Abstracts

Rationale: The goal of anitepileptic drug (AED) treatment is sustained seizure freedom on monotherapy with no or acceptable side effects resulting in a good quality of life. This project examined the characteristics of patients who remined seizure free on single AED at unchanged dosing for at least the previous year. Methods: Data were acquired by database and case sheet interrogation of 6821 patients attending the epilepsy services at Western Infirmary in Glasgow, Scotland between 1982 and 2011. Results: Seizure freedom was achieved on 17 different monotherapies in 1425 patients (687 men, 738 women, aged 18-94 years [median 46 years]). Of these, 1131 (79.3%) had partial seizures with or without secondary generalization and the remaining 294 (20.7%) were classified as having idiopathic generalised epilepsies. Treatment with the first drug produced seizure freedom in 866 (60.7%) of these patients. The remainder were controlled on their 2nd (n=309, 21.7%), 3rd (n=217, 15.2%), 4th (n= 31, 2.2%) or even 5th (n=2, 0.2%) AED as monotherapy. The commonest drugs taken were sodium valproate (n=443, 31.1%), carbamazepine (n=382, 26.8%), lamotrigine (n=318, 22.3%) and levetiracetam (n=82, 5.8%). Of the patients receiving sodium valproate, 67% took ≤1000mg/day mg (range 400-3000mg), whereas 66% of carbamazepine-treated patients took ≤600mg/day mg (range 200-2000mg), 75% of lamotrigine-treated patients took ≤200mg/day mg (range 25-700mg), and 74% of levetiracetam-treated patients took ≤1000mg/day (range 500-3000mg). There was no relationship between AED dosing and number of previous drug schedules. Side effects (108 [81%] neurotoxicity, 26 [19%] other) were reported by 134 (9.4%) patients, particularly those taking carbamazepine (60 of 382, 16%; others 73 of 1043, 7%; p<0.001), all of whom continued on treatment. Patients who failed their first monotherapy due to side-effects or lack of efficacy were more likely to fail their second AED for the same reason prior to eventually becoming seizure free on a subsequent treatment option. Conclusions: Although the majority of patients in this analysis became seizure-free on their first AED, a substantial minority controlled on later monotherapy schedules. Doses were often modest, suggesting that good tolerability is necessary to underpin an optimal response. Some patients seemed more likely to have problems tolerating AEDs, whereas for others lack of efficacy was the major reason for treatment failure. These 2 separate populations may be worthy of further investigation.