Sustained-Release Fampridine (4-Aminopyridine) in Multiple Sclerosis: Efficacy and Impact on Motor Function

OBJECTIVE: The aim of this study was to determine the efficacy of sustained-release fampridine (4-aminopyridine) in veterans with multiple sclerosis (MS) with limited ambulatory ability, and its impact on motor function in an outpatient setting. DESIGN: Retrospective. SETTING: Tertiary referral center [Veterans Affairs (VA) Medical Center]. PARTICIPANTS: Veterans; 20 MS patients were prescribed dalfampridine (10 mg twice daily) due to their difficulty with walking based on patient and caregiver report and clinician impression of change in the ability to ambulate based on prior 10-meter (10M) and 2-minute walk tests (2MWTs). INTERVENTION: Not applicable. MAIN OUTCOME MEASURES: The primary outcome measures were mean changes in walking speed (10M walk test), walking distance (2MWT), and Total Functional Independence Measure (TFIM). Improvement of >20 % in walking speed was indicated as a clinically meaningful change. RESULTS: Treatment with dalfampridine resulted in significant improvement in walking speed and endurance (p < 0.05). Walking speed increased by 33 % and walking endurance by 31 %, representing clinically meaningful improvement. This change was not influenced by change in muscle tone. This improvement in mobility was associated with a clinically significant change in motor function. Adverse effects, including insomnia, dizziness, and headache, were experienced by five patients who discontinued the medication after a minimum of 4 weeks. CONCLUSION: Treatment with dalfampridine resulted in clinically relevant improvements in walking speed and endurance in MS patients with limited ambulation and helped improve their motor function. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s40268-013-0020-x) contains supplementary material, which is available to authorized users.