Lamotrigine does not impair motor performance and spontaneous behavior in developing rats.

No data exist on possible effects of lamotrigine on development. Therefore we performed an ontogenetic study with repeated administration of lamotrigine (10 and/or 20 mg/kg ip for 6 consecutive days) starting in rats 12 and 25 days old (Postnatal Days (PD) 12 and 25). Body weights of these animals were checked, their motor skills were repeatedly tested, and their behavior in an open field was studied at three intervals after the end of treatment. Body weight of PD12 animals increased more slowly than that of control siblings; this difference disappeared till adulthood. There were only transient changes on the bar holding test in the PD12 group and on the rotorod test in the PD25 group. The open-field test demonstrated greater exploratory activity (rearing) in the PD25 group only at the age of 48 days but not 1 month later. Lamotrigine administered repeatedly at early developmental stages did not change motor abilities and behavior in an open field.