Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0004134 (ataxia)
 15,886 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The anticonvulsant potency of the trans isomer of 2-en-valproate (trans-2-en-VPA) was determined in standardized models for different seizure types in rodents and dogs. In mice and rats, adverse effects were quantified by the rotarod and chimney tests. Clinically established antiepileptic drugs (valproate, ethosuximide, phenobarbital, carbamazepine, phenytoin, diazepam) were used for comparison. Based on time course studies, drug potencies were determined and compared at the individual time of peak anticonvulsant effect. Potency comparisons were based on administered dosages and, in the case of trans-2-en-VPA and valproate, also on plasma levels determined after administration of anticonvulsant doses. The data show that trans-2-en-VPA exerts anticonvulsant effects against different seizure types, i.e., myoclonic, clonic, and tonic seizures in rodents and (myo)clonic seizures in dogs. In most seizure models, trans-2-en-VPA was more potent than valproate, when both compounds were compared at their individual times of peak effect. Time course and pharmacokinetic studies showed that duration of action and pharmacokinetic characteristics of trans-2-en-VPA and valproate are similar. In the rotarod and chimney tests in mice and rats, trans-2-en-VPA was more potent than valproate. However, because of the higher anticonvulsant potency of trans-2-en-VPA, protective indices calculated from rodent models were similar to those of valproate. Similarly, in dogs trans-2-en-VPA exerted anticonvulsant effects at doses below those which induced sedation and ataxia. In view of the previously reported advantages of trans-2-en-VPA compared to valproate with respect to teratogenic and hepatotoxic effects, the present data substantiate that trans-2-en-VPA might be a valuable alternative to valproate in antiepileptic therapy.
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PMID:Trans-2-en-valproate: reevaluation of its anticonvulsant efficacy in standardized seizure models in mice, rats and dogs. 174 83

Amygdala-kindled rats were treated with valproic acid (VPA; administered as its sodium salt) 3 times daily at 200 mg/kg i.p. for 6 weeks, and anticonvulsant and adverse effects during this period were studied. Groups of nonkindled rats were treated in parallel for determination of VPA and its major active metabolites in various brain regions after different durations of treatment. After the first injection of VPA, 200 mg/kg, seizure severity, seizure duration and duration of electrical afterdischarges recorded from the stimulated amygdala were reduced significantly, but only one of nine animals was protected completely from kindled seizures. At day 3 of chronic treatment, the anticonvulsant activity of VPA had increased markedly so that seven of nine animals were totally protected from seizures. However, this potent anticonvulsant effect was only transitory so that after 1 week of treatment the anticonvulsant effect of the medication was similar to that obtained after the first dosing. The effect of VPA remained at this level for the subsequent weeks, but there was a second, more permanent increase in the number of protected animals after 4 to 6 weeks. Plasma and brain levels of VPA and its metabolites remained relatively constant throughout the chronic treatment although there was a moderate accumulation of some metabolites, e.g., trans isomer of 2-propyl-2-pentenoic acid, in specific brain nuclei. The most prominent adverse effects of VPA were ataxia, muscle relaxation, wet-dog shake behavior and an increase in body temperature. Except for body temperature, tolerance developed to these adverse effects, but escape from wet-dog shake behavior occurred much more rapidly than reduction of other adverse effects. Pathohistological examination of liver sections from animals treated with VPA for 6 weeks showed no indication of any hepatotoxic effects. After drug withdrawal, kindled seizure parameters returned toward control values without evidence of significant carry-over effects. Five days after termination of treatment, only minute amounts of VPA and trans isomer of 2-propyl-2-pentenoic acid were determined in some brain regions, indicating that there was no persistence of active drug or metabolite concentrations in the brain.
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PMID:Valproic acid in amygdala-kindled rats: alterations in anticonvulsant efficacy, adverse effects and drug and metabolite levels in various brain regions during chronic treatment. 250 34

Sodium valproate was administered to 38 patients, admitted to our unit in the last 18 months, and chosen because they had: (1) poor control of their seizures; (2) therapeutic concentrations in their plasma of at least two major antiepileptic drugs. In 8 of them, a therapeutic dosage of VPA caused modifications of the state of consciousness ranging from coma to drowsiness and stupor. These patients also showed gastrointestinal disturbances, asterixis, ataxia, tremor and a worsening of EEG abnormalities. The side effects of the drug were constantly associated with increased concentration of blood ammonia. Better penetration of ammonia into the CNS of patients undergoing frequent seizures and possibly having imperfectly functioning biological barriers, could explain our observations. In view of the unusually high percentage of patients suffering from serious VPA side effects, it is probably advisable to carefully monitor ammonemia in the first few days of VPA therapy in every patient treated with multiple anticonvulsants.
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PMID:Hyperammonemia and valproate-induced alterations of the state of consciousness. A report of 8 cases. 642 61

Valproic acid is a branched-chained fatty acid, structurally unrelated to any other antiepileptic drug. Since publication of the original review in the Journal in 1977, several clinical trials have documented its efficacy and safety in adults and children for the treatment of generalised seizures (absence, tonic-clonic, myoclonic), partial seizures (simple, complex, secondarily generalised) and compound/combination seizures (including those refractory to treatment with other antiepileptic drugs). Valproic acid monotherapy has demonstrated efficacy equivalent to that of carbamazepine, phenytoin, and phenobarbital in the treatment of both generalised and partial seizures and ethosuximide in the treatment of absence seizures. Adverse effects associated with the drug are primarily gastrointestinal (nausea, vomiting, dyspepsia) in nature, although the use of enteric-coated formulations has reduced the incidence of abdominal discomfort. Weight gain, tremor and transient hair loss are commonly reported. Importantly, valproic acid has minimal neurological adverse effects (sedation, ataxia, impairment of cognitive function) compared with other antiepileptic drugs, a finding that may be of particular relevance in many patients with epilepsy. The incidence of rare, fatal liver failure has been greatly reduced by identifying and avoiding administration of valproic acid to high risk patient populations. An estimated risk of 1 to 2% for neural tube defects, predominantly spina bifida aperta, with maternal use of valproic acid therapy has been reported. Valproic acid inhibits hepatic drug metabolism and displaces other highly bound drugs from their plasma protein binding sites. Therefore, coadministered drugs which are highly protein bound or hepatically metabolised may require dosage adjustment. Enzyme-inducing antiepileptic drugs may increase valproic acid metabolism and necessitate increasing its dosage. Thus, comparative trials and extensive clinical experience have demonstrated the efficacy and tolerability of valproic acid and support its role as a valuable and well established first-line treatment for patients with a broad range of seizure types.
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PMID:Valproic acid. A reappraisal of its pharmacological properties and clinical efficacy in epilepsy. 751 5

The anticonvulsant valproic acid (VPA), or 2-propylpentanoic acid, is a short-chain aliphatic acid that is teratogenic in humans and rodents. VPA and 14 related chemicals were screened for developmental toxicity using the Chernoff/Kavlock assay. Test agents, in corn oil, were administered by gavage to Sprague-Dawley rats once daily during organogenesis. The dams were allowed to deliver and the pups were examined postnatally. Segment II studies were also conducted using VPA and pentanoic acid in rats and with VPA in CD-1 mice. In both mice and rats, VPA caused transient maternal ataxia and developmental defects of the digits and, especially, the axial skeleton. Exencephaly, however, was seen only in mice. The screening protocol was effective in prioritizing agents within this class of compounds for more definitive developmental toxicity testing. All congeners tested induced maternal respiratory effects and six compounds caused motor depression. Only 2-ethylhexanoic (2EH) and 2-propylhexanoic (2PH) acid caused dramatic VPA-like effects on rat development (including mortality, extra presacral vertebrae, fused ribs, and delayed parturition), confirming the strict structural requirements for developmental toxicity previously reported for acute exposure in mice. The incorporation of skeletal examinations in the Chernoff/Kavlock assay enabled the detection of the sole developmental effect (increased incidence of lumbar ribs) of 2-butylhexanoic acid. VPA, 2EH, and 2PH were among the compounds that caused maternal motor depression. These data, consistent with previous reports, indicate a broader specificity for activity in the adult nervous system than that in the developing system and suggest differing mechanisms for the two effects.
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PMID:Developmental toxicity and structure-activity relationships of aliphatic acids, including dose-response assessment of valproic acid in mice and rats. 800 77

Three hundred and forty seven patients with epilepsy from 54 centres across Europe not fully controlled with sodium valproate (VPA, n = 117), carbamazepine (CBZ, n = 129), phenytoin (PHT, n = 92) or phenobarbital (PB, n = 9) monotherapy were recruited into a lamotrigine (LTG) substitution study. If 50% or more seizure reduction occurred (responders) on addition of LTG, an attempt was made to withdraw the original antiepileptic drug (AED). If successful, this was followed by a 12 week period of LTG monotherapy. Overall, 73% patients completed the add-on phase (47% responders), 41% attempted AED withdrawal and 23% achieved LTG monotherapy. In the 60 patients (17%) completing the trial by remaining on LTG monotherapy, median monthly seizure frequency was reduced from 6 during baseline to 1.7. Sixteen percent of patients were withdrawn due to adverse effects, mostly during the add-on phase. Dizziness and diplopia occurred most frequently in the CBZ group, nervousness and ataxia in the PHT group, and rash and tremor in the VPA group. Slower LTG dose escalation resulted in fewer withdrawals due to rash in the VPA-treated patients (38% to 8%, P < 0.01). The responder rate was higher (P < 0.01) in patients with idiopathic tonic-clonic seizures (61%) than in those with partial seizures (43%). The addition of LTG to VPA (64% responders) produced a significantly better response (P < 0.001) than adding it to CBZ (41% responders) or PHT (38% responders). This effect was seen for partial (VPA, 57%; CBZ, 39%; PHT, 39%; P < 0.02) as well as tonic-clonic seizures (VPA, 70%; CBZ, 53%; PHT, 50%; NS). These data lend credence to the suggestion of therapeutic synergy between LTG and VPA.
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PMID:Lamotrigine substitution study: evidence for synergism with sodium valproate? 105 Study Group. 912 23

Panic disorder, a psychiatric disorder characterised by frequent panic attacks, is the most common anxiety disorder, affecting 2 to 6% of the general population. No one line of treatment has been found to be superior, making a risk-benefit assessment of the treatments available useful for treating patients. Choice of treatment depends on a number of issues, including the adverse effect profile, efficacy and the presence of concomitant syndromes. Tricyclic antidepressants (TCAs) are beneficial in the treatment of panic disorder. They have a proven efficacy, are affordable and are conveniently administered. Adverse effects, including jitteriness syndrome, bodyweight gain, anticholinergic effects and orthostatic hypotension are commonly associated with TCAs, but can be managed successfully. Selective serotonin (5-hydroxytryptamine; 5HT) reuptake inhibitors are also potential first line agents and are well tolerated and effective, with a favourable adverse effects profile. There is little risk in overdose or of anticholinergic effects. Adverse effects include sedation, dyspepsia and headache early in treatment, and sexual dysfunction and increased anxiety, but these can be effectively managed with proper dosage escalation and management. Benzodiazepines are an effective treatment, providing short-term relief of panic-related symptoms. Patients respond to treatment quickly, providing rapid relief of symptoms. Adverse effects include ataxia and drowsiness, and cognitive and psycho-motor impairment. There are reservations over their first-line use because of concerns regarding abuse and dependence. Monoamine oxidase inhibitors, because of their adverse effects profile, potential drug interactions, dietary restrictions, gradual onset of effect and overdose risk, are not considered to be first-line agents. They are effective however, and should be considered for patients with refractory disease. Valproic acid (valproate sodium), while not intensively studied, shows potential for use in panic disorder. More studies are needed in this area before the available data can be confirmed. As a supplement to drug therapy, cognitive behavioural therapy is effective. It is well tolerated, and may be beneficial in certain clinical situations. Its main drawback is the time commitment and effort needed to be made by the patient.
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PMID:A risk-benefit assessment of pharmacological treatments for panic disorder. 963 87

Cluster headache and trigeminal neuralgia are relatively rare but debilitating neurologic conditions. Although they are clinically and diagnostically distinct from migraine, many of the same pharmacologic agents are used in their management. For many patients, the attacks are so frequent and severe that abortive therapy is often ineffective; therefore, chronic preventive therapy is necessary for adequate pain control. Cluster headache and trigeminal neuralgia have several distinguishing clinical features. Cluster headache is predominantly a male disorder; trigeminal neuralgia is more prevalent in women. Individuals with cluster headaches often develop their first attack before age 25; most patients with trigeminal neuralgia are between age 50 and 70. Cluster headaches are strongly associated with tobacco smoking and triggered by alcohol consumption; trigeminal neuralgia can be triggered by such stimuli as shaving and toothbrushing. Although the pain in both disorders is excruciating, cluster headache pain is episodic and unilateral, typically surrounds the eye, and lasts 15 to 180 minutes; the pain of trigeminal neuralgia lasts just seconds and is usually limited to the tissues overlying the maxillary and mandibular divisions of the trigeminal nerve. Cluster headache is unique because of its associated autonomic symptoms. Although the pathophysiology of cluster headache and trigeminal neuralgia are not completely understood, both appear to have central primary processes, and these findings have prompted investigations of the effectiveness of the newer antiepileptic drugs for cluster headache prevention and for the treatment of trigeminal neuralgia. The traditional antiepileptic drugs phenytoin and carbamazepine have been used for the treatment of trigeminal neuralgia for a number of years, and while they are effective, they can sometimes cause central nervous system effects such as drowsiness, ataxia, somnolence, and diplopia. Reports of studies in small numbers of patients or individual case studies indicate that the newer antiepileptic drugs are effective in providing pain relief for trigeminal neuralgia and cluster headache sufferers, with fewer central nervous system side effects. Divalproex has been shown to provide effective pain control and to reduce cluster headache frequency by more than half in episodic and chronic cluster headache sufferers. Topiramate demonstrated efficacy in a study of 15 patients, with a mean time to induction of cluster headache remission of 1.4 weeks (range, 1 day to 3 weeks). In the treatment of trigeminal neuralgia, gabapentin has been shown to be effective in an open-label study. When added to an existing but ineffective regimen of carbamazepine or phenytoin, lamotrigine provided improved pain relief; it also may work as monotherapy. Topiramate provided a sustained analgesic effect when administered to patients with trigeminal neuralgia. The newer antiepileptic drugs show considerable promise in the management of cluster headache and trigeminal neuralgia.
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PMID:Antiepileptic drugs in the management of cluster headache and trigeminal neuralgia. 1190 37

The central nervous system (CNS) is, after the peripheral nervous system, the second most frequently affected organ in mitochondrial disorders (MCDs). CNS involvement in MCDs is clinically heterogeneous, manifesting as epilepsy, stroke-like episodes, migraine, ataxia, spasticity, extrapyramidal abnormalities, bulbar dysfunction, psychiatric abnormalities, neuropsychological deficits, or hypophysial abnormalities. CNS involvement is found in syndromic and non-syndromic MCDs. Syndromic MCDs with CNS involvement include mitochondrial encephalomyopathy, lactacidosis, stroke-like episodes syndrome, myoclonic epilepsy and ragged red fibers syndrome, mitochondrial neuro-gastrointestinal encephalomyopathy syndrome, neurogenic muscle weakness, ataxia, and retinitis pigmentosa syndrome, mitochondrial depletion syndrome, Kearns-Sayre syndrome, and Leigh syndrome, Leber's hereditary optic neuropathy, Friedreich's ataxia, and multiple systemic lipomatosis. As CNS involvement is often subclinical, the CNS including the spinal cord should be investigated even in the absence of overt clinical CNS manifestations. CNS investigations comprise the history, clinical neurological examination, neuropsychological tests, electroencephalogram, cerebral computed tomography scan, and magnetic resonance imaging. A spinal tap is indicated if there is episodic or permanent impaired consciousness or in case of cognitive decline. More sophisticated methods are required if the CNS is solely affected. Treatment of CNS manifestations in MCDs is symptomatic and focused on epilepsy, headache, lactacidosis, impaired consciousness, confusion, spasticity, extrapyramidal abnormalities, or depression. Valproate, carbamazepine, corticosteroids, acetyl salicylic acid, local and volatile anesthetics should be applied with caution. Avoiding certain drugs is often more beneficial than application of established, apparently indicated drugs.
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PMID:Central nervous system manifestations of mitochondrial disorders. 1694 41

Valproate is an effective anticonvulsant. Although it is usually well tolerated, it has been associated with many neurological, hematopoietic, hepatic, and digestive system side effects. Among these side effects, hyperammonemia without clinical or laboratory evidence of hepatotoxicity is rare and is an important clinical consideration. The aim of this article was to evaluate the reasons for the unexpected symptoms observed in seven patients with epilepsy patients during valproate treatment. We evaluated seven adult patients with localization-related epilepsy who presented with different acute or subacute neurological symptoms related to valproate-induced hyperammonemic encephalopathy. Four of the seven patients had acute onset of confusion, decline in cognitive abilities, and ataxia. Two had subacute clinical symptoms, and the other patient had symptoms similar to those of acute toxicity. These unusual clinical symptoms and similar cases had not been reported in the literature before. Serum ammonia levels were elevated in all seven patients. After discontinuation of valproate, complete clinical improvement was observed within 5-10 days. On the basis of our work, we suggest that the ammonia levels of a patient who has new neurological symptoms and has been taking valproate must be checked. Clinicians should be aware that these clinical symptoms may be related to valproate-induced hyperammonemic encephalopathy. The symptoms have been observed to resolve dramatically after withdrawal of the drug.
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PMID:Different clinical manifestations of hyperammonemic encephalopathy. 1741 45


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