[9] It was undergoing Phase III clinical trials as of 2008[update],[10] and the U.S. Food and Drug Administration (FDA) approved the compound on January 22, 2010.

[11] Fampridine is also marketed as Ampyra (pronounced "am-PEER-ah," according to the maker's website) in the United States by Acorda Therapeutics[11][12] and as Fampyra in the European Union, Canada, and Australia.

[19] The amount of bait should be limited so that relatively few birds are poisoned, causing the remainder of the flock to be frightened away with a minimum of mortality.

It acts by blocking voltage-gated potassium channels, prolonging action potentials and thereby increasing neurotransmitter release at the neuromuscular junction.

[22] Fampridine has been shown to improve visual function and motor skills and relieve fatigue in patients with multiple sclerosis (MS).

Strong potassium currents decrease action potential duration and amplitude, which increases the probability of conduction failure − a well documented characteristic of demyelinated axons.

Potassium channel blockade has the effect of increasing axonal action potential propagation and improving the probability of synaptic vesicle release.

Although improving symptoms, 4-AP does not inhibit progression of MS. Another study, conducted in Brazil, showed that treatment based on fampridine was considered efficient in 70% of the patients.

The drug was originally intended, by Acorda Therapeutics, to have the brand name Amaya, however the name was changed to Ampyra to avoid potential confusion with other marketed pharmaceuticals.