Effectiveness of first antiepileptic drug

Purpose: To investigate the interaction among efficacy, tolerability, and o verall effectiveness of the first antiepileptic drug (AED) in patients with newly diagnosed epilepsy. Methods: The 470 patients were diagnosed, treated and followed up from Janu ary 1984 at a single center. Outcome was classified as seizure freedom for at least the last year or failure of initial treatment because of inadequat e seizure control, adverse events, or for other reasons. Results: Overall, 47% of patients became seizure-free with the first prescr ibed AED. A higher proportion (p = 0.025) of patients with symptomatic or c ryptogenic epilepsy changed treatment because of intolerable side effects ( 17%), and a lower proportion (p = 0.007) became seizure-free (43.5%) compar ed with those with idiopathic epilepsy (8.5% and 58%, respectively). Most p atients (83%) received carbamazepine (CBZ; n = 212), sodium valproate (VPA, n = 101), or lamotrigine (LTG; n = 78). The majority of seizure-free patie nts required only a moderate daily AED dose (93.1% with less than or equal to 800 mg CBZ, 91.3% with less than or equal to1,500 mg VPA, 93.8% with les s than or equal to 300 mg LTG), with commonest dose ranges being 400-600 mg for CBZ, 600-1,000 mg for VPA, and 125-200 mg for LTG. Most withdrawals du e to poor tolerability also occurred at or below these dose levels (CBZ: 98 %; VPA: 100% LTG: 75%). Patients taking CBZ (27%) had a higher incidence of adverse events necessitating a change of treatment than did those treated with VPA (13%) or LTG (10%), resulting in fewer becoming seizure-free (CBZ vs. VPA, p = 0.02; CBZ vs. LTG, p = 0.002). Conclusions: Nearly 50% of newly diagnosed patients became seizure-free on the first-ever AED, with > 90% doing so at moderate or even modest dosing. Tolerability was as important as efficacy in determining overall effectiven ess.