Three double-blind, randomized, placebo-controlled studies of topiramate that include children have been published and prospective but unblinded and retrospective reviews have been reported providing information regarding topiramate's safety and tolerability. These studies indicate that side effects tend to occur early in treatment with topiramate, especially in children receiving polypharmacy. Two classes of adverse events are commonly reported: central nervous system and anorexia/weight loss. Central nervous system effects include somnolence, difficulties with concentration, and behavior changes. Tolerance to these effects seems to develop in most children. When it occurs, weight loss has been noted in the first 12 to 18 months, after which normal weight gain resumes, without long-term impact on growth. As opposed to the experience in adults, aphasia and word-finding difficulties are not commonly seen, and parasthesiae are not reported by children. Renal calculi are rare. Life-threatening idiosyncratic reactions have not been attributed to topiramate. While metabolic acidosis has been reported, no other clinically significant laboratory abnormalities have been associated with the use of topiramate in children.