Ampyra (dalfampyridine)

Dalfampridine (also called 4-aminopyridine and Ampyra) is a chemical that has been around a long time.  It has been available to treat MS since 2010.  It is manufactured by Biogen.  The mechanism of action is blockade of potassium channels in nerve tissue, leading to better conduction of signals.  This may be particularly helpful to injured nerve tissue.

Dalfampridine is often called the “walking drug” because it was shown to improve walking ability in patients with progressive MS symptoms.  Although not all patients respond to this treatment, patients who respond report a “25% improvement” in their walking, on average.

Dalfampridine is provided as a 10 mg tablet taken twice per day.

The annual retail cost of brand name Dalfampridine is $20000/yr in the U.S.

Many patients who cannot afford Dalfampridine / Ampyra consider 4-aminopyridine as a replacement.  Although this is not available from a traditional pharmacy, a compounding pharmacy may provide it with a physician’s prescription.

Possible side effects of Dalfampridine include dizziness, trouble with balance. nausea, headache, back pain, weakness, trouble sleeping and urinary tract infection.  At higher doses, patients have reported having a seizure as a side effect.

Literature search

van Diemen HA et al.  1992.  The effect of 4-aminopyridine on clinical signs in multiple sclerosis; a randomized, placebo-controlled, double blind, cross-over study.  Ann Neurol 32(2): 123-30
Results: 4-aminopyridine appeared to reduce disability rating in patients with MS over 12 weeks compared to placebo

Goodman, A.D., et al. 2010.  A phase 3 trial of extended release oral dalfampridine in multiple sclerosis.  Ann Neurol. Oct; 68(4) 494-502
Results: over 8 weeks, extended release dalfampridine resulted in improvement in walking times in 120 patients with MS compared to placebo