[Osteomalacy induced by anticonvulsants. One case with a study of vitamin D metabolism]

A case of osteomalacia, with no cause apart from the ingestion of anti-convulsants, is reported. As was shown by a study with tritium labelled vitamin D, the metabolism of the latter was accelerated in this case in comparison with deficiency type osteomalacia. This lends support to the hypothesis that anti-convulsant medications, acting via a hepatic enzyme induction process, cause increased transformation of vitamin D into inactive metabolites, thus explaining a certain deficiency in vitamin D in treated epileptics, a deficiency state which requires treatment.