Withdrawal of antiepileptic drug treatment in childhood epilepsy: factors related to age.

The clinical and electroencephalographic changes with age were evaluated in 304 patients with childhood epilepsies, whose antiepileptic treatment had been discontinued after a seizure free period of more than three years. The withdrawal rate differed significantly between epileptic syndromes, being higher in idiopathic epilepsy and lower in symptomatic epilepsy. The age at withdrawal was characteristic for each epileptic syndrome, and generally showed two peaks: at preadolescence and early school age. Forty one (13.5%) of the 304 patients experienced relapses. The relapse rate differed between epileptic syndromes. Relapses occurred at a unique age in each epileptic syndrome, and were frequent in preadolescence and early adulthood. Electroencephalography that still showed paroxysmal discharges at withdrawal did not necessarily predict the occurrence of a relapse, but the changes in background activity with age, which may indicate maturation of the CNS, were significantly different between the patients with and those without relapses. The results suggest that age related to each epileptic syndrome should be considered when deciding on withdrawal of antiepileptic drugs.