The combination of lamotrigine and valproate/divalproex sodium has been shown to be effective in the treatment of refractory epilepsy. This study aims to evaluate the pharmacologic properties of using this combination in a pediatric population refractory to antiepileptic drugs, with an extended follow-up. We studied a group of 51 patients, ranging from 4 to 16 years of age. Sixteen patients (31.4%) had generalized epilepsy and 35 (69.6%) had focal epilepsy. The combination was effective in 39 patients (76.5%) in the first year of follow-up and in 36 patients (70.6%) in the second year, with a reduction in drop attacks observed in 22 (88.5%). Adverse effects included rash, leading to discontinuation in four patients (7.8%). Slower introduction of lamotrigine minimizes adverse effects, thereby improving quality of life and adherence to treatment. In addition, therapeutic efficacy is maintained with lower doses of lamotrigine, even after the first year of treatment.