Valproate and palmitate binding to serum albumin in valproate-treated patients. Relation to obesity

Effect of Sodium Valproate on Weight, Body Mass Index, Uric Acid, Vitamin D3, Blood Insulin, and Serum Lipid Profile in Children

Introduction:

Due to the high prevalence of epilepsy and the use of sodium valproate as an antiepileptic drug by these patients, accurate recognition of its side effects and its effects on serum lipids profile, liver enzymes, uric acid level, and thyroid function tests, especially in cases that need long-term treatment seems essential. This study aimed to evaluate the effects of sodium valproate on weight, body mass index (BMI), vitamin D3, blood insulin, uric acid level, and serum lipids profile in children with newly diagnosed epilepsy.

Materials and Methods:

This prospective study was performed on 30 children between 3 and 8 years of age who suffered from newly diagnosed epilepsy and received sodium valproate as monotherapy. Data including demographic information (age, sex, height, weight, and waist and hip circumference of children), as well as clinical characteristics, such as liver enzymes (ALT, AST, ALK-P), serum lipids level (TG, TC, HDL-C, LDL-C), thyroid tests (TSH, T4), fasting blood sugar (FBS), uric acid level, 25 OH Vitamin D3 (Vit-D3), and blood insulin level of children before and six months after the consumption of sodium valproate, were examined.

Results:

The mean weight of children before and six months after the start of sodium valproate treatment was 18.54±2.99 and 21.13±3.93 (kg), respectively. This difference was statistically significant (P=0.005). Also, the mean weight Z-score of children before and after taking sodium valproate was -2.497 and -2.293, respectively, which was statistically significant too. In addition to weight gain, there was also a significant increase in the abdominal and hip circumference of children after taking valproate, whereas the increase in mean BMI before and after valproate administration was not statistically significant (P=0.114). However, mean weight gain, as well as the increase in the waist and hip circumference, had no relationship with gender (P> 0.05). Also, sodium valproate significantly increased the ALT level (P=0.046). Moreover, sodium valproate did not affect other liver function markers (AST), thyroid hormones (TSH, T4), fasting blood sugar (FBS), uric acid level, 25 OH Vit-D3, and the children's blood insulin levels (P> 0.05).

Conclusion:

According to the findings of this study, it can be concluded that sodium valproate is a good drug for children between 3 and 8 years of age, but it should be noted that taking this drug increases the chance of obesity in children. The main side effect of this drug is weight gain. Due to the significant increase in ALT enzyme, as observed in this study, it is recommended to check liver enzymes before, one, and six months after starting treatment as it can prevent the irreversible permanent side effects of this drug.

Does valproate therapy in epileptic patients contribute to changing atherosclerosis risk factors? The role of lipids and free fatty acids

BACKGROUND

We aimed to demonstrate the relationship between the valproate (VPA) treatment versus lipid and serum free fatty acids (FFAs) profiles to be the potential atherosclerosis risk factor in epileptic patients.

METHODS

Fasting blood samples were taken from 21 adult VPA-treated patients and 21 controls. The profiles of lipids, FFAs, clinical parameters and body mass index (BMI) were evaluated.

RESULTS

No significant differences between the study group and controls were found for any of the studied parameters. However, significant differences in the total cholesterol (CHOL), low-density-lipoprotein cholesterol (LDL), triglycerides, the CHOL/HDL (high-density-lipoprotein cholesterol) ratio, and Atherogenic Index of Plasma were observed for overweight patients when compared to those of normal weight. Patients with uncontrolled epilepsy tended to have significantly lower palmitic acid level than seizure-free patients. Oleic acid was found to be positively correlated with VPA concentration for patients with uncontrolled epilepsy, and with the dose corrected VPA concentration for all the patients. The acid was however negatively correlated with stearic acid for both the controls and the patients with uncontrolled epilepsy. PLS method revealed CHOL, LDL, triglycerides and myristic acid to be positively interrelated for the whole group under the study, whereas these parameters were found to be negatively correlated with VPA concentration, and positively with BMI. Furthermore, high sensitivity C-reactive protein was found to be negatively correlated with palmitic acid levels.

CONCLUSION

Overweight VPA-treated patients are exposed to higher risk of atherosclerosis. Alterations in FFAs are likely to depend on seizures control, and on VPA levels.

Weight gain and insulin resistance in children treated with valproate: the influence of time

This study was undertaken in 2 parts to investigate the relationship between body size and insulin resistance during treatment with valproic acid in children. The cross-sectional part revealed differences in terms of body size and homeostasis model assessment of insulin resistance, which were higher in the group on medication. The longitudinal part showed a major increase in body size and insulin resistance during the first year of therapy. There was a subsequent decrease in insulin resistance in association with the rise of body size, however with a trend to level off. These results might be helpful to enhance the knowledge of valproic acid action on both insulin resistance and weight gain, allowing to plan appropriate approach for the prevention of the consequences of the treatment with valproic acid.

Metabolic alterations during valproic acid treatment: a prospective study

We prospectively examined the effects of valproic acid on the endocrine system and metabolic variables in epileptic children. Patients with newly diagnosed idiopathic epilepsy were included in the study. Laboratory and clinical variables were assessed before and after 6 and 12 months of treatment. In total, 30 patients (mean age, 8.6 +/- 4.4 years S.D.) were investigated. Body mass index and body mass index standard deviation scores of patients increased significantly during treatment. Although there was no statistical significance regarding fasting glucose, serum insulin, triglyceride, and high-density lipoprotein cholesterol levels and the insulin resistance index, a statistically significant increase in total and low-density lipoprotein cholesterol levels had occurred after 12 months of valproic acid treatment. At the end of the study period, four patients were obese, and six patients were overweight. There was a significant correlation between serum levels of valproic acid and body mass index at month 6 of treatment. There was no significant change in androgen hormone levels during treatment in the prepubertal group. Body mass index and body mass index standard deviation scores increased during the first 6 months of valproic acid treatment. Patients treated with valproic acid should be regularly followed for obesity.

States of serum leptin and insulin in children with epilepsy: risk predictors of weight gain

BACKGROUND AND OBJECTIVES

Weight gain is an adverse metabolic effect in some children with epilepsy. The studies done to detect the effect of antiepileptic drugs and weight homeostatic hormones, insulin and leptin, were limited and controversial.

MATERIALS AND METHODS

We evaluated the serum leptin and insulin as predictors of weight gain in children receiving long-term treatment with valproate (VPA), carbamazepine (CBZ), lamotrigine (LTG). This study included 90 patients (treated: 70; untreated: 20). Serum lipid profile, insulin and leptin were measured.

RESULTS

BMI, serum leptin and insulin were significantly elevated in VPA compared with controls, untreated patients and those treated with CBZ, LTG and combined therapy with LTG. Girls on VPA had higher BMI and leptin levels than boys. With VPA, serum insulin was correlated with BMI (r=0.625, p<0.01), leptin (r=0.823, p<0.001), treatment duration (r=0.775, p<0.01) and VPA dose (r=0.975, p<0.0001). Serum leptin was correlated with age (r=0.980, p<0.0001), BMI (r=0.704, p<0.01), serum insulin (r=0.823, p<0.001), LDL-c (r=0.630, p<0.01), HDL-c (r=-0.880, p<0.001), treatment duration (r=0.770, p<0.01) and VPA dose (r=0.970, p<0.001). BMI is correlated with serum insulin, leptin, LDL-c (r=0.835, p<0.001) and HDL-c (r=-0.955, p<0.0001).

CONCLUSION

Hyperinsulinemia and hyperleptinemia are common with VPA and marked among epileptic children who gained weight suggesting states of insulin and leptin resistances. These alterations were not demonstrated with CBZ or LTG. The relationship between VPA, leptin and weight seems to be gender specific. Serum leptin may serve as a sensitive parameter for weight gain and reduction with intervention programs during follow-up of girls with epilepsy.

Body Mass Index and Serum Lipid Changes During Treatment with Valproic Acid in Children with Epilepsy

BACKGROUND

Valproic acid is the drug of choice for a wide variety of epileptic seizures and syndromes because of its broad spectrum of activity and because, in most patients, it is well tolerated. Although weight gain is a well-known adverse effect of valproic acid therapy, only a few studies have addressed weight gain associated with it in children aged 2–8 years.

OBJECTIVE

To evaluate valproic acid–associated changes in the body mass index (BMI) z-scores and to assess changes in serum triglyceride, cholesterol, and fasting glucose levels in young children receiving valproic acid treatment.

METHODS

Eighty-seven patients (39 females, 48 males) receiving valproic acid therapy for at least 3 months were included in the retrospective longitudinal study. Mean ± SD age at initiation of therapy was 4.8 ± 0.8 years. Changes in BMI z-scores as well as serum triglyceride, total cholesterol, and fasting glucose levels were evaluated as continuous variables and analyzed by longitudinal methods for all patients.

RESULTS

The average change from baseline in BMI z-scores was 0.80 (p = 0.001) at 3.1 years of follow-up. No significant change in triglyceride, cholesterol, and serum fasting glucose levels was observed over the same period. The percentage of overweight children at baseline was 6.9% and rose to 16% by the final visit (p = 0.081).

CONCLUSIONS

Valproic acid–associated weight gain may occur in young children. However, only 16% of patients were categorized as overweight at the end of the study; this percentage overlaps the percentage of overweight healthy young Italian children. The BMI z-scores significantly increased during the first 16 months of therapy, then appeared to level off. These observations may influence clinical practice and decision-making regarding suspending the drug due to weight gain in children in whom seizure control has been achieved. A For Our Patients summary of this article is available at www.ForOurPatients.info

Polycystic ovary syndrome in women using valproate: a review

Valproate (VPA) is a highly effective drug successfully employed in several neuropsychiatric diseases. In the last 15 years, an increased prevalence of polycystic ovary syndrome (PCOS) associated with VPA use has been reported in both women with epilepsy and women with bipolar disorders. However, data on this subject are contrasting and it is possible that different factors might play a role in the development of PCOS in these patients. The risk of developing PCOS during VPA treatment seems to be higher in women with epilepsy than in women with bipolar disorders, and this might be due to an underlying neuroendocrine dysfunction related to the seizure disorder. Gynecologists must be aware of the possibility that PCOS in these populations of patients might be related to VPA use, and a careful multi-specialist approach is required for evaluating the risks and benefits of this treatment in the presence of features of PCOS.

Leptin and insulin homeostasis in epilepsy: relation to weight adverse conditions

During managing patients with epilepsy, there is a great risk of weight changes, particularly weight gain with some antiepileptic medications. Weight gain is not only a cosmetic problem that leads to non-compliance to medications but also increases the risk for atherosclerosis and its related complications. The mechanisms underlying weight gain in epilepsy are multiple and controversial and have been attributed to the effect of epilepsy and more commonly the effect of antiepileptic medications on the central and peripheral mechanisms regulating weight homeostasis including the two main homeostatic hormones, leptin, a protein product of obesity gene secreted by adipocytes and insulin, a protein product of pancreatic beta-cells. Increased blood levels of leptin and insulin due to leptin and insulin resistance is observed in patients with epilepsy. Leptin forms an important link between weight gain, insulin resistance, epilepsy and atherosclerosis. The knowledge of the novel roles of leptin in patients with epilepsy will help identification of early markers for the related adverse weight changes, thus allowing proper characterization of suitable antiepileptic medication as initial step during management and follow up of patients.

Characterization of insulin secretion in Valproate-treated patients with epilepsy

PURPOSE

Valproate (VPA) treatment has been reported to be associated with obesity and high fasting serum insulin concentrations in parallel with an unfavorable serum lipid profile and hyperandrogenism and polycystic ovaries in women. The pathogenetic mechanism underlying these changes has remained unknown, although several mechanisms have been implicated.

METHODS

Fifty-one patients receiving monotherapy (31 male and 20 female patients) were included in this study, with 45 (23 male and 22 female) healthy control subjects. These participants were interviewed, clinically examined, and blood samples for fasting plasma glucose, serum insulin, proinsulin, and C-peptide concentrations were taken after an overnight fast.

RESULTS

The valproate-treated patients had fasting hyperinsulinemia (11.30 +/- 6.23 pM vs. 6.28 +/- 4.66 pM in the control subjects; p < 0.001), although the fasting serum proinsulin and C-peptide concentrations were not significantly higher in the patients than in the control subjects. In addition, proinsulin/insulin (0.30 +/- 0.14) and C-peptide/insulin ratios (35.48 +/- 24.09) were lower (p < 0.001) in the VPA-treated patients when compared with the control subjects (0.53 +/- 0.36 and 94.27 +/- 61.85, respectively), and they also had lower fasting plasma glucose concentrations (4.72 +/- 0.35 mM) than the control subjects (5.12 +/- 0.58 mM; p < 0.01).

CONCLUSIONS

This study suggests that valproate does not induce insulin secretion but might interfere with the insulin metabolism in the liver, resulting in higher insulin concentrations in the peripheral circulation. These changes are seen irrespective of concomitant weight gain, suggesting that increased insulin concentrations induce weight gain and not vice versa.

Insulin-related metabolic changes during treatment with valproate in patients with epilepsy

Weight gain is a known side effect of valproate (VPA) therapy, which is associated with hyperinsulinemia and polycystic ovary-like syndrome and unfavorable lipid changes in women. Hyperinsulinemia has also been observed in male and lean subjects as well. Hyperinsulinemia is associated with several health risks, such as cardiovascular diseases and the metabolic syndrome. The purpose of this study was to evaluate whether VPA-related hyperinsulinemia is associated with other metabolic changes and whether there is any association between weight gain, other adverse effects related to VPA, and the metabolic syndrome. Fifty-one patients under VPA monotherapy and 45 healthy control subjects participated in the study. They were interviewed and clinically examined, and, after an overnight fast, blood samples were taken to evaluate fasting serum insulin, lipid, free fatty acid, and uric acid levels. Incidence of the metabolic syndrome was determined as well. Compared with control subjects, VPA-treated patients had higher circulating insulin concentrations relative to body mass index, higher uric acid and triglyceride levels, and lower high-density lipoprotein cholesterol concentrations. There was no significant difference in the frequency of the metabolic syndrome between the VPA-treated patient group and the control group. In conclusion, valproate therapy, especially if started at a young age, is associated with increased circulating insulin concentrations relative to body mass index, indicating that the high insulin levels are not a consequence of obesity. Although the frequency of the metabolic syndrome did not differ between VPA-treated patients and control subjects, VPA-treated patients had higher concentrations of triglycerides and uric acid and lower levels of high-density lipoprotein cholesterol than control subjects.

Serum insulin, leptin, and neuropeptide y levels in epileptic children treated with valproate

Weight gain is a common side effect of valproate treatment. The potential mechanisms of valproate-associated weight gain are not yet clear. Decreased blood glucose level, impairment of beta-oxidation of fatty acids, and increased insulin levels are some of the possible mechanisms. The aim of the present study is to evaluate the role of insulin, leptin, and neuropeptide Y in valproate-related weight gain in epileptic children. In 20 epileptic children treated with valproate before treatment and after a follow-up period of 3 and 6 months, body mass index and fasting insulin glucose ratio were calculated and serum glucose, insulin, cortisol, leptin, and neuropeptide Y levels were measured. At the end of 3 months, the mean body mass index values and the mean serum insulin, fasting insulin glucose ratio, and neuropeptide Y levels increased, whereas the serum glucose levels decreased. After 6 months of treatment, the mean serum cortisol and leptin levels were high, in addition to the body mass index, neuropeptide Y, and fasting insulin glucose ratio. These results suggest that weight gain during valproate treatment might be related to low glucose and high insulin, cortisol, leptin, and neuropeptide Y levels.

Endocrine and metabolic changes in epileptic patients receiving valproic acid

It has been well known for many years that valproic acid (VPA) therapy can induce obesity and important endocrine dysfunctions; among these dysfunctions, the most common are hyperandrogenism, menstrual disorders, polycystic ovary syndrome, hyperinsulinism, and changes in LH, FSH, and sexual and thyroid hormones. Moreover, abnormalities in pubertal development and impaired skeletal growth have been reported. The aim of this review is to analyze the main effects of VPA on endocrinological functions in patients with epilepsy in order to understand in depth the pathophysiological mechanisms and, consequently, to improve the care of these patients.

Fasting serum insulin and lipid levels in men with epilepsy

BACKGROUND

Previous studies suggest that obese women taking valproate (VPA) for epilepsy are insulin resistant.

OBJECTIVE

To assess the effects of antiepileptic drugs on serum insulin and lipid levels in men with epilepsy.

METHODS

Body mass index (BMI) and fasting serum concentrations of insulin and lipids were measured in 102 men with epilepsy who were treated with VPA, carbamazepine (CBZ), or oxcarbazepine (OXC) monotherapy. Thirty-two healthy men served as control subjects.

RESULTS

Obesity was not more common among VPA-treated men than among other men with epilepsy or the control subjects. However, the obese VPA-treated men had higher serum insulin levels (p < 0.001) than the obese control subjects despite similar BMI. CBZ and OXC did not have any significant effect on any of the measurements. Fasting serum insulin concentrations above the normal range were observed in seven obese VPA-treated patients (35%) but in only one obese control subject (5%). Five obese VPA-treated patients (25%) and one obese control subject (5%) had serum triglyceride levels above the normal range, and a low high-density lipoprotein/total cholesterol ratio was observed in two obese VPA-treated patients (10%).

CONCLUSIONS

Obese valproate-treated men have high serum insulin levels, indicating insulin resistance. Moreover, some of the valproate-treated men cluster cardiovascular risk factors such as obesity, hyperinsulinemia, and elevated serum triglyceride concentrations. CBZ and OXC do not seem to have any significant effects on serum insulin or lipid levels in men with epilepsy.

Lamotrigine versus valproate monotherapy-associated weight change in adolescents with epilepsy: results from a post hoc analysis of a randomized, double-blind clinical trial

Recent trends toward obesity and associated health risks in children highlight the significance of weight gain as a side effect with certain antiepilepsy drugs. No previous study has prospectively compared, in adolescents, weight effects for two commonly used antiepilepsy drugs. We report results from a post hoc subanalysis of adolescent data from a randomized, double-blind study comparing weight effects of lamotrigine and valproate. Patients were > or = 12 years of age with new-onset partial or generalized seizures who were randomized 1:1 to lamotrigine or valproate. Patients were escalated to a dose range of 100 to 500 mg/day for lamotrigine and 10 to 60 mg/kg/day for valproate based on clinical response, with target doses maintained for 24 weeks. Results are reported for adolescents aged 12 to 20 years. Weight changes during maintenance were higher (P < .05) in valproate (n = 20) patients than in lamotrigine (n = 18) patients, and change in body mass index was higher (P < .05) in valproate patients at the end of the study. At week 32, mean body mass index in the valproate group was above the 85th percentile representing "at risk for overweight." Whereas weight remained stable in adolescents treated with lamotrigine, weight increased in those treated with valproate by week 10 of this study and continued to increase at the end of the study.

Valproic acid-associated weight gain in older children and teens with epilepsy

This research was undertaken to determine the incidence and predictors of weight gain in older children and teens treated with valproate for epilepsy. Subjects who were 10 to 17 years of age, who began valproate treatment between January 1, 1996, and December 31, 2000, and who had documented weight and height measurements at medication initiation and at least one follow-up visit were retrospectively identified. Exclusion criteria were follow-up <2 months, discontinuation of valproate within 2 months, concurrent therapy with medication known to affect weight, or gastrostomy feeding. Body mass index was calculated at initiation and either discontinuation of valproate or last follow-up and stratified into four categories: underweight, (<fifth percentile), appropriate (fifth to eighty-fifth percentile), potentially overweight (>/=eighty-fifth to ninety-fifth percentile) and overweight (ninety-fifth percentile or higher). Potential predictors of change in body mass index were examined. Mild-to-moderate weight gain was observed in 58% of the 43 subjects treated with valproate (median increase, 2; twenty-fifth to seventy-fifth percentile, 1-6.4). Seventy-nine percent remained in the same body mass index category, and 14% moved up to a potentially overweight or overweight category. The only predictor of an overweight category at follow-up was a potentially overweight or overweight category at initiation (P <0.0002). Two factors tended to predict an increase in body mass index: normal neurocognitive status (P = 0.06) and primary generalized seizure type (P = 0.07).

Serum insulin and leptin levels in valproate-associated obesity

PURPOSE

Weight gain is an important adverse effect of valproate (VPA) therapy, and it is associated with hyperinsulinemia and hyperandrogenism in women with epilepsy. Leptin is considered a signaling factor regulating body weight and energy metabolism. In human subjects, obesity is in general associated with elevated serum leptin levels, suggesting decreased sensitivity to leptin. The present study aimed at evaluating the role of insulin and leptin in VPA-related obesity.

METHODS

Body mass index (BMI) was calculated, and serum insulin and leptin levels were measured in 81 patients with epilepsy taking VPA and in 51 healthy control subjects.

RESULTS

Forty (49%) of the patients taking VPA and 25 (49%) of the control subjects were obese. The mean insulin levels were higher in VPA-treated patients than in the control subjects despite similar BMI values, when all subjects were included in the comparison. Both obese male and female patients taking VPA had higher serum insulin levels than the respective control subjects with similar BMI values. Serum insulin levels also were higher in lean male and lean female patients compared with the lean control subjects of same sex. Serum leptin levels did not differ between the VPA-treated patients and the control subjects.

CONCLUSIONS

Both obese and lean patients taking VPA for epilepsy have hyperinsulinemia, suggesting development of insulin resistance. This may be one of the factors leading to weight gain during VPA treatment. However, the results of the present study do not suggest an independent role for leptin in the pathogenesis of VPA-related obesity.

Adolescent issues in epilepsy

Approximately one third of new cases of epilepsy have their onset before age 20 years. Many children will enter adolescence with epilepsy or have an onset of seizures during adolescence. Adolescence is a time of dramatic change in growth, hormonal, psychologic, and social situations. Seizure frequency, teenage pregnancy, driving, and alcohol and drug use often become major issues during the adolescent years. Furthermore, adolescents often have difficulty accepting the chronicity of epilepsy and complying with medications, which can result in physical injury and perceived or real obstacles to employment, thereby contributing to low morale. Both pediatricians and neurologists should be aware of adolescent issues in epilepsy.

Bodyweight gain and anticonvulsants: a comparative review

Bodyweight gain is a common and frequent undesirable effect associated with the use of anticonvulsant drugs. This has been observed for many years with valproic acid (sodium valproate) and carbamazepine, and also, more recently, with some of the newer anticonvulsants such as vigabatrin and gabapentin. Very often bodyweight gain in children, adolescents and adults with epilepsy taking such anticonvulsants results in cosmetic adverse effects. On the other hand, bodyweight gain is disturbing to general health, with a possible increase in the risk of diabetes mellitus or heart disease. Other potential adverse effects, such as the association of obesity with polycystic ovaries, have been reported with the use of valproic acid. Potential mechanisms of anticonvulsant-associated bodyweight gain are not yet clear and differ between drugs used. The involvement of lowered blood glucose level, which may stimulate eating through an effect on the hypothalamus, constitutes one of the possible mechanisms. Lowered blood glucose levels may result from a competition between the binding of the drug and long chain fatty acids. An increased availability of the latter stimulates insulin production and lowers the serum glucose levels. Another possible explanation for lowered blood glucose may be a deficiency in carnitine directly caused by the drug, that would result in a reduction of fatty acid metabolism and an increase in glucose consumption. An enhancing effect of gamma-aminobutyric acid-mediated neurotransmission may increase appetite for carbohydrates and reduce energy expenditure. An antidiuretic hormone-like effect or effects on norepinephrine (noradrenaline) or serotonin-mediated neurotransmission are more rarely considered. Many studies on anticonvulsant-associated bodyweight gain illustrate how we could better define the risk factors for the development of anticonvulsant-induced bodyweight gain and uncover the mechanisms behind it.

Thyroid function in men taking carbamazepine, oxcarbazepine, or valproate for epilepsy

PURPOSE

Antiepileptic drugs (AEDs) may affect serum thyroid hormone concentrations. This study aimed to evaluate thyroid function in men taking carbamazepine (CBZ), oxcarbazepine (OCBZ), or valproate (VPA) for epilepsy.

METHODS

Ninety men with epilepsy (40 taking CBZ, 29 taking OCBZ, and 21 taking VPA monotherapy) and 25 control subjects participated in the study. After clinical examination, a blood sample for hormone, gamma-glutamyl-transferase (GGT) and antibody (ab) assays was obtained.

RESULTS

Serum thyroxine (T4) and free thyroxine (FT4) concentrations were low in men taking CBZ or OCBZ. Forty-five percent of men taking CBZ and 24% of men taking OCBZ had serum T4 and/or FT4 levels below the reference range. However, no correlations were found between T4 or FT4 and GGT concentrations in men taking CBZ or OCBZ. Thirteen percent of men taking CBZ, 17% of men taking OCBZ, and 6% of control men had increased levels of thyroid peroxidase (TPO)-ab and/or thyroglobulin (TG)-ab, but these were not associated with altered serum thyroid hormone concentrations. Serum triiodothyronine and thyrotropin levels in men taking CBZ or OCBZ were normal. In men taking VPA, the concentrations of thyroid hormones, thyrotropin, and antithyroid ab were normal.

CONCLUSIONS

Serum thyroid hormone concentrations are low in CBZ- or OCBZ-treated men. However, these low levels do not seem to be due to liver enzyme induction or activation of immunologic mechanisms. Therefore, interference with hypothalamic regulation of thyroid function by CBZ and OCBZ seems possible. VPA does not have any significant effects on thyroid function.

Weight gain associated with valproate in childhood

Weight gain is a common side effect of valproate treatment. Several mechanisms have been suggested for its pathophysiology; of these, impairment of beta-oxidation of fatty acids and increased insulin secretion have been supported by clinical studies. To investigate whether changes in carnitine and insulin levels had a role in the weight gain occurring with valproate treatment in children, 20 patients with epilepsy were randomly assigned to receive either carnitine or placebo supplementation in addition to valproate. After a follow-up period of 3 months, weight gain was observed in both groups. The mean insulin concentration and insulin/glucose ratios increased. Weight gain did not correlate with carnitine levels. These results suggest that weight gain during valproate treatment is not related to a decrease in carnitine levels. However, an increase in insulin levels together with a decrease in glucose levels may cause weight gain, possibly by stimulating appetite.

Risk of excessive weight gain in epileptic children treated with valproate

We sought to identify factors associated with excessive weight gain in children treated with valproate, excluding patients fed by gastrostomy or treated with medications known to affect appetite (eg, stimulants). Weight and height were recorded before treatment and at the time of follow-up; a measure of adiposity, body mass index, was computed and expressed in kg/m2, and weight and height for age were converted to Z-score. Putative risk factors included sex, age at start of treatment, monotherapy at start of treatment, duration of follow-up, mental retardation, seizure type (generalized or partial), etiology (idiopathic or cryptogenic versus remote symptomatic), and dose of valproate. Fifty-five children (30 girls, 25 boys), ranging in age at the start of therapy from 1.8 to 16.9 years were followed for 8.6 to 33.8 months. Forty-three patients had primarily generalized seizures, 34 had idiopathic or cryptogenic epilepsy (including 30 with generalized idiopathic epilepsy), and 18 had mental retardation. Valproate was the first antiepileptic drug for 21 patients, and 43 were on monotherapy at the time of follow-up. Height Z-score decreased significantly in girls but was stable in boys. There was a significant increase in body mass index and in weight Z-score. Body mass index was greater than the 90th percentile for age in 14 patients at the start of treatment and in 20 patients at follow-up. Decrease in height Z-score was significantly correlated with female sex and duration of follow-up. Changes in weight Z-score and body mass index were significantly correlated with initial weight Z-score and initial body mass index, respectively, but not with age at start of therapy, duration of follow-up, sex, seizure type, etiology, dose of valproate, or monotherapy.

Influence of sex differences on the renal secretion of organic anions

The kidney's responsiveness to male sexual hormones has been often neglected. Renal secretion of organic anions is higher in male than in female individuals; as a consequence, most of the xenobiotics that are excreted from the organism through this pathway are eliminated more rapidly by males than by female animals. To gain further insight into this issue, we studied in vitro and in vivo characteristics of the transport of p-aminohippurate (PAH), a suitable marker for this system, in male and female rats, under different hormonal conditions. Kinetics of PAH showed a shorter elimination half-time in male than in female rats (t(1/2el): male = 16.2 +/- 2.1 min, female = 25.7 +/- 4.5 min, P < 0.05). Castration of male rats increased t(1/2el) to a value similar to that of female rats (t(1/2el): orchiectomized rat = 28.1 +/- 7.1 min). Testosterone treatment of female rats increased the elimination rate to a value similar to that of male rats. In vitro PAH uptake by renal cortical slices from intact male rats was higher than that by slices from orchiectomized rats. Kinetic analyses of PAH uptake suggest that the difference was caused by a lower number of transporting molecules in orchiectomized than in intact animals, whereas the transporting capacity for each carrier was similar in male and in orchiectomized rats. Our results suggest that testosterone increases the number of functional carriers for PAH in the kidney.

Weight gain in epileptic patients during treatment with valproic acid: a retrospective study

BACKGROUND

Weight gain has been recognized as a common adverse effect of valproic acid (VPA) that leads to discontinuation in some patients but its incidence and correlates have been rarely studied.

METHODS

We have analyzed the records retrospectively and interviewed 70 adult patients attending an epilepsy clinic on VPA mono- or polytherapy followed over a median of 27 months (range 3-189), as well as 20 patients on carbamazepine (CBZ) monotherapy. Patients were divided into non-weight gainers (< 5% baseline body weight), mild-moderate weight gainers (5-10% body weight) and marked weight gainers (> 10% body weight). The following variables were statistically analyzed to determine their relationship to weight gain: gender, age, body mass index, drug dose, personal or family history of obesity and monotherapy versus polytherapy.

RESULTS

Seventy-one percent of the VPA group were weight gainers versus 43% in the CBZ group. A weight gain of more than 4 kg in 70% of the VPA group was observed. The weight gain was often sustained and frequently socially significant to the patients. Patients below or within normal range body mass index prior to the start of VPA experienced the most severe percentage weight gain. From the structured patient interviews, patients with no personal history of weight problems experienced the greatest initial weight increase.

CONCLUSION

Strategies should be devised to help patients avoid weight gain when starting on VPA, especially if they are not already overweight.

Weight gain with valproate or carbamazepine--a reappraisal

The use of valproate has traditionally been held to be associated with a greater incidence of weight gain than that of other anticonvulsants. This paper presents an analysis of body weight data gathered during a randomized trial comparing valproate with carbamazepine in 260 children aged 4-15 years with newly-diagnosed epilepsy. There were more reports of weight gain as an adverse event in the valproate group than in the carbamazepine group (22 reports in 14 patients vs. nine reports in five patients). However, amongst the 211 patients (103 on valproate and 108 on carbamazepine) in whom objective weight measurements were taken during treatment, there were no differences between the treatments in percentage weight gain from baseline or incidence of excessive weight velocity. Eight patients reporting weight gain on valproate were switched to carbamazepine because of poor seizure control and/or adverse events including weight gain, but three of the four patients for whom body weight measurements were available continued to gain weight on carbamazepine. It is concluded that weight gain may be erroneously attributed to valproate treatment.