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)

At present there is a poor understanding of the events that lead up to neuronal apoptosis that occurs in neurodegenerative diseases and following acute ischemic episodes. Apoptosis is critical for the elimination of unwanted neurons within the developing nervous system. The Bcl-2 family of proteins contains pro- and anti-apoptotic proteins that regulate the mitochondrial pathway of apoptosis. There is increasing interest in a subfamily of the Bcl-2 family, the BH3-only proteins, and their pro-apoptotic effects within neurons. Recently ischemic and seizure-induced neuronal injury has been shown to result in the activation of the BH3-only protein, Bid. This protein is cleaved and the truncated protein (tBid) translocates to the mitochondria. The translocation of tBid to the mitochondria is associated with the activation of outer mitochondrial membrane proteins Bax/Bak and the release of cytochrome C from the mitochondria. ER stress also has been implicated as a factor for the induction of apoptosis in ischemic neuronal injury. The induction of ER stress in hippocampal neurons has been shown to activate expression of bb3/PUMA, a member of the BH3-only gene family. Activation of PUMA is associated with the activation and clustering of the pro-apoptotic Bcl-2 family member Bax and the loss of cytochrome C from the mitochondria.
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PMID:Neuronal apoptosis: BH3-only proteins the real killers? 1537 60

The fact that so many varied medications reportedly affect taste and smell is a testament to the complexity of the gustatory and olfactory systems. The reception, transduction, propagation, and perception of a chemical tastant or odorant requires the effective operation of numerous mechanisms--all of which may be susceptible in one way or another to a prescribed medication. Just as a diuretic may block the apical ion channels on a taste bud, or an antifungal can inhibit cytochrome p450-dependent enzymes at the level of the receptors, a chemotherapeutic agent can destroy mitosis in a replicating receptor cell and a steroid can lead to candidal overgrowth on the tongue surface. Medications not only have a perceivable taste themselves at times, but they can alter the mechanisms responsible for the ultimate perception of tastes and smells--either by direct or secondary means. It should be emphasized, as noted earlier in this article, that while many medications are to blame for the impairment or distortion of the gustatory or olfactory systems, it is not uncommon that the underlying medical problem for which they are prescribed is actually the culprit. Examples include epilepsy, migraines, hypothyroidism, schizophrenia, infections, and cancer. In fact, simple partial seizures emanating from regions of the brain such as the amygdala, hippocampus, parietal operculum, and rolandic operculum can lead to the chemosensory sensations that are most commonly considered unpleasant, such as "rotten apples," "cigarette," "peculiar," or "vomitus". While removing or changing an offending medication can reverse the effects on smell or taste perception, it is important to remember that lasting impairment may occur. This is vital for a physician to recognize prior to prescribing a medication. It is also necessary to report this to patients who may be devastated by chemosensory alterations after starting a new medication (eg, pastry chef, perfumist, wine specialist, plumber). Among the "risks" in a risks/benefits discussion with a patient regarding the use of a new medication, alterations in olfaction and taste appear to play an increasingly recognized role.
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PMID:Effects of drugs on olfaction and taste. 1556 12

South Africa, with a population of 44.8 million, has over 5 million human immunodeficiency virus (HIV)-infected individuals. Over 70% of HIV-infected patients will present with clinically relevant neurologic disease at some stage during the course of their disease. New onset seizures occur in 3-11% of these patients. The mechanism of seizure production in HIV-positive patients includes incidental association, HIV itself, opportunistic infections (OIs), neoplasia, cerebrovascular disease, drug toxicity, and metabolic derangements. In developing countries, OIs constitute the largest group presenting with seizures. Seizure management in HIV-positive patients presents special problems, especially with respect to drug-disease and drug-drug interactions. The older antiepileptic drugs (AEDs) are protein-bound and largely depend on the cytochrome p450 system for their metabolism. The newer AEDs may be safer in patients on antiretroviral drugs. However, they are expensive, an important consideration in developing countries.
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PMID:Seizures in HIV/AIDS: a southern African perspective. 1623

Homocystein (Hcy) is regarded as a neuroexcitatory substance, which is therefore used as an epileptogenic agent in experimental epileptology. Experiments "in vivo" as well as "in vitro" revealed its relation to NMDA glutamate receptors, and its potential neurotoxicity. From the clinical aspect, hyperhomocysteinemia (HHcy), mostly as a marker of the risk factor in the vascular damage, was often studied in patients treated with antiepileptic drugs (AE). However, the neuroexcitatory influence of mild HHcy (up to 30 micromol/l) was rarely discussed. Out of a group of 123 adult patients on long-term conventional AE we analyzed 8 patients (7 men and one woman) with moderate to severe HHcy (30.7-109.0 micromol/l) retrospectively and 2-5 years after HHcy normalization. All of them suffered from partial and/or secondary generalized seizures accompanied by neuropsychological impairment depending on the aetiology of the disease. The patients were characterized by a concurrence of several factors: (1) All of them received conventional AEs inducing the cytochrome P 450 at the time HHcy was diagnosed. (2) Molecular-genetic tests showed enzymopathic impairment (methylentetrahydrofolate reductase-MTHFR mutation of the gene C677 T) also in all eight, homozygous in 7 cases and heterozygous in 1 case. (3) All patients were found to have a vitamin deficit or marginal values of at least one of the vitamins under study, especially folate and/or vitamin B6 and 812. With reference to clinical and EEG features, the potential neuroexcitatory influence of Hcy is discussed taking into account its effect on pathogenetic factors.
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PMID:Moderate hyperhomocysteinemia in patients treated for epilepsy. 1706 42

Bupropion was initially developed and licensed for the treatment of major depressive disorder in the United States in 1989. It was licensed as a pharmacotherapy for smoking cessation in the United States in 1997 and in the United Kingdom in 2000, and for the prevention of seasonal major depressive episodes in patients with seasonal affective disorder in the United States in 2006. Its main mechanism of action is believed to be via dopamine and noradrenalin reuptake inhibition. In addition to proven clinical efficacy for the treatment of major depression, the prevention of depressive episodes in patients with seasonal affective disorder, and as an aid to smoking cessation treatment, bupropion has demonstrated efficacy for attenuation of symptoms of attention deficit hyperactivity disorder, and more recently it has shown anti-inflammatory action against proinflammatory cytokines such as tumor necrosis factor-alpha (TNF-alpha), which may be implicated in a number of inflammatory diseases such as Crohn's disease. The twice-daily sustained-release formulation has been extensively evaluated for smoking cessation and has shown continuous smoking abstinence rates at one year of the order of 20% across many clinical groups including healthy smokers, and smokers with cardiovascular disease, chronic obstructive airways disease, depression and schizophrenia. Bupropion is well tolerated with side effects including insomnia, headache, dry mouth, dizziness and nausea. Bupropion is a cytochrome p450 2D6 inhibitor and care must be taken when coprescribing with drugs cleared by this enzyme and when coprescribing with drugs that lower seizure threshold. Despite the clinical effectiveness and cost-effectiveness of bupropion as an aid to smoking cessation, its uptake for this indication remains low when compared with nicotine replacement therapy.
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PMID:Bupropion. 1713 26

Since 2005, increasing numbers of seizures of the designer drug of abuse 1-(3-chlorophenyl)piperazine (mCPP) have been reported. This paper describes the unequivocal proof of a mCPP intake. Differentiation from the intake of its precursor drugs trazodone and nefazodone was performed by a systematic toxicological analysis (STA) procedure using full-scan GC-MS after acid hydrolysis, liquid-liquid extraction and microwave-assisted acetylation. The found mCPP/hydroxy-mCPP ratio indicated altered metabolism of this cytochrome (CYP) 2D6 catalyzed reaction compared to published studies using the same procedure. Although this might be ascribed to a poor metabolizer (PM) phenotype, genotyping revealed no PM genotype but indications for an intermediate metabolizer genotype. However, a PM phenotype could also be caused by drug-drug interactions with CYP2D6 inhibitors or substrates such as the co-consumed cocaine and diltiazem and/or diltiazem metabolites, respectively. In conclusion, the presented data indicate a possible relevance of CYP2D6 polymorphism and/or drug interactions to mCPP toxicokinetics, which is important for risk assessment of this new designer drug of abuse, in particular if it is used as adulterant of CYP2D6 substrates such as cocaine.
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PMID:Proof of a 1-(3-chlorophenyl)piperazine (mCPP) intake: use as adulterant of cocaine resulting in drug-drug interactions? 1757 34

Levetiracetam is a new antiepileptic drug reported to be effective and well-tolerated in adults and children affected by epilepsy. Its lack of hepatic cytochrome metabolism is the theoretic basis for the absence of interactions with other drugs that follow this pathway. We present a 14-year-old girl who underwent orthotopic heart transplantation, followed by antirejection therapy including cyclosporine. Symptomatic occipital lobe epilepsy developed that was successfully treated with oxcarbazepine, but cyclosporine plasma levels decreased to below the antirejection threshold. Oxcarbazepine was replaced by levetiracetam. Levetiracetam did not affect the metabolism of cyclosporine, and cyclosporine plasma levels have remained in the therapeutic range up to now. The patient is still seizure-free and does not complain of any side effects after a 1-year follow-up. Further studies are necessary to confirm the lack of interactions between these drugs, which would make levetiracetam a useful therapeutic option in managing seizure control during antirejection therapy with cyclosporine.
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PMID:No kinetic interaction between levetiracetam and cyclosporine: a case report. 1762 25

Special treatment considerations are warranted in women with epilepsy, particularly those of childbearing age. Treatment guidelines generally recommend the use of antiepileptic drug (AED) monotherapy at the lowest dose possible during pregnancy. The UK Epilepsy and Pregnancy Register reported that the risk for major congenital malformations is higher with AED polytherapy than with monotherapy (6.0% vs 3.7%, respectively) and that valproate carries the highest individual risk. The AEDs that induce hepatic cytochrome CYP450 enzymes carry particular concern both before and after pregnancy. Hepatic enzyme inducers alter steroid metabolism in women receiving oral contraceptives, increase the risk for contraceptive failure, and interfere with calcium absorption and vitamin D metabolism, thus increasing the risk for osteoporosis and fractures. Vitamin K deficiency is another potential consequence of treatment with a hepatic enzyme-inducing AED, increasing the risk for coagulopathy and neonatal intraparenchymal and intracerebral hemorrhage during the first 24 hours of life. Supplemental vitamin K therapy during the last month of pregnancy is warranted. Preconceptional and gestational folate supplementation may also be warranted to prevent neural tube malformation related to AED treatment. Because AED pharmacokinetics may be altered during pregnancy, plasma AED concentrations should be measured before conception and monthly during pregnancy to prevent seizure breakthrough.
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PMID:Importance of monotherapy in women across the reproductive cycle. 1807 Nov 52

Levetiracetam (LEV) is a broad-spectrum antiepileptic drug that is effective against a variety of seizure types. It is a pyrridoline derivative with a very favourable pharmacokinetic profile: excellent bioavailability, linear kinetics, minimal plasma protein binding and quick achievement of steady state concentrations. It is not metabolized through the P450 hepatic cytochrome system, does not induce its own metabolism and has no clinically relevant drug-drug interactions. It is available as film-coated tablets, liquid formulation for oral ingestion and intravenous concentrated solution. Controlled and open-label studies have shown its efficacy and safety as initial monotherapy and add-on treatment for partial-onset seizures in children and adults, and also as add-on therapy in refractory partial and primary generalized seizures. Its rapid onset of action, lack of drug-drug interactions and availability as an intravenous solution make it an optimal drug to treat epilepsy associated with other medical conditions. Preliminary reports also suggest potential efficacy in refractory status epilepticus, although this is not a registered indication. Levetiracetam is generally well tolerated, and no serious idiosyncratic side effects have been reported so far. Behavioral side effects (hostility up to aggressive behaviour) are not uncommon. Small, uncontrolled studies have suggested potential therapeutic potential in difficult-to-treat dyskinesias in Parkinson's disease, tremors of different etiologies, migraine prophylaxis and mood disorders. This needs to be confirmed in larger, controlled studies.
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PMID:Levetiracetam. 1817 64

The constitutive isoform of heme oxygenase, HO-2, is highly expressed in the brain and in cerebral vessels. HO-2 functions in the brain have been evaluated using pharmacological inhibitors of the enzyme and HO-2 gene deletion in in vivo animal models and in cultured cells (neurons, astrocytes, cerebral vascular endothelial cells). Rapid activation of HO-2 via post-translational modifications without upregulation of HO-2 expression or HO-1 induction coincides with the increase in cerebral blood flow aimed at maintaining brain homeostasis and neuronal survival during seizures, hypoxia, and hypotension. Pharmacological inhibition or gene deletion of brain HO-2 exacerbates oxidative stress induced by seizures, glutamate, and inflammatory cytokines, and causes cerebral vascular injury. Carbon monoxide (CO) and bilirubin, the end products of HO-catalyzed heme degradation, have distinct cytoprotective functions. CO, by binding to a heme prosthetic group, regulates the key components of cell signaling, including BK(Ca) channels, guanylyl cyclase, NADPH oxidase, and the mitochondria respiratory chain. Cerebral vasodilator effects of CO are mediated via activation of BK(Ca) channels and guanylyl cyclase. CO, by inhibiting the major components of endogenous oxidant-generating machinery, NADPH oxidase and the cytochrome C oxidase of the mitochondrial respiratory chain, blocks formation of reactive oxygen species. Bilirubin, via redox cycling with biliverdin, is a potent oxidant scavenger that removes preformed oxidants. Overall, HO-2 has dual housekeeping cerebroprotective functions by maintaining autoregulation of cerebral blood flow aimed at improving neuronal survival in a changing environment, and by providing an effective defense mechanism that blocks oxidant formation and prevents cell death caused by oxidative stress.
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PMID:Cerebroprotective functions of HO-2. 1828 71


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