Abstract. Background: Fampyra is a potassium channel blocker that reduces the leakage through ion-channels. Fampyra is approved for use in patients with multiple sclerosis (MS) who have walking difficulties. Previous studies have shown that Fampyra can have a positive effect on walking speed in patients with MS. Objectives: To investigate the effect of Fampyra in a group of MS patients and see the effect on walking speed and endurance. In addition, we wanted to examine whether factors such as age, gender, degree of handicap and physical activity could predict response to treatment. Methods: The patients treated with Fampyra were tested before starting treatment and after two weeks and three months. 25-foot walk test and 2-min walk test were preformed. In addition, patients were asked to complete a questionnaire on physical activity. Results: 135 patients, 78 women and 57 men initiated treatment with Fampyra. The patients in our study had a mean age of 54,5 years, mean EDSS 5,6 and mean disease duration of 13,4 years. 65,8% completed three months of Fampyra, 34,1% did stop medication due to perceived lack of efficacy or side effects. Conclusions: Fampyra was associated with improvements in walking speed and walking distance. The study could not identify any significant differences considering age, gender or degree of handicap predicting treatment response
