SAN DIEGO – Newer anticonvulsants do not appear to be associated with the reduced bone mineral density seen with traditional anticonvulsants, based on results from a retrospective Veterans Affairs study.
Observational studies have linked traditional anticonvulsants, such as phenytoin, carbamazepine, and valproic acid, to reduced bone mineral density (Neurology 2004;62:2051-7). There are few data on this score regarding the newer anticonvulsants, including gabapentin, levetiracetam, lamotrigine, and topiramate, drugs increasingly prescribed not only for seizure disorders but for mood disorders and neuropathic pain as well.
Dr. Richard Lee and coworkers at Duke University Medical Center, Durham, N.C., performed a retrospective study of 1,799 patients who underwent bone mineral density measurement at the Durham VA Medical Center from 2005 through June 2010. The study population comprised 679 patients on newer anticonvulsants and 382 on traditional antiepileptic drugs.
Bone mineral density in patients on traditional anticonvulsants was progressively lower at the lumbar spine, total hip, and femoral neck with each additional 90-day period on medication during the previous 10 years, based on a multivariate logistic regression analysis.
In contrast, bone density increased at the lumbar spine and total hip with exposure to the newer nonenzyme-inducing anticonvulsants. There was a nonsignificant trend for increasing bone density at the femoral neck with greater exposure to these agents. For every 90 days on one of the newer nonenzyme-inducing anticonvulsants (lamotrigine, gabapentin, levetiracetam, pregabalin), dual-energy x-ray absorptiometry T scores increased significantly by 0.13 at the lumbar spine and by 0.087 at the total hip.
Topiramate, unlike the other newer anticonvulsants, is enzyme inducing, yet it also showed favorable bone-boosting trends that did not reach statistical significance.
The analysis was adjusted for age, race, body mass index, alcohol and tobacco use, prior fractures, and medical comorbidities. Dr. Lee said he had no disclosures.