Effects of vigabatrin on the skeletal system of young rats.

Long-term administration of antiepileptic drugs may be connected with the risk of impairment of bone remodeling. Contrary to the reported unfavorable effect of classic antiepileptic drugs on bone metabolism, little is known about the effect of the next generation antiepileptics on bone remodeling. The aim of the present study was to investigate the effect of vigabatrin, as a representative of new antiepileptics, on the skeletal system of young rats, in comparison with conventional drugs--phenytoin and valproic acid. The experiments were carried out on 4-week-old male Wistar rats, divided into the control rats, and rats receiving vigabatrin (250 mg/kg p.o. daily), phenytoin (20 mg/kg p.o. daily) or valproic acid (250 mg/kg p.o. daily). The drugs were administered for 28 days. Histomorphometric parameters of the tibia and femur, mechanical properties of the femur, and bone length, diameter, mass, content of mineral substances and calcium were examined. After administration of phenytoin or valproic acid, the investigated bone parameters did not significantly differ from those observed in the control rats. Administration of vigabatrin caused profound impairment of bone accrual with impairment of bone histomorphometric parameters, along with the significant decrease in the body mass gain.