Does carbamazepine cause disturbances in calcium metabolism in epileptic patients?

Unraveling the nutritional challenges in epilepsy: Risks, deficiencies, and management strategies: A systematic review

BACKGROUND

Malnutrition and epilepsy share a complex bidirectional relationship, with malnutrition serving as a potential risk factor for epilepsy development, while epilepsy, in turn, often exerts profound effects on nutritional status. Nutritional interventions have emerged as a critical adjunctive approach in epilepsy management.

AIM

To explore the multifaceted associations between malnutrition and epilepsy, structured into three primary sections: (1) Elucidating the impact of malnutrition as a risk factor for epilepsy onset; (2) Examining the reciprocal influence of epilepsy on nutritional status, and (3) Evaluating diverse nutritional interventions in the management of epilepsy.

METHODS

A systematic search was conducted across PubMed, Scopus, and Web of Science databases utilizing defined keywords related to malnutrition, epilepsy, and nutritional interventions. Inclusion criteria encompassed various study types, including clinical trials, animal models, cohort studies, case reports, meta-analyses, systematic reviews, guidelines, editorials, and review articles. Four hundred sixteen pertinent references were identified, with 198 review articles, 153 research studies, 21 case reports, 24 meta-analyses, 14 systematic reviews, 4 guidelines, and 2 editorials meeting the predefined criteria.

RESULTS

The review revealed the intricate interplay between malnutrition and epilepsy, highlighting malnutrition as a potential risk factor in epilepsy development and elucidating how epilepsy often leads to nutritional deficiencies. Findings underscored the importance of nutritional interventions in managing epilepsy, showing their impact on seizure frequency, neuronal function, and overall brain health.

CONCLUSION

This systematic review emphasizes the bidirectional relationship between malnutrition and epilepsy while emphasizing the critical role of nutritional management in epilepsy treatment. The multifaceted insights underscore the need for a holistic approach to addressing nutritional aspects alongside conventional epilepsy management strategies.

Antiepileptic drugs carbamazepine and valproic acid mediate transcriptional activation of CYP1A1 via aryl hydrocarbon receptor and regulation of estrogen metabolism

Cytochrome P450 1A1 (CYP1A1) actively catalyzes estrogen hydroxylation reactions and maintains the levels of neuroactive steroid estradiol. The widely prescribed first-line anti-epileptic drugs (AEDs) are considered to be a potent inducer of CYP1A1 and have also been observed to affect serum estradiol and calcium levels in patients with epilepsy. However, the ability of AEDs to interfere with CYP enzyme function and estrogen disposition is a relatively unexplored area. Here we investigate the effect of widely prescribed AEDs (carbamazepine and valproic acid) on CYP1A1 regulation and the levels of estradiol and calcium in cell supernatants of hepatocellular, HepG2, and neuronal, SH-SY5Y cells. We observed that both the AEDs significantly increased CYP1A1 expression and enzyme activity, which was accompanied by a decrease in estradiol and calcium levels in HepG2 cells. This induction of CYP1A1 mRNA and protein was fully prevented by aryl hydrocarbon receptor (AHR) knockdown and StemRegenin 1 (SR1) antagonism. Notably, the AEDs did not affect the AHR expression but regulated its nuclear translocation, potentially driving the transcriptional upregulation of CYP1A1. Furthermore, the knockdown of CYP1A1 in HepG2 cells elucidated a marked increase in estradiol and calcium levels. Later, this increase subsided upon AED exposure. Lastly, we observed a similar trend in estradiol and calcium alterations in SH-SY5Y cells on AED exposure, speculating the involvement of CYP1A1 induction via AEDs at neuronal sites. This work demonstrates that AEDs mediate the upregulation of CYP1A1 via an AHR-dependent mechanism and influence estrogen and calcium homeostasis.

A Prospective Longitudinal Study of the Effects of Eslicarbazepine Acetate Treatment on Bone Density and Metabolism in Patients with Focal-Onset Epilepsy

BACKGROUND AND OBJECTIVES

Eslicarbazepine acetate (ESL) is a third-generation anti-seizure medication for patients with focal-onset epilepsy. There are known short-term impacts of classic enzyme-inducing drugs on bone health. For oxcarbazepine, which like ESL is a less potent inducer of cytochrome P450 (CYP450) than carbamazepine, some studies have shown that treatment is associated with increased bone metabolic parameters. The effects of ESL on bone health have not been systematically evaluated so the objective of this study was to investigate whether adverse effects of ESL on bone mineral density (BMD) could be measured after a 12-month exposure period. In addition, the effects of ESL on bone turnover were investigated using laboratory indicators of bone metabolism.

METHODS

BONAPARTE was a prospective, longitudinal, observational study that enrolled patients with focal-onset epilepsy with or without secondary generalization who started treatment with ESL, either as adjunctive treatment or monotherapy, at two tertiary epilepsy centres in Germany between February 2018 and July 2020. Standardised osteodensitometry and biochemical bone metabolism parameters at the time of ESL initiation and 1 year after continuation of therapy were assessed. Comparisons between biochemical and densitometric parameters at baseline and after 12 months of treatment were performed using the paired samples t test.

RESULTS

In total, 26 patients (15 male; mean age 41.4 ± 12.5 years) newly treated with ESL were evaluated. Six of these patients had osteopenia at baseline. The mean daily dose of ESL at the 12-month follow-up was 1438 ± 1406 mg. At the group level, there were no significant effects of treatment with ESL on laboratory markers or on BMD. Mean values of BMD in g/cm2 at baseline and after 12 months of ESL treatment were 1.17 (± 0.16) and 1.16 (± 0.16) in the lumbar spine, and 0.98 (± 0.15) and 0.96 (± 0.15) in the proximal femur, respectively. Intra-individually, two patients developed de novo osteopenia measured at the femoral neck associated with relevant changes in bone metabolic parameters.

CONCLUSION

Neither osteodensitometry nor bone metabolism parameters showed significant group effects after 1 year of treatment with ESL. Individual fluctuations were observed, however, which may warrant monitoring for longer follow-up periods. The study was registered in the German register for clinical studies under the number DRKS00010430 with the official name BONAPARTE.

Impaired bone health as a co-morbidity of epilepsy

Increasing number of studies shows significant reductions in bone mineral density in patients with epilepsy treated with enzyme-inducing anti-seizure medications (EIASM), valproic acid, and newer anti-seizure medications (ASM). ASM seems to be a specific risk factor for the development of osteoporosis affecting 11%-31% of patients with epilepsy and leads to 2 to 6 times increased risk of fractures compared to the background population. Treatment with ASM clearly contributes to epilepsy-associated bone disease. Yet, the exact pathophysiological mechanism has not been established; however, several hypotheses were suggested, especially in relation to EIASM. As the long-lasting medical treatment, often in polytherapy, has shown negative effects on bone health, it indicates the need for guidelines for the prevention and management of bone disease to be included in the follow-up of patients with epilepsy. An algorithm for following bone status during the treatment has been suggested based on Danish national guidelines.

Determination of serum carbamazepine and its metabolite by validated tandem mass spectrometric method and the effect of carbamazepine on various hematological and biochemical parameters

OBJECTIVES

The study aimed to develop a validated LC-MS / MS method for the measurement of carbamazepine and carbamazepine-10,11-epoxide (CBZE) levels, to compare the carbamazepine concentrations measured by AbSciex API 3200 LC-MS/MS and Beckman Coulter Emit® 2000 immunoassay and to investigate the effect of carbamazepine concentrations on various hematological and biochemical parameters.

METHODS

For the measurement of carbamazepine and CBZE levels, a validated LC-MS / MS method was developed. Serum carbamazepine levels of patients were measured by AbSciex API 3200 LC-MS / MS and Beckman Coulter Emit® 2000 immunoassay. Biochemical, hematological parameters, and hormone levels were measured by Beckman-Coulter AU 5800 (Beckman Coulter, Brea, USA), Beckman Coulter LH 780 (Beckman Coulter, Miami, FL, USA), and Cobas 6000 (Roche Diagnostics, Germany) analyzers, respectively.

RESULTS

The imprecision values for all analytes were less than 7.0 %. The correlation coefficient between the methods was 0.981 (95 % confidence interval: 0.975 to 0.985). Linear regression analysis demonstrated highly significant associations of carbamazepine concentrations with albumin (B = -0.300, p = 0.040), calcium (B = -0.262, p = 0.004), phosphorus (B = -0.241, p = 0.022), WBC (B = -0.288, p = <0.001), PLT (B = -0.236, p = 0.003), RBC (B = -0.257, p = 0.001), NEU% (B = -0.289, p = <0.001), LYM% (B = -0.268, p = 0.001), D vitamini (B = -0.344, p = 0.006) levels.

CONCLUSIONS

A robust, rapid, and simple method has been developed. Our study revealed that carbamazepine and its metabolite have a significant correlation and likely impact on bone metabolism, blood cell counts, serum protein, albumin levels, and electrolyte concentrations.

An explorative literature review of the multifactorial causes of osteoporosis in epilepsy

PURPOSE

Patients with epilepsy have a greatly increased risk of osteoporosis and fractures. The literature is diverse and contradictory when dealing with the underlying pathophysiological mechanisms. Consequently, the purpose of this review was to shed light on the multifactorial causes behind the increased occurrence of metabolic bone disease in patients with epilepsy and to identify areas for future research.

METHODS

A review of the literature was performed searching PubMed with relevant Medical Subject Headings MeSH terms. The results of the search were evaluated for relevance to the review based on the title and abstract of the publication. Publications in language other than English and publications pertaining only pediatric patients were excluded. For all studies, included reference lists were evaluated for further relevant publications. In total, 96 publications were included in this explorative review.

RESULTS

The high occurrence of metabolic bone disease in patients with epilepsy is multifactorial. The causes are the socioeconomic consequences of having a chronic neurological disease but also adverse effects to antiepileptic drug treatment ranging from interference with calcium and vitamin D metabolism to hyponatremia-induced osteoporosis.

CONCLUSION

The literature supports the need for awareness of bone health in patients with epilepsy. The pathophysiological mechanisms are many and various wanting for further research in the less well-characterized areas. Furthermore, great responsibility rests on the healthcare professionals in implementing comprehensive patient care and in assuring bone protective measures in clinical practice to prevent bone loss in patients with epilepsy.

Effect of Long-term Carbamazepine Therapy on Bone Health

Introduction:

Recent research reported that prolonged use of AET is associated with changes in bone metabolism, with consequent reduction in bone mineral density (BMD) and increased risk of fractures.

Objectives:

Therefore, the aim of our study was to investigate the effects of carbamazepine on serum levels of 25 -hydroxyvitamin D and on biomarker of bone formation and resorption (serum levels of osteocalcin).

Material and methods:

We measured serum levels of 25-OHD and osteocalcin (OCLN) in normal controls (n=30) and in epilepsy patients taking carbamazepine (CBZ) (n=50) in monotherapy for a period of at least twelve months. For each participant, mineral density (BMD) was evaluated by dual-energy X-ray absorptiometry method.

Results:

The average value of vitamin D in serum was significantly lower in CBZ group than in control group (Vit D 17.03+12.86 vs. 32.03+6.99, p=0.0001). The average value of osteocalcin in serum was significantly higher in CBZ group than in control group (26.06+10.78 vs. 19.64+6, 54, p=0.004).BMD value in CBZ group was significantly lower than in control group (T. score CBZ: 0.08+1.38 vs. T. score control: 0.73+ 1.13, p=0.031; Z score CBZ:-0.05+1.17 vs. Z. score control: 0.55+0.79, p=0.015).

Conclusion:

AEDs are associated with bone disease, as evidenced by biochemical abnormalities and decreased BMD. Patients on long-term antiepileptic therapy, especially with enzyme-inducing agents, could benefit of routine measurement of biochemical markers of bone turnover, and BMD measurement as part of osteoporosis investigation.

Vitamin D in epilepsy: vitamin D levels in epilepsy patients, patients on antiepileptic drug polytherapy and drug-resistant epilepsy sufferers

The objective of this study was to assess vitamin D levels in epileptic patients and to compare its serum levels in patients on antiepileptic monotherapy and polytherapy. We analyzed the serum 25-hydroxy (25-OH) vitamin D levels in 98 consecutive subjects (43 epileptic patients and 55 non-epileptics). Factors influencing its serum levels such as degree of sun exposure, physical activity and dietary intake were taken into consideration. Overall, 41% had deficient, 49% had insufficient and 9% had sufficient levels of serum vitamin D. Elderly individuals (>60 years) and people employed in offices and schools had lower blood vitamin D levels. Across both the sexes, epileptic patients and non-epileptics, epileptic patients on monotherapy and polytherapy and patients with drug-responsive and -resistant seizures, there were no significant differences in serum 25-OH vitamin D levels. Our study shows that people with epilepsy suffer with vitamin D deficiency along with their normal peers.

Effects of antiepileptic drugs on bone health and growth potential in children with epilepsy

BACKGROUND

Bone health may be impaired in children with epilepsy.

OBJECTIVES

Our objective was to characterize bone mineral density (BMD) and bone growth in children receiving antiepileptic drugs (AEDs) and to assess the effects of co-morbidity, vitamin D deficiency, and type of drugs used.

DATA SOURCES

Data were sourced from PubMed, Embase, and Web of Science.

ELIGIBILITY CRITERIA

Cross-sectional, cohort, case-control, or randomized controlled trials reporting BMD or parameters of bone growth.

PARTICIPANTS

Children with epilepsy compared with controls.

INTERVENTIONS

AEDS or ketogenic diet.

STUDY APPRAISAL

The studies were evaluated by one author.

SYNTHESIS METHODS

Studies were categorized as reporting reduced BMD or not at any skeletal site as outcome. A logistic regression was performed for age, percent boys, study design, type of AED, co-morbidity or not, and signs of vitamin D deficiency/osteomalacia or not.

RESULTS

Carbamazepine and valproate were analyzed as monotherapy in 11 studies, and for both drugs a limited decrease in BMD seemed present. For oxcarbazepine, levetiracetam, phenytoin, phenobarbital, and topiramate, only one study with monotherapy was found for each drug, none of which reported decreased bone density. Polytherapy with AEDs seemed to be associated with a larger decrease in bone density than was monotherapy. Although few studies were available on bone growth, these did indicate that bone growth may be impaired among users of AEDs. Ketogenic diet may be associated with decreased bone density. The main determinant of normal BMD was absence of vitamin D deficiency/osteomalacia.

LIMITATIONS

The studies differed in skeletal sites studied and most were cross-sectional. No head-to-head comparisons of AEDs were performed. Children treated with polytherapy or ketogenic diet may have more complicated and severe disease than those treated with monotherapy. The underlying cause of epilepsy and vitamin D deficiency may contribute to impaired bone growth and density.

CONCLUSIONS

Reduced bone density, impaired bone growth, and vitamin D deficiency may be seen in children treated with drugs against epilepsy.

IMPLICATIONS

Measures to correct vitamin D deficiency, calcium intake should be taken.

The problem of osteoporosis in epileptic patients taking antiepileptic drugs

INTRODUCTION

Epilepsy is a common neurological disorder associated with recurrent seizures. Therapy with antiepileptic drugs (AEDs) helps achieve seizure remission in approximately 70% of epileptic patients. Treatment with AEDs is frequently lifelong and there are reports suggesting its negative influence on bone health. This is especially important in terms of general occurrence of osteoporosis, affecting over 50 million people worldwide.

AREAS COVERED

This study refers to two main groups of AEDs: hepatic enzyme inducers (carbamazepine, oxcarbazepine, phenobarbital, phenytoin, primidone and topiramate) and non-inducers (clobazam, clonazepam, ethosuximide, gabapentin, lacosamide, lamotrigine, levetiracetam, pregabalin, tiagabine, valproate, vigabatrin and zonisamide). Some reports indicate that enzyme inducers may exert a more negative influence on bone mineral density (BMD) compared to non-inducers. Bone problems may appear in both sexes during AED therapy, although women are additionally burdened with postmenopausal osteoporosis. Supplementation of vitamin D and calcium in patients on AEDs is recommended.

EXPERT OPINION

Apart from enzyme inducers, valproate (an even enzyme inhibitor) may also negatively affect BMD. However, the untoward effects of AEDs may depend upon their doses and duration of treatment. Although the problem of supplementation of vitamin D and calcium in epileptic patients on AEDs is controversial, there are recommendations to do so.

Neuroendocrinological aspects of epilepsy: important issues and trends in future research

Neuroendocrine research in epilepsy focuses on the interface among neurology, endocrinology, gynecology/andrology and psychiatry as it pertains to epilepsy. There are clinically important reciprocal interactions between hormones and the brain such that neuroactive hormones can modulate neuronal excitability and seizure occurrence while epileptiform discharges can disrupt hormonal secretion and promote the development of reproductive disorders. An understanding of these interactions and their mechanisms is important to the comprehensive management of individuals with epilepsy. The interactions are relevant not only to the management of seizure disorder but also epilepsy comorbidities such as reproductive dysfunction, hyposexuality and emotional disorders. This review focuses on some of the established biological underpinnings of the relationship and their clinical relevance. It identifies gaps in our knowledge and areas of promising research. The research has led to ongoing clinical trials to develop hormonal therapies for the treatment of epilepsy. The review also focuses on complications of epilepsy treatment with antiepileptic drugs. Although antiepileptic drugs have been the mainstay of epilepsy treatment, they can also have some adverse effects on sexual and reproductive function as well as bone density. As longevity increases, the prevention, diagnosis and treatment of osteoporosis becomes an increasingly more important topic, especially for individuals with epilepsy. The differential effects of antiepileptic drugs on bone density and their various mechanisms of action are reviewed and some guidelines and future directions for prevention of osteoporosis and treatment are presented.

The effect of oxcarbazepine on bone metabolism

OBJECTIVE

Long term use of several antiepileptic drugs is known to cause alteration in bone metabolism. Therefore, we investigated the effect of new antiepileptic drug, oxcarbazepine, on bone metabolism.

METHODS

Twenty eight patients who were on oxcarbazepin therapy (18 female, 10 males; mean age: 27.82 +/- 10.98 years (range: 15-45)) with no additional antiepileptic drug use history in one year period prior to the study and 28 control subjects were involved in the study. Measurement of calcium, phosphate, alkaline phosphatase and Vitamin D3 levels and bone density measurements with DEXA method were performed in patient and age-matched control groups. The baseline parameters were compared with the control group and with those measured at the end of one year.

RESULTS

The biochemical (calcium, phosphate, alkaline phosphatase and Vitamin D3) parameters and densitometry values after one year of therapy were not different than the baseline values indicating that those were not affected by the therapy (P > 0.05).

CONCLUSIONS

In previous studies, anticonvulsant drugs that induce enzymes increase bone degradation by causing vitamin D deficiency. According to the results of this study, oxcarbazepin with little effect on enzyme induction was shown not to affect bone mineral metabolism.

Bone health in young women with epilepsy after one year of antiepileptic drug monotherapy

OBJECTIVE

Antiepileptic drugs (AEDs) may have adverse effects on bone mineral density (BMD) and metabolism. We previously reported biochemical evidence of increased bone turnover in premenopausal women with epilepsy on phenytoin monotherapy compared with those on carbamazepine, lamotrigine, and valproate. We therefore hypothesized that rates of bone loss would be higher in young women treated with phenytoin.

METHODS

Ninety-three premenopausal women with epilepsy receiving a single AED (carbamazepine, lamotrigine, phenytoin, or valproate) participated. Subjects completed nutritional and physical activity questionnaires. Biochemical indices of bone and mineral metabolism and BMD of the proximal femur and lumbar spine were measured at baseline and 1 year.

RESULTS

Participants reported high calcium intake (>1,000 mg/day) and were physically active. Significant loss (2.6%) was seen at the femoral neck in the phenytoin group. BMD remained stable in the other AED groups. Bone turnover markers and calciotropic hormones were unchanged after 1 year in all groups except for a significant decline in urine N-telopeptide in the phenytoin group. In women receiving phenytoin, lower serum 25-hydroxyvitamin D concentrations were associated with higher parathyroid hormone, bone alkaline phosphatase, and urine N-telopeptide levels, a biochemical pattern consistent with secondary hyperparathyroidism and increased remodeling.

CONCLUSION

In this study, young women treated with phenytoin had significant femoral neck bone loss over 1 year. In contrast, those treated with carbamazepine, lamotrigine, and valproate did not have detectable adverse effects on bone turnover or bone mineral density. These results raise concerns about the long-term effects of phenytoin monotherapy on bone in young women with epilepsy.

Antiepileptic drugs and bone metabolism

Anti-epileptic medications encompass a wide range of drugs including anticonvulsants, benzodiazepines, enzyme inducers or inhibitors, with a variety effects, including induction of cytochrome P450 and other enzyme, which may lead to catabolism of vitamin D and hypocalcemia and other effects that may significantly effect the risk for low bone mass and fractures. With the current estimates of 50 million people worldwide with epilepsy together with the rapid increase in utilization of these medications for other indications, bone disease associated with the use of anti-epileptic medications is emerging as a serious health threat for millions of people. Nevertheless, it usually goes unrecognized and untreated. In this review we discuss the pathophysiologic mechanisms of bone disease associated with anti-epileptic use, including effect of anti-epileptic agents on bone turnover and fracture risk, highlighting various strategies for prevention of bone loss and associated fractures a rapidly increasing vulnerable population.

Vitamin D Levels and Bone Turnover in Epilepsy Patients Taking Carbamazepine or Oxcarbazepine

PURPOSE

Evidence suggests that enzyme-inducing antiepileptic drugs (AEDs) may decrease serum 25-hydroxyvitamin D (25-OHD) levels and increase bone turnover. We sought to determine whether these are affected by treatment with carbamazepine (CBZ) or oxcarbazepine (OXC).

METHODS

We measured serum levels of 25-OHD, parathyroid hormone (PTH), osteocalcin (OCLN), bone alkaline phosphatase (BAP), and urinary N-telopeptides of type I collagen cross-links (NTX) in normal controls (n=24) and in epilepsy patients taking CBZ (n=21) or OXC (n=24) in monotherapy. CBZ patients were subsequently switched overnight to OXC monotherapy, and after 6 weeks, the tests were repeated.

RESULTS

25-OHD levels were lower in each drug-treated group (OXC, 19.4+/-2.3 pg/ml; CBZ, 20.4+/-2.4) than in the controls (27.5+/-2.8) (ANOVA, p=0.052). This difference was significant for the OXC group (p<0.05). PTH, BAP, and NTX did not differ significantly among groups. OCLN levels were somewhat elevated in the OXC group (2.79+/-0.47 ng/ml) and more clearly and significantly elevated in the CBZ group (3.63+/-0.36) compared with controls (2.38+/- 0.41) (p=0.053). Because the data were very similar between OXC and CBZ groups, they were combined to increase statistical power. The combined drug-treatment group had significantly higher BAP (p=0.02) and lower 25-OHD (p=0.015) than did controls. The latter remained significant even after accounting for the confounding effects of age on 25-OHD levels (p<0.05). No significant differences were found after CBZ patients were switched to OXC.

CONCLUSIONS

Epilepsy patients taking OXC or CBZ have significantly lower 25-OHD than do normal controls, with a pattern of changes in other bone biomarkers suggestive of secondary hyperparathyroidism. It may be prudent for patients taking CBZ or OXC to be prescribed 25-OHD replacement.

Induction of endogenous pathways by antiepileptics and clinical implications

The aim of this study was to review modifications of the endogenous pathways (e.g. enzyme elevations, normal body constituent depletion or higher formation/excretion of endogenous metabolites) which could be ascribed to enzyme induction by antiepileptic drugs (AEDs). Information on older (e.g. phenobarbital, phenytoin and carbamazepine) and newer drugs (where information is available) is discussed together with clinical implications. The enzymes involved in the endogenous pathways and induced by the AEDs will not be limited to the hepatic microsomal enzymes; extrahepatic enzymes and/or enzymes present in other subcellular fractions will also be discussed, if pertinent. The induction of endogenous pathways by AEDs has been taken into account in the past, but much less emphasis has been given compared with the extensive literature on induction by AEDs of the metabolism of concomitantly administered drugs, either of the same or of different classes. Not all of the endogenous pathways examined and induced by AEDs appear to result in serious clinical consequences (e.g. induction of hepatic ALP, increased excretion of d-glucaric acid or of 6 beta-hydroxycortisol). In some cases, induction of some pathways (e.g. increase of high-density lipoprotein cholesterol or of conjugated bilirubin) might even be a beneficial side-effect, however enzyme induction is considered rather a detrimental aspect for an AED, as induction is generally a broad and a non-specific phenomenon. The new AEDs have generally less induction potential than the older agents. Yet some (felbamate, topiramate, oxcarbazepine and lamotrigine) have the potential for inducing enzymes, whereas others (levetiracetam, gabapentin and vigabatrin) appear to be completely devoid of enzyme inducing characteristics, at least as far as the enzymes investigated are concerned.

Early alteration in bone metabolism in epileptic children receiving carbamazepine monotherapy owing to the induction of hepatic drug-metabolizing enzymes

The purpose of this study was to investigate, by a prospective, self-controlled method, whether early treatment with carbamazepine monotherapy can alter bone metabolism in ambulatory epileptic children with adequate sun exposure, based on the determination of total serum alkaline phosphatase and its bone isoenzyme activities. Serum total alkaline phosphatase and its bone, liver, and intestinal isoenzyme activities were evaluated in 22 epileptic ambulatory children (13 males and 9 females, aged from 5 to 12 years) before and at 3, 6, and 12 months of carbamazepine monotherapy. Serum concentrations of other biochemical markers of bone and liver metabolism, such as calcium, phosphorus, magnesium, gamma-glutamyltransferase, alanine aminotransferase, aspartate aminotransferase, and lactate dehydrogenase, were also measured in the study participants before and at 6 and 12 months of treatment. Carbamazepine was prescribed at normal dosages (16.4-20 mg/kg/day). Serum total alkaline phosphatase activities were significantly increased at 3 (P = .000), 6 (P = .024), and 12 (P = .037) months of treatment; serum bone alkaline phosphatase activities at 3 (P = .000), 6 (P = .008), and 12 (P = .017) months of treatment; and serum liver alkaline phosphatase activities at 3 (P = .000), 6 (P = .049), and 12 (P = .008) months of treatment, whereas serum intestinal alkaline phosphatase isoenzyme activity was significantly increased only at 3 months of treatment (P = .035). Serum gamma-glutamyltransferase activities were also significantly increased at 6 (P = .000) and 12 (P = .000) months of treatment. No significant changes in the concentrations of serum calcium, phosphorus, magnesium, alanine aminotransferase, aspartate aminotransferase, and lactate dehydrogenase were noted at 6 and 12 months of treatment. There was a significant correlation between serum gamma-glutamyltransferase activities and serum total alkaline phosphatase activities (r = .689, P = .000 at 6 months; r = .493, P = .020 at 12 months), bone alkaline phosphatase activities (r = .700, P = .000 at 6 months; r = .466, P = .029 at 12 months), and liver alkaline phosphatase activities (r = .427, P = .047 at 6 months; r = .425, P = .048 at 12 months). These findings indicate that ambulatory children who receive carbamazepine monotherapy, even when residing in a country with adequate sunlight, can have their bone metabolism altered early in the course of treatment, as indicated by the elevated activities of serum bone alkaline phosphatase isoenzyme. This early alteration in bone metabolism is probably due to the hepatic enzyme-inducing character of carbamazepine.

Effect of carbamazepine and valproate on bone mineral density

The objective of this study was to examine the effect of carbamazepine and valproate monotherapy on bone mineral density in children. Femoral neck area bone mineral density was measured by dual-energy x-ray absorptiometry in 31 healthy children and 33 children with idiopathic epilepsy treated with either carbamazepine (n = 17) or valproate (n = 16) for more than 6 months. There were no significant differences between the control and study patients in age, height, weight, and physical activity. No patient had dietary restrictions or neurologic impairment. Serum levels (as mean +/- S.D.) of valproate and carbamazepine were 53.75 +/- 23.94 microg/mL and 6.26 +/- 2.00 microg/mL, respectively, and the duration of treatment for each drug was 24.38 +/- 10.58 months and 31.76 +/- 16.33 months, respectively. Calcium intake in the diet was similar in both the control and study groups. In the valproate-treated group, 25% of the patients were hypocalcemic, 6% had elevated alkaline phosphatase levels, and 50% were hypophosphatemic. In the carbamazepine-treated group, 17.6% of the patients were hypocalcemic and 35.3% were hypophosphatemic. Children treated with valproate had 31.9% reduction in bone mineral density at the femoral neck area (P < 0.05); the 20% reduction in bone mineral density in this anatomic location in carbamazepine-treated children was not significant. In conclusion, valproate monotherapy, but not carbamazepine therapy, significantly reduces femoral neck area bone mineral density in children with idiopathic epilepsy.

Antiepileptic drugs and reduced bone mineral density

There is a growing interest in recognizing the association between antiepileptic drugs and reduced bone mineral density. Although the literature regarding this association has been available for more than three decades, the management of this complication remains unclear. We review the relevant literature regarding antiepileptic drugs and reduction in bone mineral density with the aim of developing some guidelines for practical management of this problem. This review focuses on the mechanism of antiepileptic drug-induced bone loss, its recognition, and its management.

Epilepsy and bone health in adults

Adults taking antiepileptic drugs (AEDs) have an augmented risk for osteopenia and osteoporosis because of abnormalities of bone metabolism associated with AEDs. The increased fracture rates that have been described among patients with epilepsy may be related both to seizures and to AEDs. The hepatic enzyme-inducing AEDs phenytoin, phenobarbital, and primidone have the clearest association with decreased bone mineral density (BMD). Carbamazepine, also an enzyme-inducing drug, and valproate, an enzyme inhibitor, may also adversely affect bone, but further study is needed. Little information is available about specific effects of newer AEDs on bone. Physicians are insufficiently aware of the association between AEDs and bone disease; a survey found that fewer than one-third of neurologists routinely evaluated AED-treated patients for bone disease, and fewer than 10% prescribed prophylactic calcium and vitamin D. Physicians should counsel patients taking AEDs about good bone health practices, and evaluation of bone health by measuring BMD is warranted after 5 years of AED treatment or before treatment in postmenopausal women.

Treatment of anticonvulsant drug-induced bone disease

Although the pathophysiology of bone disease in patients treated with anticonvulsant drugs may vary, most affected patients have increased bone remodeling rather than decreased mineralization. Milder cases may show high bone turnover without significant loss of cortical or trabecular bone. Cases of intermediate severity may exhibit the characteristic features of a high-turnover osteopenia/osteoporosis, but some patients with severe bone disease may manifest the features of an osteomalacic disorder. Prophylactic vitamin D supplementation at doses up to 2000 IU/day can be recommended for all patients on initiation of anticonvulsant therapy. A calcium intake of 600-1000 mg/day should also be ensured. If an osteopenic/osteoporotic disorder exists, treatment with 2000-4000 IU/day vitamin D is appropriate. Vitamin D doses of 5000-15,000 IU/day may be needed to treat osteomalacia. Conventional treatment with bisphosphonates may be needed when the response to vitamin D is inadequate. However, routine use of bisphosphonates in patients receiving long-term anticonvulsant therapy cannot at present be recommended.

Increased bone turnover in prepubertal, pubertal, and postpubertal patients receiving carbamazepine

PURPOSE

To study the markers of bone turnover in epilepsy patients in the different stages of the pubertal growth before and after the beginning of carbamazepine (CBZ) monotherapy.

METHODS

We have investigated bone turnover in 60 epilepsy patients treated with CBZ. They were stratified according to pubertal stage and compared with a control group of 60 sex- and age-matched healthy children.

RESULTS

After 2 years of therapy, we found higher values of the serum markers of bone formation [bone alkaline phosphatase (bone ALP), osteocalcin (OC), carboxy-terminal propeptide of type I procollagen (PICP), amino-terminal propeptide of type III procollagen (PIIINP)], and of bone resorption [carboxy-terminal telopeptide of type I collagen (ICTP) and the urinary cross-linked N-telopeptides of type I collagen (NTX)] in patients than in control subjects, in presence of a normal vitamin D metabolism.

CONCLUSIONS

CBZ induces an increase of bone formation and of bone resorption that seems to be independent of the pubertal stage.

Analysis of the musculoskeletal system in children and adolescents receiving anticonvulsant monotherapy with valproic acid or carbamazepine

OBJECTIVE

To examine bone development in children and adolescents who have uncomplicated idiopathic epilepsy and had received monotherapy with carbamazepine or valproic acid for at least 1 year.

METHODS

Thirty-nine patients from 6 to 19 years of age (18 girls) were studied. Total bone mineral content (BMC) and trabecular volumetric bone mineral density were measured at the distal radius using peripheral quantitative computed tomography. Maximum isometric grip force was determined with a standard dynamometer. Alkaline phosphatase activity and deoxypyridinoline (a marker of bone resorption) were assessed in serum and urine, respectively.

RESULTS

Trabecular volumetric bone mineral density was significantly decreased in the entire group (z score mean +/- standard deviation: -0.62 +/- 1.04) and in the subgroup using valproic acid (-0.75 +/- 1.18). In the carbamazepine subgroup, there was a similar but nonsignificant trend (-0.50 +/- 0.90). Total BMC and isometric maximum grip force were normal in the entire study population (0.10 +/- 1.22) and in the 2 subgroups. The relationship between BMC and grip force was similar between patients and healthy participants. Urinary levels of deoxypyridinoline were significantly elevated above normal in the whole study population (1.35 +/- 2.00) and in both the valproic acid and the carbamazepine subgroups.

CONCLUSIONS

Bone turnover can be increased, but bone mass is adequate in children and adolescents who have uncomplicated idiopathic epilepsy and who receive monotherapy with carbamazepine or valproic acid.

Adverse effects of antiepileptic drugs on bone structure: epidemiology, mechanisms and therapeutic implications

Antiepileptic drugs (AEDs) were first associated with disorders of bone in both adults and children in the late 1960s. The most severe manifestations of these disorders are osteopenia/osteoporosis, osteomalacia and fractures. Bone disease has been described in several groups of patients receiving AEDs. Groups identified as being more vulnerable to AED-associated bone disease include institutionalised patients, postmenopausal women, older men and children. Radiological and histological evidence of bone disease is found in patients taking AEDs. Numerous biochemical abnormalities of bone metabolism have also been described. The severity of bone and biochemical abnormalities is thought to correlate with the duration of AED exposure and the number of AEDs used. In monotherapy, the AEDs most commonly associated with altered bone metabolism are phenytoin, primidone and phenobarbital (phenobarbitone). To date there have been no reports of altered bone metabolism in individuals receiving the newer anticonvulsants (specifically lamotrigine, topiramate, vigabatrin and gabapentin). The mechanisms of AED-associated bone disease are not clearly elucidated; however, several theories have been proposed to explain the link. No definitive guidelines for evaluation or treatment have yet been determined.

Osteoporosis in children and adolescent girls: case report of idiopathic juvenile osteoporosis and review of the literature

The diagnosis and treatment of osteoporosis is an important aspect of gynecologic training and practice. Idiopathic juvenile osteoporosis (IJO) is a rare disease of children and adolescents that resolves after the onset of puberty. A case report is presented and current methods of diagnosis and treatment of IJO are discussed as well as the differential diagnosis. A MEDLINE search was performed of the following terms: idiopathic juvenile osteoporosis, pediatric osteoporosis, adolescent osteoporosis, bisphosphonates pediatric adolescent, and pregnancy osteoporosis, and references from bibliographies of selected papers were used as well. All papers in English, French, and German are considered in this review. There were 114 papers selected as relevant to the topic. Data relevant to the diagnosis, pathogenesis, methods of imaging, laboratory evaluation, differential diagnosis, and treatment of IJO are presented. IJO is a diagnosis of exclusion in the pediatric and adolescent patient with osteoporosis. Although bone density gradually improves after the onset of puberty, treatment of currently affected children and adolescents involves activity restriction, calcium, vitamin D, and bisphosphonate therapy. Future reproductive concerns are discussed and areas requiring additional study are reviewed.

TARGET AUDIENCE

Obstetricians & Gynecologists, Family Physicians

LEARNING OBJECTIVES

After completion of this article, the reader will be able to describe the condition idiopathic juvenile osteoporosis, compare the clinical features of this condition to other similar conditions, outline the diagnostic workup of a child with this condition, and list the potential therapeutic options for a patient with idiopathic juvenile osteoporosis.

Hypocalcemia in children: pathogenesis and management

Hypocalcemia can be devastating if unrecognized. Neuromuscular dysfunction occurs in severe cases. A review and an update on the topic may assist general pediatricians. The authors provide a general overview of pathogenesis and management of hypocalcemia in children.

Effect of antiepileptic drugs on bone mineral density in children between ages 6 and 12 years

We assessed the effects of sodium valproate and carbamazepine monotherapy on bone mineral density (BMD) in children. BMD at the lumbar vertebrae (L1-L4) and radius-ulna was measured by the dual-energy x-ray absorptiometry (DEXA) method in 19 children (9 girls, 10 boys) with uncomplicated epilepsy and in 57 healthy children (28 girls, 29 boys), between the ages of 6 and 12 years. The study patients had been receiving either sodium valproate (n = 13) or carbamazepine (n = 6) monotherapy for more than 6 months. There were no significant differences between the control and study patients in age, height, weight, physical activity, or of serum concentrations of calcium, phosphate, and transaminases (aspartate aminotransferase, alanine aminotransferase). However, the serum alkaline phosphatase concentration was greater in the patient group as compared with the control group. BMD values were lower in girl patients (L1-L4; 0.497 +/- 0.08 vs 0.566 +/- 0.07 g/cm2, p < 0.05), but not in boys (0.534 +/- 0.06 vs 0.530 +/- 0.08 g/cm2). While BMD reduction was 8% in valproate therapy (midregion of radius-ulna; 0.287 +/- 0.03 vs 0.312 +/- 0.04 g/cm2, p < 0.04), it was reduced only 4.5% in the carbamazepine-treated group (0.298 +/- 0.01 vs 0.312 +/- 0.04 g/cm2, statistically not significant), although the mean durations of monotherapy with valproate (1.8 +/- 0.7 years) and carbamazepine (1.7 +/- 0.8 years) were similar. Thus decreased bone mineralization was observed in children with epilepsy, treated with sodium valproate even though treatment was for a rather short time.

Evaluation of bone mineral density in children receiving antiepileptic drugs

The effects of the valproic acid and carbamazepine monotherapies on bone mineral density were evaluated. Bone mineral density was measured in 53 children with primary epilepsy taking either valproic acid (n = 25) or carbamazepine (n = 28) for longer than 1 year and in a healthy control group (n = 26) by the dual-energy x-ray absorptiometry method at L2-L4 levels of lumbar vertebrae. The mean serum levels of valproic acid and carbamazepine were 66 +/- 2.2 microg/mL and 7.0 +/- 9.3 microg/mL, respectively, and the mean duration of treatment for each drug was 2.4 +/- 0.2 years and 2.6 +/- 0.5 years, respectively. Calcium intakes in diet were similar in both the control and study groups. The serum levels of calcium and phosphorus in all groups were normal. Bone mineral density values of both valproic acid and carbamazepine groups were not statistically different from that of the control group (P > 0.05).

Vitamin D levels in noninstitutionalized children with cerebral palsy

Calcitriol (1,25-dihydroxy vitamin D) is an important hormone in calcium and phosphate metabolism. Levels of calcitriol and its precursor, 25-hydroxy vitamin D (calcidiol), were measured in a heterogeneous group of 125 noninstitutionalized children and adolescents with spastic cerebral palsy. Levels of each were correlated with: (1) clinical factors including mobility, prior fracture, and use of anticonvulsants; (2) nutrition and growth parameters including skinfolds, body mass index, and use of vitamin supplements; and (3) other serum analyses including osteocalcin as a marker of bone formation, calcium, and alkaline phosphatase. Levels of calcidiol and calcitriol did not correlate with any of the various clinical, nutritional, or growth parameters examined. The prevalence of low (< 10 ng/mL) levels of calcidiol was significant (19%), and dependent on the season of the year in which the level was measured. In contrast, less than 2% of the patients were found to have a low (< 20 pg/mL) level of calcitriol and the mean was comparable to normal pediatric subjects. Levels of calcitriol are maintained in noninstitutionalized children with cerebral palsy despite anticonvulsants, poor nutrition, and calcidiol levels that vary greatly with the seasons.

[Carbamazepine and vigabatrin in epileptic pregnant woman and side effects in the newborn infant]

BACKGROUND

Carbamazepine (Tegretol) is frequently prescribed to pregnant epileptic women. Various congenital malformations constitute the most described side-effects in their newborns.

CASE REPORTS

Case 1. Esteban was born by caesarean section at 39 weeks of gestation, weighing 3,860 g. His Apgar score was 8, 9, 10 at 1, 3 and 5 minutes. His mother was given phenobarbital until 1.5 months of pregnancy then carbamazepine 400 mg LP x 2/day, raised to 600 mg LP x 2/day at the 25th week of gestation because of epileptic crisis. The newborn was transferred at day 4 for drowsiness, mild jaundice, persistent vomiting and bouts of hypotonia/hypertonia, tremors and hyperexcitability. His plasma Tegretol level was 5.9 micrograms/mL and severe hypocalcemia (1.35 mmol/L) was noted. Hypocalcemia disappeared within 48 hours and gastric and neurologic troubles by day 6. The patient left the hospital at day 14. Case 2. Matheo, Esteban's brother, was born by caesarean section after 39 weeks of gestation, weighing 3,210 g. His Apgar score was 9, 10, 10 at first, third and fifth minutes. The mother's anti-epieptic treatment associated carbamazepine LP 400 mg x 3/day and vigabatrin four tablets of 500 mg/d until the 6th month of pregnancy and five tablets by day thereafter. The newborn presented vomiting from the first feeding; tremors were noted on day 2. His plasma Tegretol level was 5.7 micrograms/mL (N = 4-8 micrograms/mL) and the baby was transferred. Upon arrival, persistent vomiting and succession of hypotonia/hypertonia with intermittent opisthotonos were noted. Blood and urine tests showed: low calcemia (2.19 mmol/L), negative Brand reaction and DNPH test, normal urinary and blood amino acid chromatography. The course was spontaneously favourable and the child went home at day 11.

CONCLUSION

Newborns of epileptic mothers treated with carbamazepine and/or vigabatrin during pregnancy should be placed under clinical observation during their first postnatal week. Calcemia monitoring is suggested for infants whose mothers were not supplemented with vitamin D during pregnancy. With a follow up of respectively 26 and 7 months, both brothers have normal milestones, confirming the transitory and benign character of reported side-effects.

Effect of carbamazepine and valproate on bone mineral density

OBJECTIVE

To examine the effect of carbamazepine and valproate monotherapy on bone mineral density in children.

METHODS

Axial (second, third, and fourth lumbar vertebrae) and appendicular (distal third of radius) bone mineral density was measured by dual-energy x-ray absorptiometry in 27 healthy children and 26 children with uncomplicated idiopathic epilepsy treated with either carbamazepine (n = 13) or valproate (n = 13) for more than 18 months. Control subjects and patients were similar with respect to age, race (all white), and geographic area, and had no dietary restrictions, neurologic impairment, or physical handicaps.

RESULTS

Subjects were seizure-free for more than 6 months on a regimen of carbamazepine or valproate therapy, and had mean serum trough levels of 6.88 +/- 2 micrograms/ml and 72.04 +/- 45.6 micrograms/ml, respectively. Dietary calcium intake was similar in control and treated groups. After correction for gender and age, children treated with valproate had a 14% (p = 0.003) and 10% (p = 0.005) reduction in bone mineral density at the axial and appendicular sites, respectively. The reduction in bone mineral density increased with the duration of valproate therapy. Carbamazepine did not significantly reduce bone mineral density.

CONCLUSION

Valproate montherapy, but not carbamazepine therapy, significantly reduces axial and appendicular bone mineral density in children with idiopathic epilepsy and may increase their risk of osteoporotic fractures.

Bone mineral density measured by dual-energy x-ray absorptiometry and novel markers of bone formation and resorption in patients on antiepileptic drugs

In patients on antiepileptic drugs, bone loss has been mainly demonstrated at radial sites using old technology and has been ascribed to drug-induced vitamin D deficiency rather than to any direct effects of the treatment on bone cells. We examined 38 epileptic patients (24 women and 14 men) aged 20-49 years who were using either carbamazepine or phenytoin or both. Bone mineral density (BMD) at the lumbar spine and three femoral sites was measured by dual-energy x-ray absorptiometry (DXA) and serum and urine markers of bone and mineral metabolism were determined. The latter included the C-terminal extension peptide of type I procollagen (PICP), a putative serum marker of bone formation, and the cross-linked carboxyl-terminal telopeptide of human type I collagen (ICTP), a novel serum marker of bone matrix degradation. In female patients on phenytoin, weight- and height-adjusted BMD was reduced at the femoral neck and the Ward's triangle (p < 0.05) but was at the control level in the other patient groups at all four measurement sites. Compared with controls, the serum concentrations of 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D were reduced by 26% (p < 0.01) and by 27% (p < 0.001) in female patients. These changes were independent of the therapy used. They were not present in male patients. For both genders the serum levels of vitamin D binding protein were normal. Both female and male patients had hypocalcemia, but women only showed hypocalciuria.(ABSTRACT TRUNCATED AT 250 WORDS)

A trial of discontinuation of barbiturates in patients with secondary generalized epilepsy

The vast majority of patients with secondary generalized epilepsy (SGE) were under polytherapy including barbiturates. We were able to completely withdraw barbiturates in 17 cases with a refractory course of SGE. Valproic acid (VPA) is considered as one of the best drugs for SGE. Barbiturates decrease the serum level of VPA and this may lead to a reduced efficacy of VPA. The dosage of VPA was adjusted to attain the level of 100-150 micrograms/ml. Barbiturates were then gradually decreased and finally discontinued. After six months of follow-up, 13 patients (76%) showed a reduced seizure frequency. Also, the physical and psychological conditions improved in a good number of cases. Barbiturates are not necessarily required in pharmacotherapy of SGE and may be safely withdrawn.

Anticonvulsant drugs and bone metabolism

The influence of chronic antiepileptic treatment on bone metabolism has been investigated in 52 adult epileptics, who had normal dietary intake, sunlight exposure and daily living activities. None of the patients had symptoms or signs suggestive of osteomalacia. Serum phosphate levels were significantly decreased and serum alkaline phosphatase levels were significantly increased in the patients compared with matched controls. Calcitonin values and bone mineral content, measured by single photon absorptiometry, were significantly lower among anticonvulsant users. Calcium metabolism impairment grossly correlated to the number of drugs concurrently used by the patient but not to the types, to the relative plasma concentrations or to the overall duration of the treatment. Our findings indicate that in ambulatory patients with adequate diet and outdoor activities in Italy present with clinically irrelevant impairment of bone metabolism.

Different metabolism of vitamin D2/D3 in epileptic patients treated with phenobarbitone/phenytoin

Serum concentrations of vitamin D metabolites were measured before and during treatment with either vitamin D2 or vitamin D3, 4000 IU per day for 24 weeks, in 22 epileptic outpatients receiving phenobarbitone/phenytoin. The serum concentration of total 1,25(OH)2D did not change during the treatment period in any of the treatment groups. On the other hand, in the vitamin D2 group, serum 25(OH)D2, total 25(OH)D, and 24,25(OH)2D increased significantly during the trial, whereas serum concentrations of the vitamin D3 metabolites were unchanged. In the vitamin D3 group, serum concentrations of the vitamin D3 metabolites increased significantly, whereas the vitamin D3 metabolite levels remained unchanged. However, vitamin D3 treatment resulted in a 2-4-fold greater increase in serum concentrations compared to vitamin D2 treatment. Treatment with vitamin D2 and vitamin D3 in the same dose in IU results in considerably different serum concentrations of the vitamin D metabolites.

Different metabolism of vitamin D2 and vitamin D3 in epileptic patients on carbamazepine

Serum concentrations of vitamin D metabolites were measured in 30 epileptic outpatients on monotherapy with carbamazepine before and during treatment with either vitamin D2 or vitamin D3, 4000 IU per day for 24 weeks. Vitamin D2 treatment increased the serum concentration of 25OHD2, but a corresponding decrease in 25OHD3 resulted in an unchanged serum value of total 25OHD. Vitamin D3 treatment increased the serum concentration of 25OHD3. The resulting serum level of 25OHD was consequently twice the level of that in the D2-treated group. The serum concentrations of the dihydroxy metabolites showed a similar difference between the 2 treatment groups. We conclude that treatment with vitamins D2 and D3 in the same doses produces considerably different serum concentrations of vitamin D metabolites. If the present findings can be extrapolated to normal subjects, it is important to consider more carefully which D-vitamin should be used, both with regard to therapy and supplementation.

Measurement of 25-hydroxyvitamin D3 and 25-hydroxyvitamin D2 in clinical settings

A quick and simple method for the selective measurement of 25-hydroxyvitamin D3 (25OHD3) and 25-hydroxyvitamin D2 (25OHD2) is described. It includes a rapid sample preparation technique and a combination of a selective radioimmunoassay for 25OHD3 and a competitive protein-binding assay using vitamin D-binding protein for the determination of total 25OHD, including 25OHD3 and 25OHD2. The method was compared with a procedure which include methanol/methylene chloride extraction and chromatography on Sephadex LH 20, and a procedure which includes HPLC and final quantification by u. v. detection. The methods were applied to three groups of patients in order to obtain information on how far assay procedures could be simplified for use in the clinical settings. It is concluded that the method described is applicable for following patients on vitamin D2 therapy. When groups of patients have to be compared, the mean values of the estimates are comparable, whether a simple method or a laborious method is used. Hence, the selection of assay method should take into account the clinical problem and the cost of the analysis.

Effect of vitamin D2 and D3 on bone-mineral content in carbamazepine-treated epileptic patients

In order to clarify whether carbamazepine causes disturbances in calcium and bone metabolism were examined the effect of vitamin D2 or D3 in 30 epileptic outpatients. They had been treated for at least 1 year with carbamazepine given as monotherapy. The local bone mineral in the forearms and the total bone mineral was measured before and during treatment with the vitamins (4000 IU/day) for 24 weeks. The bone mineral was not significantly different from controls before the study and it remained unchanged in both treatment groups during the study periods. Similarly, the biochemical indices of bone metabolism were virtually unchanged during the treatment period. We, thus, conclude that epileptic patients on carbamazepine monotherapy have normal bone metabolism.