Drug treatment-related factors of inadequate seizure control

To optimize seizure control it is important to identify modifiable factors. We conducted a case–control study to explore to what extent drug treatment-related factors are associated with seizures. Eighty-six patients with epilepsy were evaluated: 45 cases (recently experienced a seizure) and 41 controls (seizure-free for at least 2 months). There was a significant association between low AED serum concentration and seizures (odds ratio (OR) = 8.9, 95% confidence interval (CI) = 1.7–47.8), compliance was not associated with seizures (OR = 0.9, 95% CI = 0.2–4.0), and changes in medication (mainly non-AEDs) were more frequently observed in the case group than in the control group (OR = 4.1, 95% CI = 0.9–18.3). These findings indicate that patients with low AED serum levels have a nine times higher risk of seizures compared with patients with therapeutic AED levels and that changes in medication regimens in patients with epilepsy should be made with care.