Exploring efficacy and tolerability outcomes in patients with difficult-to-treat epilepsy receiving adjunctive topiramate at different titration rates--an exploratory study

Severity of Topiramate-Related Working Memory Impairment Is Modulated by Plasma Concentration and Working Memory Capacity

Drug side effects that impair cognition can lead to diminished quality of life and discontinuation of therapy. Topiramate is an antiepileptic drug that elicits cognitive deficits more frequently than other antiepileptic drugs, impairing multiple cognitive domains including language, attention, and memory. Although up to 40% of individuals taking topiramate may experience cognitive deficits, we are currently unable to predict which individuals will be most severely affected before administration. The objective of this study was to show the contributions of plasma concentration and working memory capacity in determining the severity of an individual's topiramate-related cognitive impairment. Subjects were enrolled in a double-blind, placebo-controlled crossover study during which they received a single dose of either 100, 150, or 200 mg topiramate. Working memory function was assessed using a modified Sternberg working memory task with 3 memory loads administered 4 hours after dosing. After adjustment for differences in working memory capacity, each 1 μg/mL of topiramate plasma concentration was associated with a 3.6% decrease in accuracy for all memory loads. Placebo effects occurred as a function of working memory capacity, with individuals with high working memory capacity experiencing less severe placebo-related impairment compared with those with low working memory capacity. Our results demonstrate that severity of topiramate-related cognitive deficits occurs as a function of both drug exposure and baseline cognitive function. By identifying patient- and exposure-related characteristics that modulate the severity of cognitive side effects, topiramate dosing strategies may be individually tailored in the future to prevent unwanted cognitive impairment.

Prevention of episodic migraines with topiramate: results from a non-interventional study in a general practice setting

The majority of patients with migraine headaches are treated in non-specialized institutions though data on treatment outcomes are largely derived from tertiary care centers. The current non-interventional study explores efficacy and tolerability outcomes of patients with episodic migraines receiving topiramate as preventive agent in a general practice setting. A total of 366 patients (87% female, mean age 41.8 +/- 11.6 years) were eligible for migraine prevention and treated with flexible dose topiramate for 6 months (core phase), and optionally for a total of 12 months (follow-up phase). Overall, 261 patients (77.7% of safety analysis set, SAF) completed the core phase. Reasons for discontinuation included adverse events (2.1%), lost to follow-up (1.8%), other reasons (1.5%), and end of therapy (0.3%) though in the majority of patients who discontinued no reasons were listed. The median daily dose at endpoint was 50 mg/day (range, 25-187.5 mg/day). The median days with migraine headaches decreased from 6.0 to 1.2 days (p < 0.001), median pain intensity score decreased from 17.0 to 3.2 points (p < 0.001). In women with reported menstruation-associated migraine, the median number of migraine attacks decreased from 4.0 to 0.9 (p < 0.001). Absenteeism as well as triptan use decreased significantly, and significant improvements in activities of daily living and quality of life were reported. The most frequently reported AEs were paraesthesia (4.2%) and nausea (3%). Results suggest that migraine prevention with topiramate in a general practice is generally well tolerated and associated with a significant improvement in migraine headaches and related functional impairment.