A new medication, dalfampridine (sold under the name Ampyra) has been approved by the FDA for multiple sclerosis. The new medication does not cure MS or even block the MS attacks. But it reportedly helps patients with MS to walk faster (and presumably better).

How does it do this? Dalfampridine is a potassium channel blocker. In the process of nerve conduction, the potassium channel opens at a certain point to shut off the action potential. Blocking the channel a bit allows the potential to last a little longer and this helps the impulse to propagate through areas of damaged myelin.

For many years this drug as been known under another name, 4-aminopyridine (4-AP).  Previously it had been believed that  4-AP was too toxic to use clinically. But Biogen seems to have reduced the toxicity by using a time released formulation.  Thus it was approved by the FDA. The list of possible side effects is long, however, and includes such nasty items as seizures and relapses of MS itself. So this is not something to be taken lightly. But as clinical experience accumulates, Ampyra may take its place as another tool in the MS treatment toolbox.  By the way, if you look this up you may encounter the name fampridine rather than dalfampridine.  They are the same drug. Fampridine=dalfampridine=4-aminopyridine=4-AP.  They are all names for the same chemical.