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PubMed1994

Valproate for treatment of chronic central pain after spinal cord injury. A double-blind cross-over study.

Chronic central pain is a frequent complication after spinal cord injury. Anticonvulsant drugs, among them valproate, have been recommended for treatment. In this paper we conducted a double-blind, cross-over study comparing valproate and placebo for severe chronic central pain. During the study, serum concentration of valproate, pain and side effects were registered and the dose was adjusted according to these. No significant analgesic effects of valproate could be demonstrated although serum concentration and dose reached a high level. Few studies of pain following spinal cord injury exist and we recommend that further studies be performed.

Adolescent↗

PubMed2006

The anticonvulsants lamotrigine, riluzole, and valproate differentially regulate AMPA receptor membrane localization: relationship to clinical effects in mood disorders.

A growing body of data suggests that the glutamatergic system may be involved in the pathophysiology and treatment of severe mood disorders. Chronic treatment with the antimanic agents, lithium and valproate, resulted in reduced synaptic expression of the AMPA(-amino-3-hydroxy-5-methylisoxazole-4-propionic acid) receptor subunit GluR1 in the hippocampus, while treatment with an antidepressant (imipramine) enhanced the synaptic expression of GluR1. The anticonvulsants, lamotrigine (6-(2,3-dichlorophenyl)-1,2,4-triazine-3,5-diamine) and riluzole (2-amino-6-trifluoromethoxybenzothiazole), have been demonstrated to have efficacy in the depressive phase of bipolar disorder. We therefore sought to determine the role of these anticonvulsants, compared to that of the predominantly antimanic anticonvulsant valproate, on AMPA receptor localization. We found that the agents with a predominantly antidepressant profile, namely lamotrigine and riluzole, significantly enhanced the surface expression of GluR1 and GluR2 in a time- and dose-dependent manner in cultured hippocampal neurons. By contrast, the predominantly antimanic agent, valproate, significantly reduced surface expression of GluR1 and GluR2. Concomitant with the GluR1 and GluR2 changes, the peak value of depolarized membrane potential evoked by AMPA was significantly higher in lamotrigine- and riluzole-treated neurons, supporting the surface receptor changes. Phosphorylation of GluR1 at the PKA (cAMP-dependent protein kinase) site (S845) was enhanced in both lamotrigine- and riluzole-treated hippocampal neurons, but reduced in valproate-treated neurons. In addition, lamotrigine and riluzole, as well as the traditional antidepressant imipramine, also increased GluR1 phosphorylation at GluR1 (S845) in the hippocampus after chronic in vivo treatment. Our findings suggest that regulation of GluR1/2 surface levels and function may be responsible for the different clinical profile of anticonvulsants (antimanic or antidepressant), and may suggest avenues for the development of novel therapeutics for these illnesses.

Animals↗

PubMed1983

Inhibition of ureagenesis by valproate in rat hepatocytes. Role of N-acetylglutamate and acetyl-CoA.

Valproate (0.5-5 mM) strongly inhibited urea synthesis in isolated rat hepatocytes incubated with 10 mM-alanine and 3 mM-ornithine. Valproate at the same concentrations markedly decreased concentrations of N-acetylglutamate, an essential activator of carbamoyl-phosphate synthetase I (EC 6.3.4.16), in parallel with the inhibition of urea synthesis by valproate. This compound also lowered the cellular concentration of acetyl-CoA, a substrate of N-acetylglutamate synthase (EC 2.3.1.1); glutamate, aspartate and citrulline were similarly decreased. Valproate in a dose up to 2 mM did not significantly affect the cellular concentration of ATP and had no direct effect on N-acetylglutamate synthesis, carbamoyl-phosphate synthetase I and ornithine transcarbamoylase (EC 2.1.3.3) activities.

Acetyl Coenzyme A↗

PubMed2001

Sodium valproate-induced cutaneous pseudolymphoma followed by recurrence with carbamazepine.

We report a patient with a sodium valproate-induced cutaneous pseudolymphoma, presenting with an erythematous papule, histologically mimicking a non-epidermotropic T-cell lymphoma. Polymerase chain reaction study of the skin biopsy revealed monoclonal rearrangement of the T-cell receptor gamma gene. Withdrawal of sodium valproate was followed by regression of the lesion, but 5 months after substitution by carbamazepine, two further papules appeared, with similar histological features and a T-cell clone identical to the initial one. Carbamazepine was stopped and the lesions disappeared without relapse over a 4-year follow-up. Sodium valproate is very rarely responsible for a hypersensitivity syndrome, and our case is the first report of sodium valproate-induced cutaneous pseudolymphoma. The recurrence with carbamazepine may be due to a common effect on T-cell lymphocyte function. The return of the same monoclonal population shows that the recurrence of monoclonal T cells may be observed in benign conditions and is not an exclusive hallmark of cutaneous lymphoma.

Adult↗

PubMed2000

Expression of yeast INM1 encoding inositol monophosphatase is regulated by inositol, carbon source and growth stage and is decreased by lithium and valproate.

Inositol monophosphatase plays a vital role in the de novo biosynthesis of inositol and in the phosphoinositide second messenger signalling pathway. We cloned the Saccharomyces cerevisiae open reading frame (ORF) YHR046c (termed INM1), which encodes inositol monophosphatase, characterized the protein Inm1p and analysed expression of the INM1 gene. INM1 was expressed in bacteria under the control of the lacZ promoter. The purified protein has inositol monophosphatase activity that is inhibited by the antibipolar drug lithium, but not valproate. In the inm1Delta:URA3 null mutant, inositol monophosphatase activity was reduced but not eliminated. The disruption had little effect on growth in the presence of lithium or valproate and no effect on growth in the absence of inositol. To characterize the regulation of INM1, we examined the effects of inositol, carbon source, growth phase, and the antibipolar drugs lithium and valproate on INM1 expression using an INM1-lacZ reporter gene. Unlike all other phospholipid biosynthetic enzyme-encoding genes studied, which contain the UASINO regulatory element, INM1 expression is increased in the presence of inositol. In addition, INM1 expression was repressed during growth in glycerol and derepressed as glucose-grown cells entered stationary. Both lithium and valproate, which cause a decrease in intracellular inositol, effect a decrease in INM1 expression. A model is presented to account for regulation of INM1 expression.

Amino Acid Sequence↗

PubMed1999

Different mechanisms of protection against apoptosis by valproate and Li+.

Acute treatment with valproate and Li+ was found to protect cultured cerebellar granule cells against apoptosis induced by low K+ (5 mM). Because the protection was unaffected by MK801 (N-methyl-D-aspartate receptor inhibitor), an increase in glutamate release cannot be responsible for the observed neuroprotection. Insulin also protects against low-K+-induced apoptosis of cerebellar granule cells. This protection is totally dependent on LY294002 (a phosphatidylinositol 3-kinase inhibitor). These results suggest a role for phosphatidylinositol 3-kinase in the neuroprotection induced by insulin. Likewise, and in contrast with the results observed with Li+, the protection induced by valproate is also dependent on insulin and LY294002. Moreover, valproate (a branched-chain fatty acid) does not change the plasma membrane microviscosity under physiological conditions. These results suggest that valproate protects against low-K+-induced apoptosis by acting in the phosphatidylinositol 3-kinase/protein kinase B pathway. The protection by Li+ is independent of this transduction pathway.

Animals↗

PubMed2002

Visual cortex excitability in migraine before and after valproate prophylaxis: a pilot study using TMS.

We examined the effect of standard migraine prophylaxis with sodium valproate on repeated measures of occipital excitability using transcranial magnetic stimulation (TMS). We predicted that, comparing pre- and post-treatment assessments, a reduction in clinical migraine parameters would be paralleled by a decrease in excitability measurements.A total of 31 migraine patients enrolled in the study, for assessment prior to and 1 month after commencement of sodium valproate prophylaxis. At each assessment, we used a standardized protocol to stimulate the occipital cortex with a 90-mm circular (coil A) and 70 mm figure-of-eight (coil B) coil. We recorded the threshold stimulation intensity at which subjects just perceived phosphenes. Subjects kept detailed records of headache parameters 1 month before and also during the study period. Valproate therapy significantly improved headache indexes, as expected. In MA subjects assessed with coil B, phosphene thresholds were significantly higher post-treatment than pre-treatment, but those for MO did not change. Modest correlations were observed in MA patients between increase in phosphene threshold and decrease in headache index. Although preliminary, the findings with coil B lend some support to the notion that effective migraine prophylaxis may be achieved through lowering cortical excitability by gamma-aminobutyric acid (GABA)-ergic intervention. Further investigation of the effect of sodium valproate or other similarly acting substances on cortical excitability in migraine is warranted.

Anticonvulsants↗

PubMed1997

Possible mechanisms of valproate in migraine prophylaxis.

Valproate has been shown to be an effective prophylactic treatment in migraine. Investigation of the mechanism of its antimigraine action is difficult due to the broad range of its biochemical effects and the complex nature of migraine pathophysiology. Valproate increases brain GABA levels and, in doing so, may suppress migraine-related events in the cortex, perivascular parasympathetics or trigeminal nucleus caudalis. There is experimental evidence that it suppresses neurogenic inflammation and directly attenuates nociceptive neurotransmission. In addition, valproate reportedly alters levels of excitatory and inhibitory neurotransmitters and exerts direct effects on neuronal membranes in vitro. Valproate's observed effect may ultimately result from a combination of actions at different loci.

Animals↗

PubMed2003

Combined therapy for migraine prevention? Clinical experience with a beta-blocker plus sodium valproate in 52 resistant migraine patients.

The aim was to explore whether combining a beta-blocker and sodium valproate could lead to an advantage in efficacy in patients with migraine previously resistant to the two medications in monotherapy. Fifty-two patients (43 women) with a history of episodic migraine with or without aura, and previously unresponsive to beta-blockers and sodium valproate in monotherapy, were treated with a combination of propranolol or nadolol and sodium valproate in an open-label fashion. Eight patients (15%) discontinued due to adverse events. Fifteen (29%) did not respond. The remaining 29 cases (56%) showed response (> 50% reduction in migraine days). The response was excellent in nine (17%). From this open trial, combination therapy with a beta-blocker and sodium valproate appears to be a good migraine preventative in some previously resistant migraine cases. Controlled trials are now necessary to determine the true advantage in efficacy of this combination in difficult to treat migraineurs.

Adrenergic beta-Antagonists↗

PubMed2002

Intravenous valproate sodium in the treatment of daily headache.

BACKGROUND: Treatment of chronic daily headache/transformed migraine is challenging, especially when it is complicated by overuse of analgesics, triptans, or both. One common approach involves the use of repetitive intravenous dihydroergotamine. We investigated the use of intravenous valproate sodium in the treatment of chronic daily headache/transformed migraine in patients who had contraindications to the use of or had failed treatment with dihydroergotamine. METHODS: We administered intravenous valproate sodium (Depacon) to patients with chronic daily headache/transformed migraine (loading dose 15 mg/kg, followed by 5 mg/kg every 8 hours). All analgesics and triptans were discontinued prior to treatment with divalproex sodium, and preventative medications for migraine were begun or continued. All patients received instruction in behavioral modification and the proper use of analgesics and triptans. RESULTS: Improvement in headache was reported by 80% of the patients treated, and valproate sodium was tolerated well by most. CONCLUSION: Intravenous valproate sodium may be of assistance in the initial management of patients with chronic daily headache/transformed migraine and analgesic/triptan overuse, especially when dihydroergotamine is ineffective or contraindicated.

Adolescent↗

PubMed2000

Current perception thresholds of epileptic patients treated with valproate.

We investigated the current perception threshold (CPT) of epileptic patients treated with valproate. The CPTs at frequencies of 5 Hz, 250 Hz and 2000 Hz in the control group of patients were 198.9 +/- 15.8, 62.0 +/- 18.9 and 35.3 +/- 15.8, respectively. The CPTs at 5 Hz, 250 Hz and 2000 Hz in the epileptic group of patients were 350.6 +/- 61.3, 338.6 +/- 64.3 and 193.2 +/- 21.1, respectively. The CPTs at 5 Hz, 250 Hz and 2000 Hz in the epileptic group were significantly higher than those of the control group. We measured the CPTs for 6 months after the administration of valproate in three patients with traumatic epilepsy. Their CPTs were higher than that of the epileptic group. The CPTs at 5 Hz, 250 Hz and 2000 Hz reached a maximum 4 weeks after the administration of valproate for two of these patients and in 6 weeks for the other patient. When the administration of valproate to a patient was stopped, CPTs decreased.

Adolescent↗

PubMed2002

Visual functions in epilepsy patients on valproate monotherapy.

Gamma-aminobutyric acid-induced ion transport changes in the retinal pigment epithelium are described. Valproate acts as an inhibitor of gamma-aminobutyric acid transaminase. The purpose of this study was to investigate whether early visual impairment is related to valproate in patients with and without visual symptoms. Thirty-two patients, presenting with a history of seizures currently being treated with valproate, were included in the study. A complete clinical neuroophthalmologic examination was performed, including electroretinogram and visual field test. The electroretinogram parameters of epileptic patients were compared with those of 28 age- and sex-matched healthy volunteers. There was no significant difference in ERG parameters between the two groups. The visual field and visual acuity of all patients were within normal limits. When valproate is not used in conjunction with other antiepileptic drugs and serum levels are within therapeutic levels, it does not cause electrophysiologically detectable retinal dysfunction or any functional defect in visual perception that can be determined clinically.

Adolescent↗

PubMed2000

[Effectiveness, safety and practicality of delayed-release minitablets of valproate in bipolar affective disorders].

UNLABELLED: Valproate has recently emerged as a drug of first choice in treating acute mania because of its efficacy and relative safety. It can be administered as an intravenous, oral non-sustained release or oral sustained release loading therapy. A new sustained release formulation of valproate consists of "mini-tablets" with the possible advantage of a less problematic and more reliable administration of the drug. We report on eleven patients with an acute manic exacerbation who were investigated for sufficient control of manic symptoms and the duration of building up and maintaining sufficient blood levels of valproate in once/d versus twice/d administration of valproate delayed release mini-tablets (VPA mrt.). Acute and prophylactic effectiveness in mania were rated with the Young-Mania Rating Scale (YMRS), respectively the Global Clinical Impression Scale for Bipolar Disorder (CGI-BP). RESULTS: Within a short period of time sufficient blood levels in both groups (once/d versus twice/d administration) were built up. Seven of eleven patients were responders according to a reduction of 50% of the YMRS. In respect of prophylactic treatment all of the ten patients showed satisfactory results and no re-exacerbation of manic symptoms or depression.

Adult↗

PubMed2000

Valproate and the symptomatic treatment of schizophrenia spectrum patients.

Valproate is currently one of the most frequently prescribed drugs in schizophrenia spectrum disorders. However, surprisingly little is known from controlled studies. Also, no review articles are available. Here, we summarize basic and clinical research on valproate and its application for treatment in schizophrenia spectrum disorders. The molecular and physiological effects of valproate are outlined. It is discussed how the effects of valproate on the cellular level involving serotonin, GABA, glutamate, sodium-channels, membrane fluidity and RNA-expression may account for its clinical effect in schizophrenia spectrum patients. The target symptoms are a reduction of psychomotor agitation and aggression, possibly reflecting a drug effect on temporal lobe pathology, which is considered to be involved in the etiology of schizophrenic illness.

Clinical Trials as Topic↗

PubMed2006

Effects of sodium valproate on renal functions in rats.

In recent years, it has been reported that sodium valproate occasionally can cause renal tubular impairment. This study was designed to demonstrate the renal tubular and glomerular functions in rats given sodium valproate as monotherapy, as well as to determine any reversibility of dysfunctions. Female rats were randomly allocated to three groups: group 1 received sodium valproate 500 mg/kg/d intraperitoneal for six weeks; after the same injection period, group 2 was housed for another six weeks, after which laboratory investigations were completed; and group 3 served as a control group made up of 20 healthy rats living in same condition without any treatment. Serum ALT, total protein, uric acid, ALP, phosphorus, sodium levels, and urine Ca/cr ratio were significantly different between groups 1 and 3 (p < 0.025), but this difference was not seen between groups 2 and 3. On the other hand, other parameters such as TRP, Ccr, NAG, and MDA were not significantly different among the three groups ( p > 0.025) These results suggest that SV does not have a significant dose- or time-related side effect on renal functions. Minor biochemical dysfunctions related to long-term sodium valproate therapy is reversible, and the minimal renal fibrosis that showed histopathologically is not clinically important. The renal tissues of rats are known to show similar metabolic and histological patterns with human renal tissues. No renal dysfunction was expected in humans because there were no clinically statistically significant renal side effects in this study.

Alanine Transaminase↗

PubMed2004

Lithium and valproate protect against dextro-amphetamine induced brain choline concentration changes in bipolar disorder patients.

BACKGROUND: Lithium may affect brain choline concentrations, and this effect has been proposed to potentially explain its clinical efficacy. Since dextro-amphetamine is a useful human model of mania, we were interested in determining firstly whether dextro-amphetamine would alter brain choline concentrations, and secondly to determine if lithium would protect against any such changes in bipolar patients. In addition, we wanted to determine if valproate would also have any effects upon choline levels. METHODS: Healthy controls (n=18) were compared with euthymic Bipolar Disorder patients (Type I and Type II) who were taking lithium (n=14) or valproate (n=11). We utilized (1)H-magnetic resonance spectroscopy ((1)H-MRS) in a 3.0T scanner to examine brain choline/phosphocholine+creatine (Cho/Cr) ratios. Changes in this ratio were measured to determine any changes in choline concentrations in the temporal lobe. RESULTS: The results showed that administration of dextro-amphetamine decreased the Cho/Cr ratios. In contrast, in both the lithium-treated and valproate-treated patients this decrease was not seen; this attenuation in the change in Cho/Cr ratio changes was statistically significant. It should be noted that Cho/Cr ratios were significantly higher at baseline in the controls compared to both groups of patients, which may have influenced the results. CONCLUSIONS: These findings are the first to examine the effects of dextro-amphetamine on brain choline concentrations. They show that while in controls dextro-amphetamine decreases choline concentrations, lithium and valproate both appear to protect against this effect in bipolar patients. However, as brain ratios were measured rather than the absolute concentration of choline, and these ratios were lowered in patients at baseline, these results must be regarded as preliminary and require replication in future studies.

Antipsychotic Agents↗

PubMed1998

Increased plasma valproate concentrations when coadministered with guanfacine.

A preliminary clinical observation suggests the possibility of changes in valproate level when coadministered with guanfacine. Two pediatric inpatients (8 and 9 years of age) were treated with valproic acid and guanfacine concurrently. In one child, when guanfacine was tapered and discontinued, the plasma valproate concentration decreased by 41% from 128 microg/mL to 76 microg/mL. In the other case, studied in an ABA design, the child exhibited a rapid increase in plasma valproate levels while guanfacine was administered. It is proposed that guanfacine may affect the pharmacokinetics of valproic acid and lead to a significant increase in valproate plasma levels when used concurrently with this agent. The mechanism of this proposed interaction may involve drug-drug competition at the level of hepatic glucuronidation (conjugation), although shifts in protein binding cannot be ruled out.

Adrenergic alpha-Agonists↗

PubMed1986

Interaction between thiopentone and sodium valproate. An in vitro and in vivo study.

The effect of sodium valproate on the binding of thiopentone to serum protein was studied in vitro. In the absence of valproate the unbound fraction of thiopentone was 15.2 +/- 0.64%, but with concentrations of valproic acid in excess of the therapeutic range, it increased to 22.42 +/- 1.65%. Scatchard plots for thiopentone in the absence and presence of valproate were investigated also. The barbiturate was bound by one group of binding sites with the association constant, Ka = 2.81 X 10(3) litre mol-1 and the number of binding sites (n) = 2.3. There was a marked decrease in this association constant in the presence of valproic acid (Ka = 1.82 X 10(3) litre mol-1), but without significant change in the number of binding sites (n = 2.13). Additionally, the effect of administration of sodium valproate i.v. on thiopentone anaesthesia was examined in rabbits. The recovery time from thiopentone was markedly longer in the presence of the anticonvulsant drug (17.0 min v. 37.1 min).

Anesthesia Recovery Period↗