The correlation between
lamotrigine serum concentration, efficacy, and toxicity in children is controversial. The database of the Clinical Pharmacology Laboratory at Assaf Harofeh Medical Center was retrospectively searched to identify
lamotrigine serum concentrations in children aged 2-19 years with
refractory epilepsy who received
lamotrigine as monotherapy or polytherapy from 2007-2010. Data collected included age at
epilepsy onset, additional
antiepileptic drugs,
lamotrigine dose, monthly seizure frequency before and after
lamotrigine treatment, and side effects. Sixty blood samples were collected from 42 children aged 10.1 ± 4.9 years (range, 2-20 years). Seizure types included complex partial (n = 28), simple partial (n = 7), absence (n = 2), and generalized tonic-clonic (n = 23). Decreased seizure frequency was observed in 38 (63.3%) patients. No correlation with
lamotrigine serum concentration was evident, but seizure frequency was significantly influenced by age and
lamotrigine dose. Side effects were reported in 21 (35%) patients. Only
diplopia was significantly correlated with
lamotrigine serum concentration.
Lamotrigine was more effective at lower doses and in older children.
Lamotrigine serum concentration correlated significantly with
diplopia, but not with other side effects or with clinical efficacy. Overall,
lamotrigine is effective and safe in children with
refractory epilepsy.