Osteomalacia with Long-term Anticonvulsant Therapy in Epilepsy

Dent, C. E.; Richens, A.; Rowe, Dorothy J.; Stamp, T. C. B.

doi:10.1136/bmj.4.5727.69

Cited by 396 publications

(155 citation statements)

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“…The production of vitamin D, by the skin, varies according to the season in regions that have greater latitude and production is less during autumn/winter. In these regions, exogenous sources of vitamin D are very important to maintain the daily vitamin needs of the normal population 8 and especially in the case of anticonvulsant users, where the necessity for this vitamin is greater, because the hepatic enzyme system activity increases the catabolism of this vitamin into inactive products 1,5 . Phenobarbital, phenytoin, primidone and carbamazepine increase the hepatic microsomal enzyme activity which accelerates the hydroxylation of vitamin D, as well as the catabolism of vitamin D from 25-hydroxycholecalciferol and 1,25-dihydroxycholecalciferol into inactive products leading to a reduction in vitamin reserves and increasing daily needs 9 .…”

Section: Discussionmentioning

confidence: 99%

“…Conclusões: Pacientes adultos, do sexo masculino, usuários crônicos de anticonvulsivantes, residentes em regiões ensolaradas, têm densidade mineral óssea e níveis plasmáticos de vitamina D normais. PALAVRAS-CHAVE: vitamina D, cálcio, anticonvulsivante, densidade mineral óssea.Alterations in calcium, vitamin D and bone tissue metabolism have been associated with the following drugs: phenobarbital, phenytoin, primidone and carbamazepine 1,2 . Alterations in the metabolism of calcium are generally very slight and subclinical, but clear cases of hypocalcemia could occur in 4% to 30% of individuals.…”

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“…Alterations in calcium, vitamin D and bone tissue metabolism have been associated with the following drugs: phenobarbital, phenytoin, primidone and carbamazepine 1,2 . Alterations in the metabolism of calcium are generally very slight and subclinical, but clear cases of hypocalcemia could occur in 4% to 30% of individuals.…”

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Bone mineral density, vitamin D and anticonvulsant therapy

Filardi

Guerreiro

Magna

et al. 2000

Arq. Neuro-Psiquiatr.

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-The aim of this study was to assess bone mineral density and vitamin D metabolism in patients on chronic anticonvulsant therapy. Methods: Sixty-nine men, outpatients on chronic anticonvulsant therapy, who had been treated for at least 5 years, were studied, comparing them to thirty healthy controls. Bone mineral density was measured as well as serum levels of calcium, ionized calcium, alkaline phosphatase, PTH, 25-hydroxycholecalciferol and 1,25-dihydroxycholecalciferol. Results: No differences in bone mineral density, serum levels of vitamin D and intact-PTH were observed between patients and controls. Bone mineral density was not associated with chronic anticonvulsant therapy. Conclusion: Those adult patients who were on chronic anticonvulsant therapy and who lived in low latitude regions had normal bone mineral density as well as vitamin D serum levels.KEY WORDS: vitamin D, calcium, anticonvulsant, bone mineral density. Densidade mineral óssea, vitamina D e terapia anticonvulsivanteRESUMO -O objetivo deste estudo foi avaliar a densidade mineral óssea e o metabolismo da vitamina D em usuários crônicos de anticonvulsivantes. Métodos: Foram estudados 69 pacientes ambulatoriais, masculinos, usuários crônicos de anticonvulsivantes por período mínimo de 5 anos e comparados a 30 controles normais. Foram efetuadas as medidas da densidade mineral óssea e dos níveis plasmáticos do cálcio, cálcio iônico, fosfatase alcalina, paratormônio, 25-hidroxi-colecalciferol e 1,25-di-hidroxi-colecalciferol. Resultados: Nenhuma diferença na densidade mineral óssea e nos níveis plasmáticos da vitamina D e paratormônio foram observadas entre os pacientes e os controles. A densidade mineral óssea não se mostrou associada ao uso crônico de anticonvulsivantes. Conclusões: Pacientes adultos, do sexo masculino, usuários crônicos de anticonvulsivantes, residentes em regiões ensolaradas, têm densidade mineral óssea e níveis plasmáticos de vitamina D normais. PALAVRAS-CHAVE: vitamina D, cálcio, anticonvulsivante, densidade mineral óssea.Alterations in calcium, vitamin D and bone tissue metabolism have been associated with the following drugs: phenobarbital, phenytoin, primidone and carbamazepine 1,2 . Alterations in the metabolism of calcium are generally very slight and subclinical, but clear cases of hypocalcemia could occur in 4% to 30% of individuals. The intensity of the clinical symptoms depends on many factors, such as: intake of vitamin D, exposure to the sun, physical activity, other diseases that interfere in vitamin D metabolism, the positive correlation of these manifestations with the type of drug, individual drug dosage, and period of exposure, as well as polytherapy 3,6 .This study, which was conducted to assess bone mineral density and vitamin D metabolism in a sample of the Brazilian epileptic population on chronic anticonvulsant therapy, was motivated by the fact that the intensity of alterations of vitamin D metabolism and bone mass was related not only to the chronic use of anticonvulsants but also to other vari...

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Bone mineral density, vitamin D and anticonvulsant therapy

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Guerreiro

Magna

et al. 2000

Arq. Neuro-Psiquiatr.

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“…Tests Anticonvulsant therapy for epilepsy has been associated with hypocalcaemia and osteomalacia, but the incidence of both is controversial. It has been suggested that patients on anticonvulsant therapy have an increased requirement for vitamin D because of induction of enzymes responsible for degradation of vitamin D to inactive metabolites (Dent et al, 1970;Hunter et al, 1971).…”

Section: ---------mentioning

confidence: 99%

Hypocalcaemia: Differential Diagnosis and Investigation

Paterson

1976

Ann Clin Biochem

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Hypocalcaemia accounts for many of the telephone inquiries made to the Department of Biochemical Medicine in Dundee. About half of these cases can be explained by hypoalbuminaemia; the causes of “true” hypocalcaemia are given in Table 1. Chronic renal failure is probably the most frequent cause of hypocalcaemia in Britain. In the world as a whole it is likely that vitamin D deficiency, causing rickets in children and osteomalacia in adults, is the commonest cause of hypocalcaemia.

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“…It is likely that 'anticonvulsant osteomalacia' is the result of such an effect (Dent, Richens, Rowe & Stamp, 1970;Lancet, 1972a (Blunt, De Luca & Schnoes, 1968), and this substance is then further hydroxylated in the kidneys to produce the biologically active metabolite, 1,25-dihydroxycholecalciferol (Fraser & Kodicek, 1970). Anticonvulsant drugs disturb the hepatic hydroxylation, possibly by inducing enzymes in collateral pathways, leading to the formation of inactive metabolites (Dent et aL, 1970;Hahn, Birge, Scharp & Avioli, 1972;Silver, Neal, Davies, Breckenridge & Thompson, 1972).…”

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Osteomalacia with Long-term Anticonvulsant Therapy in Epilepsy

Cited by 396 publications

References 9 publications

Bone mineral density, vitamin D and anticonvulsant therapy

Bone mineral density, vitamin D and anticonvulsant therapy

Hypocalcaemia: Differential Diagnosis and Investigation

The Clinical Consequences of Chronic Hepatic Enzyme Induction by Anticonvulsant Drugs

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