Dalfampridine (extended release 4-aminopyridine) is shown in three recent randomised controlled trials to improve walking speed in people with multiple sclerosis; however, the trial literature makes it clear that dalfampridine is effective in only a subset of patients. For the neurologist working in an everyday physician's office, a key question arises: How to distinguish the few who experience a meaningful clinical benefit, from the many who do not? This question has not yet been adequately addressed in the available literature.
Keywords: 4-Aminopyridine; cost benefit analysis; multiple sclerosis; treatment outcome; walking speed.