Results of treatment changes in patients with apparently drug-resistant chronic epilepsy

Objective: It has long been known that the response to treatment in newly diagnosed epilepsy is better than in chronic epilepsy. However, in the past 15 years, 8 major new antiepileptic drugs have been licensed, and the effect of this wider range of treatment options on prognosis has not been fully assessed. The aim of this study was to quantify the effect of adding a previously unused antiepileptic drug to the treatment regimen in adults with uncontrolled chronic epilepsy that had been resistant to previous antiepileptic drug treatment. Methods: A total of 265 drug additions were studied in 155 adult patients with chronic epilepsy (defined as epilepsy active at least 5 years after and initiation of therapy). Results: About 16% of all drug introductions resulted in seizure freedom (defined as seizure freedom at last follow-up for 12 months or longer), and a 50 to 99% seizure reduction occurred in a further 21%. Of the 155 patients, 28% were rendered seizure free by a drug introduction. Clinical factors associated with a better effect were fewer previously used antiepileptic drugs, shorter duration epilepsy, and idiopathic epilepsy. Interpretation: This study provides a quantitative estimate of the value of changing drug therapy in patients in whom seizures were previously uncontrolled by previous therapy. The application of a systematic protocol to the treatment of chronic epilepsy will improve seizure control in a substantial proportion of cases. The rather nihilistic view that intractability is inevitable if seizure control is not obtained within a few years of the onset of therapy is incorrect.