Effects of zonisamide monotherapy on bone health in drug‐naive epileptic patients

• Published in: Epilepsia (Copenhagen) 2020-10, Vol.61 (10), p.2142-2149
• Main Authors: Koo, Dae Lim, Nam, Hyunwoo
• Format: Article
• Language: English
• Subjects: Absorptiometry, Photon - methods; Adolescent; Adult; Age; Aged; Alkaline phosphatase; Analysis of covariance; Anticonvulsants - pharmacology; Anticonvulsants - therapeutic use; Antiepileptic agents; Biochemical markers; Biomarkers; Biomarkers - blood; Body mass index; Bone Density - drug effects; Bone Density - physiology; bone metabolism; Bone mineral density; Bone strength; Bone turnover; Epilepsy; Epilepsy - blood; Epilepsy - diagnostic imaging; Epilepsy - drug therapy; Female; Femur; Follow-Up Studies; Humans; Male; Metabolism; Middle Aged; Osteocalcin; Parathyroid; Parathyroid hormone; Republic of Korea - epidemiology; Sex; Spine (lumbar); Treatment Outcome; Vitamin D3; Young Adult; Zonisamide; Zonisamide - pharmacology; Zonisamide - therapeutic use
• ISSN: 0013-9580; 1528-1167
• DOI: 10.1111/epi.16678

Objective Alteration of bone strength is an adverse effect of antiepileptic drug treatment. We investigated the effects of zonisamide (ZNS) monotherapy on bone mineral density (BMD) and biomarkers of bone metabolism after 13 months of treatment in drug‐naive epileptic patients. Methods Fifty‐nine patients with new onset drug‐naive epilepsy were enrolled (29 women, 30 men; mean age = 31.5 ± 11.5 years). The BMD and T scores were measured at the lumbar spine and femoral neck by using dual‐energy X‐ray absorptiometry. Biomarkers specific for bone metabolism (bone‐specific alkaline phosphatase, parathyroid hormone, osteocalcin, insulinlike growth factor‐1, C‐telopeptide, and vitamin D3 levels) were measured before and after long‐term ZNS monotherapy. Analysis of covariance (ANCOVA) was used to estimate BMD and biomarkers of bone metabolism before and after ZNS therapy. Age, sex, treatment duration, and ZNS dosage were included as covariates for adjustment in the ANCOVA model. Furthermore, subgroup analyses were performed for each sex, and the effect size was calculated. Results After 13 months of ZNS treatment, the BMD and T scores at the lumbar spine (L1‐L4 level) and femoral neck were not significantly different. Moreover, the biochemical markers showed no significant differences after ZNS monotherapy. Women showed significantly decreased baseline BMD at the femoral neck compared to men (P = .026), although the mean age and body mass index were not significantly different between the sexes. No significant changes in BMD or biomarkers of bone metabolism were seen in either sex after 13 months of ZNS treatment. Significance The results suggest that long‐term ZNS monotherapy does not affect bone health in drug‐naive patients with epilepsy negatively.