K K Jain MD (Dr. Jain is a consultant in neurology and has no relevant financial relationships to disclose.)
Originally released January 25, 2010; last updated January 23, 2020; expires January 24, 2023

This article includes discussion of dalfampridine, 4-aminopyridine, extended-release fampridine, and prolonged-release fampridine. The foregoing terms may include synonyms, similar disorders, variations in usage, and abbreviations.

Historical note and terminology

Dalfampridine is an extended-release formulation of fampridine (4-aminopyridine). 4-aminopyridine has a restricted use as an extremely effective bird poison sold under the brand name Avitrol, which is highly toxic to all mammals, including humans, if dosages are exceeded. Compounded forms of the active agent of sustained-release fampridine have been used in clinical practice for many years and shown to improve walking ability in patients with multiple sclerosis. Clinical trials have now been completed that demonstrate effectiveness of the drug with statistical significance and clinically meaningful end points (Kachuck 2009). In 2010, the FDA approved dalfampridine (Ampyra™), which is the first oral therapy for multiple sclerosis. Approval of dalfampridine will enable patients to obtain a consistent exact dosage in a guaranteed time-released formula and avoids the risk of getting an uncertain preparation from a compounding pharmacy with possible adverse effects. A life-threatening accidental overdose of fampridine due to a compounding pharmacy error has been reported (Schwam 2009).

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