ABSTRACT

This study sought to determine the risk for osteopenia and osteoporosis and to evaluate hormonal and biochemical parameters suggesting bone mineral metabolism disturbances in patients on long-term monotherapy with carbamazepin (CBZ) or valproic acid (VPA).

The study included 36 epileptic ambulatory children (20 boys, 16 girls; mean age 9.3±3.3 years; range 4 to 15 years) treated either with VPA (n=23) or CBZ (n=13) as monotherapy for 2 to 3 years. Serum calcium, phosphorus, and alkaline phosphotase levels were determined and bone mineral density was measured by DEXA scanning at the L2-L4 levels of lumbar spine in patients and age-matched controls. In addition, serum levels of 25-hydroxy-vitamin D (25-OH Vitamin D), calcitonin, parathormone, osteocalcin, IGF-1 (insulin-like growth factor-1) and IGFBP-3 (insulin-like growth factor binding protein-3) were measured in 26 patients with epilepsy and the results were compared with age- and sex-matched normal values.

Osteoporosis was detected in only one patient (4%) on VPA treatment, whereas osteopenia was detected in 30% of the VPA group, 47% of the CBZ group, and 20% of the control group. Bone mineral density values did not differ significantly between the VPA and CBZ groups and the controls (p>0.05). Serum levels of 25-OH Vitamin D, calcitonin, parathormone, IGF-1, and IGFBP-3 were found within normal ranges in epileptic patients.

Our results indicate that long-term CBZ and VPA therapy can result in changes in bone mineral density before the hormonal and biochemical parameters related to bone metabolism have been affected.

Keywords: Anticonvulsants/adverse effects, bone density/drug effects, carbamazepine/adverse effects, epilepsy/drug therapy, valproic acid/adverse effects