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.