Bone health and antiseizure drugs: Diagnosis and management

There is growing evidence for the association of antiepileptic medications (AEDs) and bone disease. Increased rates of vitamin D deficiency, elevated laboratory markers of bone turnover and increased rates of osteopenia, osteomalacia and fracture have all been reported: Although most commonly attributed to anticonvulsants that induce hepatic cytochrome P450 (CYP) enzymes, recent studies suggest that valproate, a CYP inhibitor, is also problematic. Data specific to other newer AEDs are lacking. Drug-induced inactivation of vitamin D is the most widely proposed mechanism for AED-related bone disease, however, other not yet fully elucidated pathways must also contribute. There are currently no evidence-based guidelines for diagnosis or treatment of bone disease specific to persons on AED therapy. Periodic screening for vitamin D deficiency and with dual-energy x-ray absorptiometry is likely beneficial. Prophylactic supplementation with vitamin D and calcium can be considered for all patients on AEDs, unless it is clear that dietary intake is sufficient. Higher dose vitamin D therapy may be required in the presence of osteomalacia. For diagnosed osteoporosis, standard pharmacologic therapies including bisphosphonates can be utilized, but have yet to be formally studied in this population.