Treatment of epilepsy to optimize bone health

Abstract

When treating a person with epilepsy, one must consider many factors in addition to the obvious need to treat the seizures. Both epilepsy itself and treatment with antiepileptic drugs (AEDs) subject one to numerous potential secondary long-term health concerns. Poor bone health is one of these concerns. Studies suggest that persons with epilepsy treated with AEDs have an increased risk of fracture, low bone mineral density (BMD), and abnormalities in bone metabolism. Multiple factors likely contribute to the increased risk. Falls during generalized tonic-clonic seizures, secondary effects of AEDs on balance, inactivity, low BMD, reduced calcium intake, reduced active vitamin D metabolites, and a genetic predisposition to low BMD may all contribute. Studies suggest a differential influence of AEDs. Phenytoin, phenobarbital, and primidone are most consistently associated with a negative impact on bone. Carbamazepine and valproate may also result in bone abnormalities, but data are mixed. Current studies suggest that lamotrigine has limited (if any) effect, but again, data are inconsistent. Other AEDs have received limited study. Screening for poor bone health includes serologic testing of vitamin D metabolites (notably 25-hydroxyvitamin D) as well as BMD testing using dual energy x-ray absorptiometry. Optimizing intake of calcium and vitamin D is important for all persons with epilepsy treated with AEDs. Although many treatments for low BMD are available, these agents have not been studied in persons with epilepsy treated with AEDs. Overall, physicians treating persons with epilepsy must consider the potential effect of having epilepsy and its main treatment, AED therapy, on bone health. For patients in whom bone health is a particular concern (eg, those with diagnosed bone disease or with significant risk factors for bone disease, including glucocorticosteroid use), it is best to avoid AEDs known to negatively affect bone. In addition, practitioners should work with other treating physicians to optimize bone health in these patients.