dalfampridine

thumb|right|240px|4-Aminopyridine 4-Aminopyridine (4-AP) is an organic compound with the chemical formula . It is one of the three isomeric aminopyridines. It is used as a research tool in characterizing subtypes of the potassium channel. It has also been used as a drug, to manage some of the symptoms of multiple sclerosis, and is indicated for symptomatic improvement of walking in adults with several variations of the disease. It was undergoing Phase III clinical trials , and the U.S. Food and Drug Administration (FDA) approved the compound on January 22, 2010. 4-AP has been used as treatment for KCNA2-related disorders with gene mutations that show a clear gain-of-function. Benefits include decreased seizures and improved ataxia, alertness, and cognition. Fampridine is also marketed as Ampyra (pronounced "am-PEER-ah", according to the maker's website) in the United States by Acorda Therapeutics and as Fampyra in the European Union, Canada, and Australia. In Canada, the medication has been approved for use by Health Canada since February 10, 2012.

==Applications== In the laboratory, 4-AP is a useful pharmacological tool in studying various potassium conductances in physiology and biophysics. It is a relatively selective blocker of members of Kv1 (Shaker, KCNA) family of voltage-activated K+ channels. However, 4-AP has been shown to potentiate voltage-gated Ca2+ channel currents independent of effects on voltage-activated K+ channels.