Anticonvulsant Therapy-induced Alterations in Calcium Homeostasis

35 epileptic patients, aged 10 to 58 years (mean 23), who were taking anticonvulsant drugs were studied. The patients exhibited a 34% reduction in serum calcium levels, a 41 % increase in serum alkaline phosphatase activity and a slight but insignificant decrease in serum phosphate, compared to untreated controls. These changes appear to be related to the anticonvul­ sant drug taken, in the following order of decreasing importance: phenytoin + phenobarbital + carbamazepine; phenytoin + phenobarbital; phenytoin + carbamazepine,and phenobarbital + carbamazepine. It is possible that anticonvulsant drugs alter vitamin D metabolism which results in disturb­ ance of calcium homeostasis. Moreover these changes in serum calcium and alkaline phosphatase activity in anticonvulsant treatment patients are similar to those in patients with osteomalacia. MJIRI, Vol.5, No.3 & 4,135-137,1991