Thyroid Function with Antiepileptic Drugs

Serum thyroid hormone balance was assessed in 108 patients receiving chronic antiepileptic drug (AED) therapy. Forty-five patients were receiving carbamazepine (CBZ), 26 phenytoin (PHT), 16 CBZ-PHT, 11 valproate (VPA), and 10 CBZ-VPA. Serum thyroxine (T4) and free thyroxine (FT4) concentrations were low in patient groups receiving CBZ and/or PHT. Serum T4 concentrations were below the normal range in 24 (53.3%) CBZ patients, 11 (42.3%) PHT patients, 12 (75%) CBZ-PHT patients, and in all 10 patients (100%) receiving CBZ-VPA. Furthermore, serum levels of FT4 were below the normal range in 13 (28.9%) CBZ patients, 6 PHT (23.1%) patients, 5 (31.3%) CBZ-PHT patients, and 5 (50%) CBZ-VPA patients. Despite the decreased serum T4 and FT4 levels in these patients, serum basal and stimulated thyrotropin (TSH) concentrations were normal, except for the slightly increased basal TSH in the CBZ-VPA group. In the VPA group, the findings were different from those in other patients: T4 serum levels were unchanged and FT4, T3, and basal TSH levels increased, but stimulated TSH levels did not differ from those of the control group. The decrease in serum thyroid hormone levels during CBZ and/or PHT medication probably is caused by an accelerated hepatic plasma clearance of these hormones due to induction of hepatic microsomal enzyme systems by these AEDs. VPA, an AED with no liver enzyme-inducing properties, does not cause similar changes. The feedback mechanism is not activated, possibly because of a hypothalamic interference by CBZ and PHT.(ABSTRACT TRUNCATED AT 250 WORDS)     

Carbamazepine and risk of hypothyroidism: a prospective study

OBJECTIVES - While carbamazepine (CBZ) decreases thyroid hormone concentrations it rarely causes hypothyroidism. We assessed prospectively the early effect of CBZ on thyroid status in thyroxine-supplemented hypothyroid patients, when compared with patients without a thyroid disorder. METHODS - In 29 patients, thyrotropin (TSH), total thyroxine (TT4) and free thyroxine (FT4) serum levels were assayed before starting CBZ, and then weekly for 7 weeks. Nineteen patients with no thyroid disorder (group A) were compared with 10 thyroxine-supplemented hypothyroid patients, stable before CBZ treatment (group B). RESULTS - In group A, TT4 decreased significantly by ca. 15-25%, starting from the first week (Friedman, P < 0.001). FT4 decline was smaller (ca. 10-15%) and delayed till the second week. FT4/TT4 ratio increased significantly (P < 0.001), while TSH only slightly (P = 0.073), never exceeding normal range. In group B, similar TT4 and FT4 decline was followed by significantly increasing TSH (P = 0.011), while the FT4/TT4 ratio was not significantly changed. In 3 of 10 patients TSH rose over 5 mIU/l, necessitating treatment adjustment. CONCLUSIONS - In patients with no thyroid disorder, CBZ causes hormonal changes of no clinical relevance, due to adaptive response. In T4-supplemented hypothyroid patients this adaptation is lacking, CBZ may precipitate subclinical or overt hypothyroidism, and early thyroid function monitoring seems advisable.     

Influence of carbamazepine on serum thyroxine and triiodothyronine in patients with epilepsy

Hypothyroidism induced by anti-epileptic drug treatment gave rise to thyroid function test studies in patients treated with carbamazepine (CBZ) only. In 42 patients on long-term CBZ treatment thyroxine (T4), free T4-index (FT4I), and triiodothyronine (T3) concentrations in serum were significantly lower than in controls, while triiodothyronine uptake (T3U) and thyrotropin (TSH) concentrations did not differ between patients and controls. In 12 patients starting on CBZ, means T4, calculated FT4 and thyroxine binding globulin (TBG) were 1-5 months later reduced compared to the initial levels. Thus, CBZ reduced thyroid hormones, TBG and FT4I. A CBZ-induced increase in conversion and metabolism of the thyroid hormones could explain this effect. The normal T3U values and decreased concentrations of TBG make a competitive CBZ binding to TBG less probable. Although the thyroid hormones levels were found lowered in the patients, all remained clinically euthyroid during the study.     

Evaluation of thyroid and parathyroid functions in children receiving long-term carbamazepine therapy

We studied serum calcium, phosphorus, alkaline phosphatase (ALP), thyroid hormones (total thyroxine [TT4], free thyroxine [FT4], thyroid-stimulating hormone [TSH]), parathyroid hormone (PH), and osteocalcine levels in children with epilepsy who had been receiving long-term carbamazepine (CBZ) therapy to determine whether there was any effect of CBZ therapy on these hormones. The study included 18 patients with epilepsy receiving CBZ and 16 healthy age-matched controls. The age ranged from 4-18 years (11.26 +/- 3.59 years) and 4.5-17 years (11.16 +/- 3.13 years) in the study and control group, respectively. The duration of CBZ use was between 10 months-5 years (3.12 +/- 1.09 years). When comparing the results we did not find any significant difference in serum calcium, phosphorus, ALP, osteocalcine and TSH and PH levels between the groups (p >.05). However, serum TT4 and FT4 levels were found to be significantly lower in the study group than those of control group (p <.05). However, we observed no clinical signs of hypothyroidism in all subjects. To these findings we suggest that serum thyroid hormone levels should be monitored in children receiving long-term CBZ therapy.     

Brief Communication: EVALUATION OF THYROID AND PARATHYROID FUNCTIONS IN CHILDREN RECEIVING LONG-TERM CARBAMAZEPINE THERAPY

We studied serum calcium, phosphorus, alkaline phosphatase (ALP), thyroid hormones (total thyroxine [TT4], free thyroxine [FT4], thyroid-stimulating hormone [TSH]), parathyroid hormone (PH), and osteocalcine levels in children with epilepsy who had been receiving long-term carbamazepine (CBZ) therapy to determine whether there was any effect of CBZ therapy on these hormones. The study included 18 patients with epilepsy receiving CBZ and 16 healthy age-matched controls. The age ranged from 4-18 years (11.26 &#45 3.59 years) and 4.5-17 years (11.16 &#45 3.13 years) in the study and control group, respectively. The duration of CBZ use was between 10 months-5 years (3.12 &#45 1.09 years). When comparing the results we did not find any significant difference in serum calcium, phosphorus, ALP, osteocalcine and TSH and PH levels between the groups (p >. 05). However, serum TT4 and FT4 levels were found to be significantly lower in the study group than those of control group (p <. 05). However, we observed no clinical signs of hypothyroidism in all subjects. To these findings we suggest that serum thyroid hormone levels should be monitored in children receiving long-term CBZ therapy.­­     

抗癫痫药物对癫痫患者甲状腺激素水平影响的研究

目的 研究癫痫患者甲状腺激素水平和抗癫痫药物对其影响以及与疗效之间的关系。方法 测定已确诊的45例未服用过抗癫痫药物的癫痫患者血清甲状腺激素水平并与30例健康对照组进行比较。再经卡马西平、苯妥英钠、丙戊酸钠三种抗癫痫药物分组单药治疗3个月、6个月、年后观察甲状腺激素水平的变化及与疗效之间的关系。结果 未服用抗癫痫药物的新诊断癫痫患者游离甲状腺素（FT4）水平显著低于健康对照组,经苯妥英钠、卡马西平分别治疗3个月、6个月、1年后T4、FT4、FT3显著低于治疗前水平,TSH无显著性变化。经丙戊酸钠治疗后的不同时间段各甲状腺激素水平与治疗前比较无显著性差异（P＞0．05）。甲状腺激素水平的变化与化疗效之间似无相关性。结论 癫痫的反复发作虽未经抗癫痫药物治疗已存在FT4水平的降低。苯妥英钠、卡马西平可明显造成癫痫患者的亚临床甲状腺功能降低（T4、FT4、FT3下降）,丙戊酸钠对患者甲状腺激素水平无显著影响。甲状腺激素水平的变化与疗效之间无相关性。     

Serum concentrations of circulating thyroid hormones in a group of depressed men

Levels of circulating total thyroxine (TT4), free thyroxine (FT4), total triiodothyronine TT3 and thyrotropin (TSH) were determined in 27 men with unipolar major depressive disorder ages 24-50, mean +/- SEM 36.9 +/- 2.9 years, and 38 healthy controls (HC) ages 20-50, mean +/- SEM 34.2 +/- 3.1 years. No significant differences were observed between HC and depressed men with regard to TT4 and FT4. Mean TT3 levels were lower, and mean TSH levels higher in depressed patients than in HC, p less than 0.05 for both, compatible with possible subclinical primary hypothyroidism in depressed patients. Consistent with this, an inverse correlation between basal TSH values and TT3 (r = -0.38, p less than 0.05) was noted in depressed but not in HC subjects.     

The effects on lipid and apolipoprotein serum levels of long-term carbamazepine, valproic acid and phenobarbital therapy in children with epilepsy

The aim of the present study was to assess the effect of long-term carbamazepine (CBZ), valproic acid (VPA) and phenobarbital (PB) treatment on serum lipids and apolipoproteins in epileptic children. Serum levels of total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), very low-density lipoprotein cholesterol (VLDL-C) and triglycerides (TGs) were measured and the LDL-C/HDL-C and TC/HDL-C ratios were calculated in 320 children and adolescents (129 receiving CBZ, 127 receiving VPA and 64 receiving PB) suffering from various types of epilepsy. Additionally, in a subgroup of 181 children (68 CBZ; 78 VPA; 35 PB) apolipoprotein A-I (apoA-I), apolipoprotein B (apoB), HDL2-C and HDL3-C were measured and apoA-I/apoB and HDL2-C/HDL3-C ratios were calculated. Results of the measurements were compared with those of 169 age-and sex-matched healthy controls. None of the variables considered was significantly correlated with time elapsed since start of treatment or with drug concentration in serum. TC and LDL-C serum levels were high in children receiving CBZ or PB and low in those treated with VPA. Serum LDL-C level exceeded 130 mg/dl in 27.9% of CBZ-group, 31.8% of the subjects receiving PB, but only in 7% of those receiving VPA and in 11.8% of control group subjects. CBZ-treated children also showed high HDL-C and HDL3-C values. In the group receiving VPA, HDL2-C, HDL2-C/HDL3-C ratio and apo B were significantly lower than in the control group. Mean apoA-I levels were low in all treated groups: by contrast, in neither group did TGs, VLDL-C levels and TC/HDL-C or LDL-C/HDL-C ratios differ significantly from the corresponding control group. Our results suggest that the effects of long-term AED therapy on lipid profile and, particularly, on apolipoprotein serum levels increase risk of atherosclerosis-related disease. Moreover, these results confirm our previously reported increased risk in CBZ and PB-treated patients.     

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.     

Subclinical hypothyroidism during valproic acid therapy in children and adolescents with epilepsy

The aim of this study was to evaluate the incidence of thyroid dysfunction during valproic acid (VPA) therapy in children and adolescents with epilepsy. The serum levels of thyroid-stimulating hormone (TSH), free thyroxine, and triiodothyronine were evaluated in 61 children with epilepsy who received VPA monotherapy for more than 6 months and in 144 controls. We analyzed the effect of age, seizure type, duration of VPA treatment, dose of VPA, and serum level of VPA on thyroid function. The incidence of subclinical hypothyroidism was significantly higher in patients with VPA therapy than in controls (52.4 vs. 16.7%; p < 0.001). In addition, of the 61 patients, 5 (8.1%) exhibited TSH levels that were >10 μIU/mL. However, none of the patients and controls showed overt hypothyroidism. Serum VPA level and daily dose of VPA were correlated with TSH level. Subclinical hypothyroidism developed frequently in children and adolescents during VPA therapy.     

Grades 1 and 2 hypothyroidism in a state mental hospital: Risk factors and clinical findings

Thirty-six chronically psychotic patients (nine men and 27 women, mean age 56.7 +/- S.D. 13.4 years) were found to have elevated thyroid stimulating hormone (TSH) levels during review of thyroid function screening tests of 1150 patients over a 15 month period in a 700 bed state mental hospital. This study population of 36 patients was more likely to be female and older than the general hospital population. The spectrum and frequency of psychiatric diagnoses included dementia (3); schizoaffective disorder (12); bipolar disorder (6); schizophrenic disorder (4); organic affective disorder (7); major depression (3); and mental retardation (1). Only nine of these 36 patients failed to receive the goitrogens lithium (LI), carbamazepine (CBZ) and/or phenytoin (PTN) and five of those nine patients had a history of thyroid disease. Sex did not predict age, thyroxine (T4) level, triiodothyronine (T3) uptake, or TSH. The distribution of psychiatric diagnoses were the same for both sexes. Expectedly, there was an inverse relationship between TSH and T4 and T3 uptake. Using T4 to separate grades 1 and 2 hypothyroidism revealed that six (17%) patients had grade 1 disease. Men were more likely to have a seizure disorder and receive LI, CBZ, and PTN. Women were more likely to have a history of thyroid disease. The goitrogenic effects of LI + CBZ seemed additive compared with patients receiving LI alone. While T4, T3 uptake, and LI levels were the same for the two groups, patients receiving LI + CBZ had higher TSH values (p = 0.028) than did patients receiving LI alone.(ABSTRACT TRUNCATED AT 250 WORDS)     

Thyroid and Myocardial Function After Replacement of Carbamazepine by Oxcarbazepine

Summary: We determined changes in serum concentrations of thyroid hormones during carbamazepine (CBZ) therapy during a 5-year prospective follow-up study of 20 patients with newly diagnosed epilepsy. In addition, we evaluated the effects of replacing CBZ with oxcarbazepine (OCBZ) in 12 male patients with epilepsy in a 6-month prospective follow-up study. Circulating thyroxine and free thyroxine levels decreased after 2-month CBZ treatment and remained at a low level during the 5-year follow-up. There were no associated changes in serum thyrotropin (TSH) concentrations. When CBZ was replaced by OCBZ, the function of the liver's P450 enzyme system normalized, as shown by an increase in antipyrine_T1/2, and a decrease in antipyrine_CL. Serum total and free thyroxine levels increased, and thereafter serum TSH levels decreased. Indexes of diastolic heart function improved concomitantly, which may reflect subclinical hypothyroidism at the cellular level during CBZ treatment. We conclude that normal thyroid function can be restored in patients with epilepsy by replacing CBZ with OCBZ.     

Thyroid function in Down syndrome.

The thyroid function of 181 patients with Down syndrome was investigated. When compared with a control group of 163 children we found T4 and FT4 levels to be significantly lower and T3 and TSH levels to be significantly higher in the Down syndrome population. Of the 181 patients with Down syndrome, 29 (16%) showed evidence of either uncompensated or compensated hypothyroidism: 11 (6%) had both low T4 and high TSH levels, 14 (8%) had only high TSH values, and 4 (2%) had only low T4 values. One of the patients with Down syndrome had a significantly elevated T4 level. Studying different age groups, we observed a decline of the mean T4, FT4, T3, FT3, and TBG values with advancing age. T4, T3, and TSH blood levels obtained in 1988 were slightly but not significantly lower when compared with values from 1985. Because thyroid dysfunctions in patients with Down syndrome are more common than in the general population, periodic thyroid hormone function tests should be performed in persons with Down syndrome in particular as they advance in age. Thus, individuals with significantly abnormal results can be identified early before clinical symptoms become manifest. If patients with Down syndrome are found to have a thyroid hormone disorder, appropriate treatment should be forthcoming, which in turn will enhance their quality of life.     

Pharmacokinetic Interactions Between Lamotrigine and Other Antiepileptic Drugs in Children with Intractable Epilepsy

Summary: Purpose : We wished to determine the oral pharmacokinetics of lamotrigine LTG and to assess possible interactions with other AEDs in an unselected population of children. Concentration data in plasma and in CSF for lamotrigine as well as for the other AEDs are presented.
Methods : Thirty-one children, children and young adults aged > 2 years with intractable generalized epilepsy despite adequate duration and dose of at least three conventional AEDs were studied.
Results : There was a linear relation between the dose administered and the maximal plasma concentration, indicating that saturation of absorption or elimination mechanisms did not occur in the dose range studied. The median elimination half-life (t1/2) in patients receiving concomitant valproate (VPA) was 43.3 h; in patients receiving carbamazepine (CBZ) and/or phenobarbital (PB), it was 14.1 h; and in patients receiving both VPA and CBZI PB or other antiepileptic drugs (AEDs), it was 28.9 h. No clinically important changes in the plasma levels of CBZ, VPA, valproate, ethosuximide, or PB were observed in the follow-up period (2–12 months). No dose adjustments of concomitant AEDs were necessary. The plasma concentration of clonazepam (CZP) was reduced when LTG was introduced.
Conclusions : The complex interaction between LTG and other AEDs in children with intractable epilepsy makes therapeutic drug monitoring (TDM) desirable.     

Thyroid function in girls with epilepsy with carbamazepine, oxcarbazepine, or valproate monotherapy and after withdrawal of medication

Summary: Purpose: Antiepileptic drugs may affect the serum thyroid hormone concentrations. The aim of this study was to evaluate thyroid function in 78 girls taking carbamazepine (CBZ), oxcarbazepine (OXC), or valproate (VPA) monotherapy for epilepsy and after withdrawal of the treatment. Methods: Forty‐one girls taking VPA, 19 taking CBZ, and 18 taking OXC for epilepsy, as well as 54 healthy age‐matched controls, aged 8 to 18 years, participated in the study. All the girls were examined clinically, and their pubertal stage was assessed. Blood samples were obtained for thyroid hormone and antibody assays. These examinations were repeated after a mean follow‐up of 5.8 years to assess thyroid function, and 64 (82%) of 78 patients and 42 (78%) of 54 controls agreed to participate in the second evaluation. Results: In the first evaluation, the mean serum thyroid hormone concentrations were lower in the girls taking CBZ [thyroxine (T₄), 70.2; SD, 10.9 nM; and free thyroxine (FT₄), 11.5; SD, 1.8 pM] or OXC (T₄, 74.9; SD, 16.4 nM; and FT₄, 11.3; SD, 1.8 pM) than in the control girls (T₄, 96.6; SD, 15.1 nM, and FT₄, 14.4; SD, 1.5 pM; p < 0.001, all comparisons). However, thyrotropin (TSH) concentrations were normal in the girls taking CBZ or OXC. Sixty‐three% of the girls taking CBZ and 67% of the girls taking OXC had serum T₄ and/or FT₄ levels below the lower limit of the reference range. The VPA‐treated girls with epilepsy had normal serum T₄ and FT₄ concentrations, but slightly increased TSH levels (3.3; SD, 1.5 mU/L; p < 0.01) compared with the control girls (2.5; SD, 1.0 mU/L). Normal serum hormone concentrations were restored in the patients who discontinued the medication. Conclusions: Both CBZ and OXC reduce serum thyroid hormone concentrations in girls with epilepsy. Conversely, VPA is associated with normal serum thyroid hormone and increased thyrotropin levels. However, our results suggest that the changes in serum thyroid hormone and thyrotropin levels are reversible after withdrawal of the medication.     

Effects of antiepileptic drugs on delivery and early childhood--comparison among mono-therapies of valproic acid, phenytoin, carbamazepine and phenobarbital

The effects of antiepileptic drugs (AED) on infants during pregnancy and delivery were studied in a total of 82 epileptic mothers on various monotherapies; 29 cases receiving valproic acid (VPA), 20 receiving phenytoin (PHT), 18 on carbamazepine (CBZ) and 15 on phenobarbital (PB). While AED serum concentrations were low in most cases of VPA, PHT and PB except for one case of VPA which exceeded therapeutic limits, concentrations were within therapeutic levels in many cases of CBZ. Conclusion: When compared with normal controls, abnormal deliveries such as caesarian section were seen more frequently in epileptic mothers under AED treatment. In addition, infants in PB cases were shown to have significantly lower mean birth length, weight and head circumference, suggesting that PB may retard fetal growth. The incidence of malformation in cases of VPA, PHT, CBZ and PB, was 10.3%, 5.0%, 0% and 6.7%, respectively. There were five types of malformation: in VPA cases, spina bifida, Siamese twins and ventricular septal defect tended to be severe, while in PHT and PB cases, cor biloculare and hypospadias respectively were observed. In cases of VPA, serum levels in the umbilical cord were found to be 150% higher than those in the mother.     

Thyroid Status of Patients Receiving Long-Term Anticonvulsant Therapy Assessed by Peripheral Parameters: A Placebo-Controlled Thyroxine Therapy Trial

Summary: Thyroid hormone concentrations and measures reflecting thyroid function were studied in sera from 35 patients receiving long-term phenytoin (PHT) or carbamazepine (CBZ) therapy. The mean concentrations of T⁴ FT⁴ FT³ and rT³ but not T³ of these patients were significantly lower than those of 19 controls of similar age and sex distribution. The mean serum thyrotropin (TSH) concentration was slightly but significantly higher in patients than in controls, but the serum TSH response to TRH was not significantly increased. In patients, the higher mean clinical diagnostic index of hypothyroidism (CDI-HT: -20.3 ±-19.1 vs.-33.7 ± 8.5, p < 0.05) and higher ratio of preejection period to left ventricular ejection time (PEP/LVET: 0.343 5 0.065 vs. 0.334 2 0.030, p < 0.05) than in controls were compatible with tissue hypothyroidism. However, comparison of the mean levels of alanine aminotransferase (ALAT), creatine kinase (CK), creatinine, triglycerides, cholesterol, high-density lipoprotein (HDL) cholesterol, osteocalcin, procollagen type III aminoterminal propeptide, and somatomedin-C showed no significant differences between patients and controls. The increased mean angiotensin convertase and sex hormone-binding globulin (SHBG) levels, typical of hyperthyroidism, were probably caused by drug effects. Fourteen patients with a subnormal FT⁴ concentration in serum participated in a doubleblind thyroxine treatment cross-over study. Neither the mean CDI-HT score, nor the systolic time intervals were significantly different between the thyroxine and placebo periods. Five patients benefited subjectively from the treatment. On the basis of all data from the cross-sectional and thyroxine treatment studies, we conclude that patients receiving anticonvulsant drugs chronically are eumetabolic and do not need thyroxine supplementation.     

Thyroid hormones in children on antiepileptic therapy

The aim of this study was to evaluate the thyroid function alterations in a group of epileptic children taking antiepileptic drugs (AEDs). Patients demographic data and the free throxine (fT4) and thyroid-stimulating hormone (TSH) levels at the beginning of the treatment and at the third, sixth and ninth months of AED treatment were recorded retrospectively. A total of 106 children, 59 males and 47 females, were enrolled in the study. Mean patient age was 3.7 years, ranging between 3 months and 14 years. In total, 54% of patients were on valproic acid (VPA), 16% phenobarbital (PB), 14% were on carbamazepine (CBZ), 6% were on oxcarbazepine (OXC), 5% were on levetiracetam, and 5% were on topiramate therapy. There were no significant differences in average fT4 values between the drug groups. But the mean fT4 levels of the patients on VPA therapy showed a clear decrease within the observation period. No significant difference in average TSH values between the groups was detected in the beginning and in the third and sixth month. However, in the ninth month, a significant increase in TSH values was found in the VPA group (p = 0.007). In the patients taking VPA, average TSH values rose progressively while staying within normal limits. During follow-up, thyroid dysfunction were found in 21 patients (19.6%). A statistically significant relationship was found between severe electroencephalography (EEG) findings and thyroid dysfunction (p = 0.041). It was concluded that epileptic children with severe EEG findings and using VPA could have thyroid dysfunction. These patients should be followed up closely by thyroid function tests during treatment.     

Comparison the cognitive effect of anti-epileptic drugs in seizure-free children with epilepsy before and after drug withdrawal

We studied the cognitive effects of antiepileptic drugs (AED), by investigating epileptic children who were seizure-free for at least 2 years and who had undergone fixed monotherapy. Seventy consecutive epileptic children (25 with carbamazepine (CBZ), 22 with phenobarbital (PB), and 23 with valproate (VPA)) were examined by Wechsler Intelligence Scale for Children-Revised (WISC-R) and auditory event-related potentials (P(300)) at three sessions: before AED reduction, then 1 and 7 months after complete withdrawal of treatment. There were no significant differences in IQ and subtests scores of WISC-R in any group at any of the three sessions. P(300) latencies were significantly increased in the children receiving PB but not in children receiving CBZ or VPA. P(300) amplitudes were increased but not significantly different among the three groups. These findings suggest that PB may affect cognitive function on children, but the changes of P(300) latencies may improve after discontinuation.