Delayed response to a alpha-hydroxycholecalciferol therapy in a case of hypoparathyroidism during anticonvulsant therapy.

A patient with idiopathic hypoparathyroidism and a six-year history of a convulsive disorder was treated with 1 alpha-hydroxycholecalciferol and anticonvulsants. The calcemic response to 1 alpha-hydroxycholecalciferol was incomplete. However, normocalcemia was later attained during treatment with dihydrotachysterol. This delayed response suggests that the anticonvulsant therapy interfered with the peripheral effect of the vitamin D metabolite.