The effectiveness and safety of topiramate in 87 children with intractable epilepsy treated at three Canadian Centers were evaluated at the IWK-Grace Health Centre, Halifax, NS, Canada. Seizure reduction was >90% in 8 (9%), 50-90% in 21 (24%), and <50% in 54 (62%) of patients. Treatment was discontinued in 36 (41%) because of adverse events, especially cognitive dulling, in 27 (31%). The occurrence of cognitive dulling was not related to the rate of dose escalation and final dose level. 
COMMENT. Cognitive dysfunction can be a serious and frequent side effect of topiramate treatment of intractable epilepsy in children.