Effect of clinical features on antiseizure medication doses in patients with newly diagnosed epilepsy.

Objective: We evaluate the effect of distinct clinical features on anti-seizure medication (ASM) doses in seizure-free and not seizure-free patients aged ≥16 years with new-onset epilepsy. Materials and methods: This study included 459 patients with a validated diagnosis of epilepsy. The most prescribed ASMs were oxcarbazepine (OXC; n = 307), followed by valproic acid (VPA; n = 115), carbamazepine (CBZ; n = 81), and lamotrigine (LTG; n = 67). The seizure freedom rate with their first or subsequent ASM was 88.0%. A retrospective analysis of patient records was performed to determine any association between doses of ASMs and patient characteristics. Results: The median OXC dose in seizure-free patients aged >60 years was 600 mg compared to 900 mg in younger patients. When controlling for age but not in an unadjusted model, the median dose of OXC was lower (300 mg, p = 0.018) for seizure-free patients compared to non-seizure-free patients, and the median dose of OXC was also 300 mg lower among older patients aged >60 years (p < 0.001). The median OXC doses for men aged ≤60 years were 300 mg higher than for women aged >60 years (900 mg vs. 600 mg, p = 0.021). The median dose of VPA was 400 mg higher in men than in women (p < 0.001) and 400 mg higher in not seizure-free patients compared to seizure-free patients only when adjusting for sex (p < 0.001). Higher median doses for CBZ were registered with FAS compared with FBTCS (difference in median doses of 200 mg; p = 0.017). Conclusion: Significant OXC dose differences were detected between age groups, whereas VPA dosing was different in men and women. Moreover, CBZ doses were dependent on some seizure types. These data allow for the individualization of the initial target dosing based on key clinical characteristics.

Prescribed antiseizure medication doses and their relation to defined daily doses for achieving seizure freedom in newly diagnosed patients with epilepsy.

OBJECTIVES: To investigate the antiseizure medication (ASM) doses required to achieve seizure freedom and their correlation with the World Health Organization's defined daily doses (DDDs) in patients aged 16 years or older with newly diagnosed epilepsy. METHODS: The study included 459 patients with a validated diagnosis of new-onset epilepsy. Patient records were retrospectively analyzed to determine the ASM doses in patients with or without seizure freedom during follow-up. The DDD of the relevant ASM was then retrieved. RESULTS: The seizure-freedom rate with first and subsequent ASMs was 88% (404/459 patients) during the follow-up. The mean prescribed doses (PDDs) and PDD/DDD ratio of the most commonly used ASMs, ie, oxcarbazepine (OXC), carbamazepine (CBZ), and valproic acid (VPA), differed significantly between seizure-free and non-seizure-free status (992 mg and 0.99 vs 1132 mg and 1.13; 547 mg and 0.55 vs 659 mg and 0.66; and 953 mg and 0.64 vs 1260 mg and 0.84, respectively). The effect of the OXC dose as the first failed ASM on the possibility of achieving seizure freedom was significant (Fisher's exact test, p = 0.002). Thirty-four of 43 patients (79%) in which an OXC dose of ≤900 mg failed became seizure-free, as compared with 24 of 54 patients (44%) with a failed OXC dose >900 mg. SIGNIFICANCE: The present study provides new insights into the doses of the commonly used ASMs such as OXC, CBZ, and VPA that can lead to seizure freedom as monotherapy or as combination therapy. The higher PDD/DDD ratio of OXC (0.99) than that of CBZ or VPA renders a generalized PDD/DDD comparison highly problematic.

Response to subsequent antiseizure medications after first antiseizure medication failure in newly diagnosed epilepsy.

Objective: There is a lack of studies using the International League Against Epilepsy (ILAE) recommendation to define drug-resistant epilepsy (DRE). This study evaluated the seizure freedom rates of substitution or add-on and subsequent antiseizure medication (ASM) therapies using different proposed definitions of DRE or ASM trials in patients with a failed first ASM. We also identified prognostic factors for 1-year seizure freedom. Methods: This study included 459 patients with epilepsy of whom 151 were not seizure-free after the first ASM. Multilevel mixed-effects logistic regression was used to examine the correlation between observations from the same patient. Results: The overall seizure freedom rate with the first and subsequent ASMs was 88.0% (404/459). The rate of DRE when defined as the failure of two ASMs for any reason was 20.0%, and according to the ILAE definition of DRE, it was 16.3%. After failing the first ASM, 63.6% of patients (96/151) became seizure free with subsequent ASMs and tried an average of 1.9 ASMs (range 1-5). Of the patients who achieved 1-year seizure freedom, 10.1% (41/404) were taking polytherapy and there was no difference between substitution and add-on. All the patients with generalized epilepsy were seizure-free. A favorable prognostic factor was age >60 years and an EEG without epileptiform activity. The efficacies of the different ASMs were largely similar, but drugs that enhanced GABA-mediated inhibitory neurotransmission had the lowest seizure freedom rate. Significance: In adults with newly-diagnosed epilepsy, 1-year seizure freedom was achieved for almost 90% of the patients. After failing the first ASM, two-thirds of the patients responded to subsequent ASM regimens. Our results support the feasibility and applicability of the ILAE concept of an adequate ASM trial and the failure of two ASMs as a definition of DRE.

Response to first antiseizure medication in patients diagnosed with epilepsy.

OBJECTIVES: To investigate the interaction among the efficacy, tolerability and overall effectiveness of the first antiseizure medication in patients 16 years or older with newly diagnosed epilepsy. MATERIALS AND METHODS: The study included 584 patients who were referred to the Tampere University Hospital between 1 January 1995 and 31 December 2005 and were diagnosed with epilepsy. All individuals were retrospectively followed up until 31 December 2006, until reaching at least one year of seizure freedom, or until death if before the cut-off date. RESULTS: Overall, after thorough validation of the epilepsy diagnosis 459 patients comprised the study cohort; among these patients, 73% of males and 60% of females became seizure-free for at least one year with the first antiseizure medication. The seizure freedom rate for focal epilepsy was 67%. There was no significant difference in focal epilepsy to achieve seizure freedom between oxcarbazepine, carbamazepine or valproic acid. The seizure freedom rate among patients above 60 years of age was 67%. For patients with structural and unknown aetiology, seizure freedom rates were 61.5% and 75.3%, respectively. Additionally, epileptiform activity on EEG in patients with focal epilepsy decreased odds of seizure freedom in adjusted logistic regression models (OR 0.55, p=0.036). CONCLUSIONS: This study provides a more positive prediction of seizure freedom compared with previous studies with the onset of epilepsy at 16 years or older with an overall estimation that two-thirds of patients with new-onset epilepsy obtain seizure freedom with the first antiseizure medication.