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Effect of carbamezapine and valproic acid on bone mineral density, IGF-I and IGFBP-3.

OBJECTIVE: To examine the effect of carbamezapine and valproate on bone mineral density (BMD), IGF-I and IGFBP-3 levels in children. METHODS: The effects of at least 2 years valproic acid and carbamazepine therapy on BMD were evaluated in a cross-sectional and retrospective study. All children were ambulatory, prepubertal, and had normal activity and nutritionally adequate diets. Ambulatory epileptic patients were divided into two groups. Thirty-three patients (group 1; 17 boys, 16 girls; mean age: 8.8 +/- 2.0 years) were treated with valproic acid and 33 patients were treated with carbamazepine (group 2; 20 boys, 13 girls; mean age: 9.7 +/- 1.6 years). The control group consisted of 22 healthy children (13 boys, 9 girls; mean age: 8.9 +/- 2.3 years), who were age- and sex-matched with the patient groups. Children with metabolic bone disease, growth and neurological impairment, signs of malnutrition, or any chronic disease were excluded from the study. RESULTS: BMD values at lumbar spine in both the carbamazepine (-1.69 +/- 0.85 mean L1-4 BMD z-scores, mean 35.5 +/- 12.8 months treatment, and 19,478.6 +/- 6,301.3 mg/kg cumulative dose) and valproic acid (-1.28 +/- 0.80 mean L1-4 BMD z-scores, mean 33.7 +/- 15.0 months treatment, and 22,852.4 +/- 12,477.4 mg/kg cumulative dose) groups were significantly lower than that of the control group (-0.23 +/- 0.87 mean L1-4 BMD z-score). Serum ALP and PTH levels were significantly higher in the carbamazepine-treated group (65.4 +/- 21.1 pg/ml, 767 +/- 267 U/l, respectively) than those of the valproic acid-treated (39.1 +/- 12.8 pg/ml, 561 +/- 166 U/l, respectively) and control groups (36.3 +/- 4.9 pg/ml, 487 +/- 82 U/l, respectively). Serum 25-hydroxyvitamin D of the carbamazepine-treated group (9.8 +/- 3.2 microg/l) was significantly lower than the other groups (15.1 +/- 3.5, 16.6 +/- 4.7 microg/l, respectively). There were eight and 13 patients with plasma intact PTH above reference values in groups 1 and 2, respectively. Valproic acid and carbamazepine therapy results in a hyperparathyroid state and altered vitamin D metabolism, respectively. CONCLUSION: BMD values at lumbar spine were significantly reduced in both carbamezapine and valproic acid treated groups. Valproic acid and carbamazepine therapy do not change IGF-I and IGFBP-3 levels. Altering the hepatic conversion of vitamin D may be the mechanism of carbamazepine-associated reduction in BMD, but the mechanism of decreased BMD in valproate therapy remains unclear.

Alkaline Phosphatase↗

Gas-chromatographic analysis for valproic acid as phenacyl esters.

We describe a novel isothermal gas-chromatographic procedure for measuring valproic acid. Plasma, with cyclohexanecarboxylic acid added as internal standard, is selectively extracted with pentane to minimize the extraction of other acidic drugs. To convert carboxylic acids to their phenacyl esters, alpha-bromoacetophenone is added to the organic extract before evaporating the solvent. These esters are relatively less volatile than the acids themselves and the extracting solvent can be removed without any loss of valproic acid or internal standard. The phenacyl esters, when chromatographed on 3% OV-17, produce sharp, well-shaped peaks and show high response for the flame ionization detector. Valproic acid is well separated from the internal standard, from reagents and plasma constituents, and from some commonly prescribed drugs that we examined. When alpha-bromo-p-nitroacetophenone is sued as the derivatizing agent, the resulting nitrophenacyl esters can be analyzed with use of a nitrogen-specific detector.

Acetophenones↗

Synergy of carbamazepine and valproic acid in affective illness: case report and review of the literature.

Carbamazepine and valproic acid are anticonvulsants with mood-stabilizing properties. Basic and clinical research suggest that these medications used together may have synergistic anticonvulsant effects. Psychotropic synergy of the combination has yet to be explored systematically. We present the case of a patient with rapid-cycling bipolar disorder studied under double-blind conditions whose hypomanias and depressions were refractory to either carbamazepine or valproic acid alone, but responded dramatically to the combination. The superior response to the combination appeared to be due to pharmacodynamic rather than pharmacokinetic effects. The clinical and theoretical aspects of the use of carbamazepine and valproic acid in combination are discussed.

Bipolar Disorder↗

Effect of long-term valproic acid administration on the efficiency of carnitine reabsorption in humans.

To elucidate the etiology of valproic acid-induced carnitine deficiency, we tested the hypothesis that long-term valproic acid administration decreases the rate of carnitine reabsorption. Thirteen healthy men participated in a 34-day protocol in which carnitine clearance was measured before and after 28 days of valproic acid administration. During valproic acid administration (days 6 to 33), plasma free and total carnitine concentrations decreased (18% and 12%, respectively, P<.05) by 16 days, but returned to pretreatment concentrations by 28 days. From day 14 to day 30, the rate of free carnitine excretion was 50% lower than at baseline (day 4, P<.05). Free and total carnitine clearance, indexed to the glomerular filtration rate, was lower after valproic acid administration (P<.01). Contrary to our hypothesis, after 28 days of valproic acid administration, the rate of carnitine reabsorption was enhanced independent of the glomerular filtration rate and filtered load. Changes in the plasma concentration, rate of excretion, and clearance were specific for carnitine and were not generalized in magnitude or direction to the other amino acids. We conclude that the kidney adapts to conserve carnitine during valproic acid administration and therefore does not cause valproic acid-induced carnitine depletion in adults.

Absorption↗

The effects of carbamazepine, valproic acid and phenobarbital on the oxidative and antioxidative balance in epileptic children.

BACKGROUND: Oxidative stress has been related in a wide variety of ways with nervous tissue. We studied the effect of antiepileptic monotherapy on serum level of total antioxidant capacity, lipid hydroperoxide, total peroxide, oxidative stress index, and individual serum antioxidants such as albumin, bilirubin and uric acid. PATIENTS AND METHODS: We studied 122 subjects including healthy controls, untreated epileptic patients and epileptic patients treated with valproic acid, carbamazepine or phenobarbital. Serum total antioxidant capacity was measured as an index of antioxidants, and total peroxide was measured as index of oxidative stress. The serum concentrations of uric acid, albumin, bilirubin and lipid hydroperoxide were monitored simultaneously. RESULTS: We found that serum total antioxidant capacity levels were significantly decreased in the untreated group compared with the controls. Serum total peroxide levels were markedly increased in the untreated and carbamazepine-treated groups compared to in the controls; and lipid hydroperoxide and oxidative stress index levels were significantly higher in the phenobarbital-treated group than in the controls. Uric acid concentrations were significantly lower in the valproic-acid-treated group than in the untreated group, and total bilirubin concentrations were higher in the untreated group than in the controls. CONCLUSION: Epileptic children exposed to oxidative stress and conventional antiepileptic drugs change the oxidative/antioxidative balance. The serum oxidant and antioxidant status of epileptic children with valproic acid monotherapy are better regulated compared with children with carbamazepine and phenobarbital monotherapy.

Anticonvulsants↗

Dissimilar effects of lithium and valproic acid on GABA and glutamine concentrations in rat cerebrospinal fluid.

1. This study compared the effects of the antimanic drugs, lithium and valproic acid, on GABA and glutamine CSF concentration and on head-shakes during hyponatremia. 2. Hyponatremic and normonatremic rats were treated with 2 mEq/kg lithium and 360 mg/kg valproic acid. Behavioral observation was conducted for 120 min after which blood and CSF collection were performed under anesthesia. 3. Peritoneal dialysis with glucose induced moderate hyponatremia and doubled glutamine CSF concentrations. Both lithium and valproic acid significantly increased GABA CSF levels in normonatremic and hyponatremic animals. Valproic acid induced head-shakes and increased CSF glutamine concentration. 4. The results suggest that both antimanic drugs have similar effects on GABA, but lithium is preferred if the increase in glutamine concentration poses a problem, either in the presence or absence of hyponatremia.

Animals↗

Acute valproic acid toxicity at therapeutic concentrations.

A previously healthy nonepileptic 11-year-old girl presented with confusion and disorientation after an acute ingestion of valproic acid. Her serum concentration of valproic acid was 39.6 mcg/ml, a range normally considered "therapeutic" in the control of seizures. She recovered without sequelae despite the subsequent attainment of higher valproic acid concentrations.

Child↗

Valproic acid and plasma levels of phenytoin.

Eight patients were treated concurrently with a constant dose of phenytoin and valproic acid for 1 year. During initial therapy with valproic acid, total plasma phenytoin levels decreased. The interaction was transient and was not observed at the end of 1 year. Total plasma phenytoin levels returned to pre-valproic-acid levels in seven patients.

Drug Interactions↗

The effects of peritoneal dialysis on the single dose and steady state pharmacokinetics of valproic acid in a uremic epileptic child.

The pharmacokinetics of valproic acid (VPA) have been studied during peritoneal dialysis in a uremic male epileptic child following a single 500 mg dose and after multiple doses over 5 months (700 mg daily) of valproic acid as the syrup. Serum level decline was biphasic in both instances with a terminal half-life of 27.2 after the single dose and 10.2 h at steady-state. Total serum clearance was 0.0236 l/h/kg after the single dose and increased to 0.0408 l/h/kg after 5 months. Free (intrinsic) serum clearances were 0.1489 and 0.1518 l/h/kg and serum free fractions were 0.224 and 0.272 respectively for the single dose and steady-state studies. Peritoneal dialysis for periods of 12 or 24 h removed an average of 4.5% of the VPA dose.

Child↗

Altered metabolic profiles of valproic acid in a patient with Reye's syndrome.

Urinary valproate metabolite and endogenous organic acid profiles in a 6-yr-old girl with Reye's syndrome were investigated by means of gas chromatography-mass spectrometry. 2-n-Propyl-3-oxovaleric acid, normally the major metabolite of valproate in man, was undetectable, while 2-n-propylglutaric acid, the end product via omega-oxidation was markedly increased. Polyunsaturated valproate was not found. Valproate-glucuronide was still found as the major metabolite. The clinical findings coupled with a greatly increased excretion of lactate and adipate was compatible with Reye's syndrome. Ketone bodies were not detectable. This case study shows that Reye's syndrome causes altered valproate metabolism, consistent with the defective mitochondrial beta-oxidation of medium chain fatty acids, and suggests that valproic acid should not be used in the treatment of seizures in patients with this syndrome.

Biotransformation↗

Excipients in valproic acid syrup may cause diarrhea: a case report.

A 5-year-old child receiving valproic acid syrup for seizure control developed diarrhea probably from the excipient ingredients. Each 5 mL of valproic acid syrup contains sucrose 3 g, glycerin 0.75 g, and sorbitol 0.75 g, providing daily amounts of 36, 9, and 9 g of sucrose, glycerin, and sorbitol, respectively. The diarrhea resolved when the child was switched to another valproic acid product. Clinicians should be aware of potential problems that may occur from excipient ingredients in pharmaceutical products when evaluating adverse effects of medications.

Child, Preschool↗

Modulation of angiogenesis-related protein synthesis by valproic acid.

Recent studies have attested to the antiangiogenic effects of HDAC inhibitors on solid human tumors. The HDAC inhibitor butyrate has been reported to impair tumor-cell-induced angiogenesis. However, due to its poor bioavailability in vivo, the therapeutic use of butyrate is limited. On the other hand, valproic acid has inhibitory effects on carcinoma cells, is known to be well tolerated, and has an excellent bioavailability. We therefore set out to investigate whether the HDAC inhibitor valproic acid also impairs angiogenesis. Our findings indicate that valproic acid represses the relevant angiogenic factors VEGF and FGF in Caco-2 cells. Both, protein expression as well as mRNA levels of VEGF, were reduced to a similar degree. Suppression of ubiquitin-proteasome activity could be a possible reason for valproic acid effects on regulatory angiogenesis proteins. These results suggest that the HDAC inhibitor valproic acid could become a valuable new addition in the attempt to develop alternative therapeutic approaches in the treatment of colon carcinomas.

Blotting, Western↗

[The risk of defects in the neural tube caused by valproic acid and carbamazepine].

OBJECTIVE: To determine the risk, if any, of carbamazepine and valproic acid use on the foetus with respect to neural tube defects. MATERIALS AND METHODS: Databases such as MEDLINE, EMBASE, SCISEARCH, The Cochrane Library and LILACS were consulted to have access to published literature from January 1966 to September 2004. All articles published in English and Spanish were considered. A manual review of the references presented in each produced article was done in order to identify the articles that the electronic search may have not found itself. However, articles which seemed ambiguous as to the title and/or abstract were completely analyzed to establish their relevance. Studies that examined the effects of systematic exposure to carbamazepine or valproic acid during pregnancy and that assessed neural tube defects in the infants were eligible. The data was extracted in the form of 2 x 2 tables. The odds ratio (OR), relative risk (RR) and 95% confidence interval (CI) was calculated for each of the studies. RESULTS: The pooled relative risk of neural tube defects among the exposed to valproic acid was 0.61 (95% CI: 0.06-6.72). The risk among the exposed to carbamazepine was 1.10 (95% CI: 0.16-7-75). CONCLUSIONS: Due to the methodologic limitations of most of the studies where the data was insufficient, only three studies could be included in the meta-analysis. There is not enough evidence to establish the risk raised in the objective of the study.

Anticonvulsants↗

Antineoplastic effects of the DNA methylation inhibitor hydralazine and the histone deacetylase inhibitor valproic acid in cancer cell lines.

BACKGROUND: Among the epigenetic alterations occurring in cancer, DNA hypermethylation and histone hypoacetylation are the focus of intense research because their pharmacological inhibition has shown to produce antineoplastic activity in a variety of experimental models. The objective of this study was to evaluate the combined antineoplastic effect of the DNA methylation inhibitor hydralazine and the histone deacetylase inhibitor valproic acid in a panel of cancer cell lines. RESULTS: Hydralazine showed no growth inhibitory effect on cervical, colon, breast, sarcoma, glioma, and head & neck cancer cell lines when used alone. On the contrary, valproic acid showed a strong growth inhibitory effect that is potentiated by hydralazine in some cell lines. Individually, hydralazine and valproic acid displayed distinctive effects upon global gene over-expression but the number of genes over-expressed increased when cells were treated with the combination. Treatment of HeLa cells with hydralazine and valproic acid lead to an increase in the cytotoxicity of gemcitabine, cisplatin and adriamycin. A higher antitumor effect of adriamycin was observed in mice xenografted with human fibrosarcoma cells when the animals were co-treated with hydralazine and valproic acid. CONCLUSION: Hydralazine and valproic acid, two widely used drugs for cardiovascular and neurological conditions respectively have promising antineoplastic effects when used concurrently and may increase the antitumor efficacy of current cytotoxic agents.

Journal Article↗

Pharmacokinetics of valproic acid in young and elderly subjects.

The disposition of valproic acid was studied following single dose intravenous administration in seven young male volunteers aged 20-35 years and six elderly male in-patients aged 75-87 years. Following administration of 400 mg sodium valproate, blood samples were collected for 48 h and valproic acid concentrations analysed by enzymatic immunoassay. The median elimination half-life was 7.2 h in the young subjects but 14.9 h in the elderly patients (P less than 0.01). However, clearance did not differ significantly between groups, the values for young and old being 0.69 and 0.58 1/h respectively. The prolonged half-life resulted from a greater volume of distribution in the elderly. The median values (1/kg) for young and old were 0.13 and 0.19 respectively (P less than 0.01). These pharmacokinetic changes are unlikely to be of clinical importance.

Adult↗

Lipids, lipoproteins, apolipoproteins, selected trace elements and minerals in the serum of children on valproic acid monotherapy.

We evaluated the serum levels of lipids, lipoproteins, apolipoproteins, along with a number of minerals and trace elements such as Ca, Mg, Cu and Zn in a group of children after 6 months of valproic acid monotherapy. Thirty patients with seizures, mean age, 9.8+/-2.6 years and 79 healthy children (controls), mean age, 10.9+/-3.2 years, formed the two styd groups. The patient group was treated with valproic acid (27.9+/-14.8 mg/kg/24 hr). Patients underwent clinical and laboratory evaluations including liver function tests, NH3, lipid, mineral and selected trace element levels before and after six months on valproic acid treatment, whereas controls only one evaluation. Liver function data and NH3 levels were found to be elevated in the group of patients, whereas albumin level was reduced. Triglycerides, total cholesterol, HDL-C, apolipoprotein (ApoA)-1, Apo B and Ca concentrations were found relative to control values, LDL-C, VLDL-C, Mg, Cu, Zn, were measured significantly altered (P<0.0001) compared to controls. The ratios ApoA-1/ApoB, HDL-C/ApoA-1, LDL-C/Apo B, which were closely related to the size of LDL particles, where correlated with Zn/Cu (P<0.001). Serum lipid profile, especially LDL size, indirectly evaluated for the first time and metal levels were found to be significantly changed, after six months on valproic acid monotherapy, suggesting a possible risk of developing coronary heart disease. Since valproic acid is a long-term treatment, it could be recommended that the incorporation of measurements of lipids, lipoproteins, apolipoproteins and trace elements in the "follow up" laboratory testing could be a preventive measure.

Apolipoproteins↗

Valproic acid in ultra-rapid cycling: a case report.

Valproic acid has been proven to be efficient in the treatment of bipolar affective disorders as an adjunctive agent to lithium and carbamazepine. Recently, its efficacy in rapid cycling states has attracted interest. We present the case of a male patient with bipolar affective disorder who developed an extreme state of ultra-rapid cycling (48-h cycles). Only the addition of valproic acid therapy to prior lithium treatment succeeded in curtailing the ultra-rapid cycling. Several issues regarding ultra-rapid cycling and valproate's efficacy in bipolar disorder are discussed.

Bipolar Disorder↗

Effect of antiepileptic drugs valproic acid, carbamazepine and ethosuccimide on exploratory behaviour in mice.

Valproic acid in 100, 200 and 400 mg/kg doses produced a significant dose dependent decrease in exploratory behaviour, tested as number of head dips on the hole board. In the open field test, control mice entered less number of peripheral squares and more number of central squares on day 4 as compared to day 1 of the test. In the lower doses (100 and 200 mg/kg) valproic acid increased central square entries on day 1 with significant decrease by all doses on subsequent days indicating inhibition of exploratory behaviour. However, in peripheral square entry they followed the same pattern as control mice. Neither carbamazepine (10 and 20 mg/kg) nor ethosuccimide (100 and 200 mg/kg) affected exploratory behaviour in either the hole board or open field test.

Analysis of Variance↗