Abstracts

Rationale: Long-term antiepileptic drug (AED) use causes multiple abnormalities in calcium and bone metabolism that have been most extensively described in children. The objective is to determine if the vitamin D3 (vit D3) dose (800 unit/day) is appropriate prophylactic to children on long- term (AED). Methods: A retrospective study was conducted of 63 patients (35 males and 28 males between 0-16 years old) on anticonvulsant therapy and vit D3 800 unit per day for at least 6 months who presented to neurologists at a tertiary referral center. Bone mineral density (BMD) as well as serum 25 hydroxyl-vitamins D (25-OHD), serum calcium, parathyroid hormone, and alkaline phosphatase were measured. Signs of vitamin D deficiency were recorded more frequently ere. A detailed questionnaire assessing calcium intake as well as previous and current intake of antiepileptic medications was administered to all patients. Results: Over 90% of children had normal 25-OHD levels, and this finding did correlate with BMD. Subjects on enzyme-inducing drugs such as phenytoin, phenobarbital, carbamazepine, and primidone tended to have lower BMD than those on noninducers such as valproic acid, lamotrigine, clonazepam, gabapentin, topamirate, and ethosuximide. Conclusions: Epilepsy and its therapy, including the newer drugs, are risk factors for low bone density, irrespective of vitamin D levels. It is suggested that a dose 800 unit/day of vitamin D might be most suitable to avoid biochemical signs of vitamin D deficiency in children on antiepileptic drugs but monitoring of 25-OHD levels level is still indicated to adjust the dose in patients on chronic antiepileptic therapy.