic anaemia and liver failure. We have conducted an open-label add-on assessment of the tolerability and efficacy of this compound in 111 adult patients with refractory epilepsy attending a tertiary referral centre. The mean follow-up period was 4 months (range 1-8 months). Sixty-three (57%) were ongoing, 38 (34%) had discontinued felbamate and a further 10 (9%) were withdrawing. Reasons for discontinuing felbamate were adverse events in 23 (21%), increase in seizures in 11 (10%) and lack of efficacy in 14 (12%). Behavioural disturbances occurred in 14 patients, being the most likely adverse event to result in discontinuation. No cases of aplastic anaemia or liver failure were observed in this group. Felbamate appears to be a broad-spectrum AED. Seven percent of the patients had more than 95% seizure reduction (2 patients were seizure free), whilst a further 13% had significant improvement ( > 50% reduction in seizure frequency). In conclusion, felbamate seems to be an effective AED. In view of its association with potentially life-threatening complications, its use should however be restricted to patients with medically refractory epilepsy.
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PMID:Felbamate as add-on therapy. 873 44

Felbamate was approved in July 1993 for use alone or in combination with other antiepileptic drugs for partial seizures and Lennox-Gastaut syndrome. We report an overdose of felbamate in a teenage female patient who, in a suicide gesture, ingested eight times her maximum dose and suffered only mild side effects. This first report of a felbamate overdose is presented and followed by a discussion of felbamate's effectiveness, pharmacology, adverse effects, and drug interactions.
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PMID:Felbamate overdose: a case report and discussion of a new antiepileptic drug. 875 Nov 73

Seven patients with refractory seizure disorders and neuropsychiatric symptoms believed secondary to felbamate are presented. Five were on concomitant valproic acid (and other agents). Anergia, apathy, bradyphrenia, and increased irritability were prominent. One patient on felbamate monotherapy had a new-onset psychosis. Felbamate's NMDA receptor antagonism and GABA potentiation (perhaps enhanced by valproic acid use) are discussed as possible mechanisms of these side effects.
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PMID:Neuropsychiatric side effects related to treatment with felbamate. 901 38

The present study was designed to examine the ability of felbamate, a novel antiepileptic agent, to antagonize the increase in seizure severity (i.e., chemical kindling) produced by chronic treatment with initially subconvulsant doses of pentylenetetrazol (PTZ). Rats were treated with PTZ (30 mg/kg, i.p., three times a week) for 8 consecutive weeks. Two other groups of rats received felbamate (300 or 400 mg/kg, i.p.), 90 min before each dose of PTZ. Pretreatment with felbamate at either dose prevented the progression of rank of seizures during chronic treatment with PTZ. Thus, the mean seizure score by the end of the chronic treatment (0-5 scale) was 0 in vehicle treated controls, 3.3 in rats treated with PTZ alone, 1.5 in rats treated with PTZ plus felbamate (300 mg/kg, i.p.) and 0.9 in the group treated with PTZ plus felbamate (400 mg/kg, i.p.). Felbamate also antagonized the long-term increase in the sensitivity to the convulsant effects of GABA function inhibitors observed in PTZ-kindled rats. Thus, the administration of a challenge dose of isoniazid (120 mg/kg, s.c.), picrotoxin (1.5 mg/kg, i.p.) or PTZ itself (15 mg/kg, i.p.), 15 to 45 days after the end of the chronic treatment regimen, induced convulsions in > 80% of PTZ-kindled rats and in < 20% of rats treated with PTZ + felbamate (400 mg/kg). The results are discussed in terms of the multiple mechanisms that can contribute to the anticonvulsant action of felbamate in the PTZ kindling model of epilepsy.
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PMID:Anticonvulsant effect of felbamate in the pentylenetetrazole kindling model of epilepsy in the rat. 885 94

A totally automated analysis of felbamate was developed by using a robotized PrepStation for extraction, followed by automated liquid chromatographic (LC) analysis and data reduction. This is one of the newer direct-sample analysis approaches by LC. Felbamate was a previously approved antiepileptic agent used to treat partial seizures with and without generalization and to treat Lennox-Gastaut syndrome in pediatric patients. However, due to the reported incidences of aplastic anemia, its clinical application was recently restricted to the treatment of the latter syndrome. The automated assay using Bench Supervisor, PrepStation, and LC, based on a previously developed manual method, used 200 microliters of serum standards, quality control, or patients' plasma. These were mixed with 600 microliters of internal standard (IS) W509 dissolved in acetonitrile for protein precipitation. After axial centrifugation and standing, aliquots of the clear supernatant were transferred and washed with hexane. Aliquots of the supernatant were transferred and injected into a high-performance liquid chromatograph (HPLC). HPLC parameters included an mu Bondapak C-18 column, phosphate/acetonitrile (8:2) as mobile phase, and detection at 214 nm. Retention times were 2.9 and 4.2 min for felbamate and IS, respectively. Calibration was linear for concentrations from 10 to 200 mg/L with r > 0.994. Precision studies showed coefficients of variation ranging from 2.7% to 8.8%. Correlation with the manual method showed that r = 0.934, slope = 1.048, intercept = -2.642, and n = 21. Phenobarbital coeluted with the IS. This study demonstrated the feasibility of using a robotized, automated method for monitoring felbamate, readily extended to monitoring other antiepileptic drugs with minimal modification.
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PMID:Totally automated analysis by robotized PrepStation and liquid chromatography: direct-sample analysis of felbamate. 888 22

1. After a hiatus of over 20 years, several new antiepileptic drugs (vigabatrin, lamotrigine, gabapentin, oxcarbazepine, topiramate, felbamate, zonisamide and tiagabine) have reached or approached the registration phase. 2. Compared with older agents, many new drugs exhibit simpler pharmacokinetics. This is especially true for vigabatrin and gabapentin, which are renally eliminated and have a low interaction potential. 3. Unlike most of the older agents, vigabatrin, lamotrigine, gabapentin and tiagabine are devoid of significant enzyme inducing or inhibiting properties. Topiramate, oxcarbazepine and felbamate may induce the metabolism of steroid oral contraceptives. In addition, felbamate also acts as a metabolic inhibitor. 4. To date, the efficacy of new drugs has been evaluated extensively only under add-on conditions in patients with partial seizures (with or without secondary generalization) refractory to conventional treatment. However, there is evidence that lamotrigine, zonisamide, felbamate and, possibly, topiramate may also be effective in generalized epilepsies. 5. In placebo-controlled studies, typically between 15 and 40% of patients with difficult-to-treat partial epilepsy have shown an improvement (defined as a 50% or greater decrease in seizure frequency) after addition of a new drug. Only a small minority of these patients achieved complete seizure control. 6. Compared with older agents, some of the new drugs may have a better tolerability profile. Felbamate, however, has been associated with a high risk of aplastic anaemia and hepatotoxicity. 7. At present, the main use of the new agents is in patients refractory to first-line drugs such as carbamazepine or valproate, and further studies are required to characterize their activity spectrum as well as their potential value in monotherapy. In most patients, new drugs cannot be recommended for first-line use until evidence is obtained that potential advantages in tolerability or ease of use outweigh the drawback of their high cost.
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PMID:The new generation of antiepileptic drugs: advantages and disadvantages. 895 Nov 84


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